Sustainable architectureFrom Wikipedia, the free encyclopedia

Energy-plus-housesatFreiburg-Vaubanin GermanySustainable architectureisarchitecturethat seeks to minimize the negative environmental impact of buildings by efficiency and moderation in the use of materials, energy, and development space. Sustainable architecture uses a conscious approach to energy and ecological conservation in the design of the built environment.[1]The idea of sustainability, orecological design, is to ensure that our actions and decisions today do not inhibit the opportunities of future generations.[2]Contents[hide] 1Sustainable energy use 1.1Heating, ventilation and cooling system efficiency 1.2Renewable energy generation 1.2.1Solar panels 1.2.2Wind turbines 1.2.3Solar water heating 1.2.4Heat pumps 2Sustainable building materials 2.1Recycled materials 2.2Lower volatile organic compounds 2.3Materials sustainability standards 3Waste management 4Building placement 5Sustainable building consulting 6Changing pedagogies 7Sustainable urbanism and architecture 8Criticism 9See also 10References 11External linksSustainable energy use[edit]Main articles:Low-energy houseandZero-energy building

K2 sustainable apartments inWindsor, Victoria, Australia by DesignInc (2006) featurespassive solar design, recycled and sustainable materials,photovoltaic cells,wastewater treatment,rainwater collectionandsolar hot water.

Thepassivhausstandard combines a variety of techniques and technologies to achieve ultra-low energy use.

Following its destruction by a tornado in 2007, the town ofGreensburg, Kansas(USA) elected to rebuild to highly stringent LEED Platinum environmental standards. Shown is the town's new art center, which integrates its own solar panels and wind generators for energy self-sufficiency.Energy efficiencyover the entire life cycle of a building is the single most important goal of sustainable architecture.Architectsuse many different techniques to reduce the energy needs of buildings and increase their ability to capture or generate their own energy.Heating, ventilation and cooling system efficiency[edit]The most important andcost-effectiveelement of an efficientheating, ventilating, and air conditioning (HVAC)system is awell-insulated building. A more efficient building requires less heat generating or dissipating power, but may require more ventilation capacity to expelpolluted indoor air.Significant amounts of energy are flushed out of buildings in the water, air andcompoststreams.Off the shelf, on-site energy recycling technologies can effectively recaptureenergy from wastehot water and stale air and transfer that energy into incoming fresh cold water or fresh air. Recapture of energy for uses other than gardening from compost leaving buildings requires centralizedanaerobic digesters.HVAC systems are powered by motors.Copper, versus other metal conductors, helps to improve the electrical energy efficiencies of motors, thereby enhancing the sustainability of electrical building components.(For main article, see:Copper in energy-efficient motors).Site and building orientation have some major effects on a building's HVAC efficiency.Passive solar building designallows buildings to harness the energy of the sun efficiently without the use of anyactive solarmechanisms such asphotovoltaic cellsorsolar hot water panels. Typicallypassive solarbuilding designs incorporate materials with highthermal massthat retain heat effectively and stronginsulationthat works to prevent heat escape. Low energy designs also requires the use of solar shading, by means of awnings, blinds or shutters, to relieve the solar heat gain in summer and to reduce the need for artificial cooling. In addition,low energy buildingstypically have a very low surface area to volume ratio to minimize heat loss. This means that sprawling multi-winged building designs (often thought to look more "organic") are often avoided in favor of more centralized structures. Traditional cold climate buildings such asAmericancolonialsaltboxdesigns provide a good historical model for centralized heat efficiency in a small-scale building.Windows are placed to maximize the input of heat-creating light while minimizing the loss of heat through glass, a poor insulator. In thenorthern hemispherethis usually involves installing a large number of south-facing windows to collect direct sun and severely restricting the number of north-facing windows. Certain window types, such as double or triple glazedinsulated windowswith gas filled spaces andlow emissivity (low-E)coatings, provide much better insulation than single-pane glass windows. Preventing excess solar gain by means of solar shading devices in the summer months is important to reduce cooling needs.Deciduous treesare often planted in front of windows to block excessive sun in summer with their leaves but allow light through in winter when their leaves fall off. Louvers or light shelves are installed to allow the sunlight in during the winter (when the sun is lower in the sky) and keep it out in the summer (when the sun is high in the sky).Coniferousorevergreen plantsare often planted to the north of buildings to shield against cold north winds.In colder climates, heating systems are a primary focus for sustainable architecture because they are typically one of the largest single energy drains in buildings.In warmer climates where cooling is a primary concern, passive solar designs can also be very effective. Masonrybuilding materialswithhigh thermal massare very valuable for retaining the cool temperatures of night throughout the day. In addition builders often opt for sprawling single story structures in order to maximize surface area and heat loss.[citation needed]Buildings are often designed to capture and channel existing winds, particularly the especially cool winds coming from nearbybodies of water. Many of these valuable strategies are employed in some way by thetraditional architectureof warm regions, such as south-western mission buildings.In climates with four seasons, an integrated energy system will increase in efficiency: when the building is well insulated, when it is sited to work with theforces of nature, when heat is recaptured (to be used immediately or stored), when the heat plant relying onfossil fuelsor electricity is greater than 100% efficient, and whenrenewable energyis used.Renewable energy generation[edit]

BedZED(Beddington Zero Energy Development), the UK's largest and first carbon-neutral eco-community: the distinctive roofscape with solar panels and passive ventilation chimneysSolar panels[edit]Main article:Solar PVActive solardevices such asphotovoltaicsolar panelshelp to provide sustainable electricity for any use. Electrical output of a solar panel is dependent on orientation, efficiency, latitude, and climatesolar gain varies even at the same latitude. Typical efficiencies for commercially available PV panels range from 4% to 28%. The low efficiency of certain photovoltaic panels can significantly affect the payback period of their installation.[3]This low efficiency does not mean that solar panels are not a viable energy alternative. In Germany for example, Solar Panels are commonly installed in residential home construction.Roofs are often angled toward the sun to allow photovoltaic panels to collect at maximum efficiency. In the northern hemisphere, a true-south facing orientation maximizes yield for solar panels. If true-south is not possible, solar panels can produce adequate energy if aligned within 30 of south. However, at higher latitudes, winter energy yield will be significantly reduced for non-south orientation.To maximize efficiency in winter, the collector can be angled above horizontal Latitude +15. To maximize efficiency in summer, the angle should be Latitude -15. However, for an annual maximum production, the angle of the panel above horizontal should be equal to its latitude.[4]Wind turbines[edit]Main article:Wind powerThe use of undersized wind turbines in energy production in sustainable structures requires the consideration of many factors. In considering costs, small wind systems are generally more expensive than larger wind turbines relative to the amount of energy they produce. For small wind turbines, maintenance costs can be a deciding factor at sites with marginal wind-harnessing capabilities. At low-wind sites, maintenance can consume much of a small wind turbine's revenue.[5]Wind turbines begin operating when winds reach 8mph, achieve energy production capacity at speeds of 32-37mph, and shut off to avoid damage at speeds exceeding 55mph.[5]The energy potential of a wind turbine is proportional to the square of the length of its blades and to the cube of the speed at which its blades spin. Though wind turbines are available that can supplement power for a single building, because of these factors, the efficiency of the wind turbine depends much upon the wind conditions at the building site. For these reasons, for wind turbines to be at all efficient, they must be installed at locations that are known to receive a constant amount of wind (with average wind speeds of more than 15mph), rather than locations that receive wind sporadically.[6]A small wind turbine can be installed on a roof. Installation issues then include the strength of the roof, vibration, and the turbulence caused by the roof ledge. Small-scale rooftop wind turbines have been known to be able to generate power from 10% to up to 25% of the electricity required of a regular domestic household dwelling.[7]Turbines for residential scale use are usually between 7 feet (2 m) to 25 feet (8 m) in diameter and produce electricity at a rate of 900 watts to 10,000 watts at their tested wind speed.[8]Building integrated wind turbine performance can be enhanced with the addition of an aerofoil wing on top of a roof mounted turbine.[9]See also:Design feasibilIty of Wind turbine systemsSolar water heating[edit]Main article:Solar thermal powerSolar water heaters, also called solar domestic hot water systems, can be a cost-effective way to generate hot water for a home. They can be used in any climate, and the fuel they usesunshineis free.[10]There are two types of solar water systems- active and passive. An active solar collector system can produce about 80 to 100 gallons of hot water per day. A passive system will have a lower capacity.[11]There are also two types of circulation, direct circulation systems and indirect circulation systems. Direct circulation systems loop the domestic water through the panels. They should not be used in climates with temperatures below freezing. Indirect circulation loops glycol or some other fluid through the solar panels and uses a heat exchanger to heat up the domestic water.The two most common types of collector panels are Flat-Plate and Evacuated-tube. The two work similarly except that evacuated tubes do not convectively lose heat, which greatly improves their efficiency (5%-25% more efficient). With these higher efficiencies, Evacuated-tube solar collectors can also produce higher-temperature space heating, and even higher temperatures for absorption cooling systems.[12]Electric-resistance water heaters that are common in homes today have an electrical demand around 4500kWh/year. With the use of solar collectors, the energy use is cut in half. The up-front cost of installing solar collectors is high, but with the annual energy savings, payback periods are relatively short.[12]Heat pumps[edit]Air-source heat pumps (ASHP) can be thought of as reversible air conditioners. Like an air conditioner, an ASHP can take heat from a relatively cool space (e.g. a house at 70F) and dump it into a hot place (e.g. outside at 85F). However, unlike an air conditioner, the condenser and evaporator of an ASHP can switch roles and absorb heat from the cool outside air and dump it into a warm house.Air-source heat pumps are inexpensive relative to other heat pump systems. However, the efficiency of air-source heat pumps decline when the outdoor temperature is very cold or very hot; therefore, they are only really applicable in temperate climates.[12]For areas not located in temperate climates, ground-source (or geothermal) heat pumps provide an efficient alternative. The difference between the two heat pumps is that the ground-source has one of its heat exchangers placed undergroundusually in a horizontal or vertical arrangement. Ground-source takes advantage of the relatively constant, mild temperatures underground, which means their efficiencies can be much greater than that of an air-source heat pump. The in-ground heat exchanger generally needs a considerable amount of area. Designers have placed them in an open area next to the building or underneath a parking lot.Energy Star ground-source heat pumps can be 40% to 60% more efficient than their air-source counterparts. They are also quieter and can also be applied to other functions like domestic hot water heating.[12]In terms of initial cost, the ground-source heat pump system costs about twice as much as a standard air-source heat pump to be installed. However, the up-front costs can be more than offset by the decrease in energy costs. The reduction in energy costs is especially apparent in areas with typically hot summers and cold winters.[12]Other types of heat pumps are water-source and air-earth. If the building is located near a body of water, the pond or lake could be used as a heat source or sink. Air-earth heat pumps circulate the building's air through underground ducts. With higher fan power requirements and inefficient heat transfer, Air-earth heat pumps are generally not practical for major construction.Sustainable building materials[edit]See also:Green buildingSome examples of sustainable building materials include recycleddenimor blown-in fiber glass insulation, sustainably harvested wood,Trass,Linoleum,[13]sheep wool,concrete(high and ultra high performance[14]roman self-healing concrete[15]), panels made from paper flakes, baked earth, rammed earth, clay, vermiculite, flax linnen, sisal, seegrass, expanded clay grains, coconut, wood fibre plates, calcium sand stone, locally obtained stone and rock, andbamboo, which is one of the strongest and fastest growingwoody plants, and non-toxic low-VOCglues and paints.Recycled materials[edit]

Recycling items for buildingSustainable architecture often incorporates the use of recycled or second hand materials, such asreclaimed lumberandrecycled copper. The reduction in use of new materials creates a corresponding reduction inembodied energy(energy used in the production of materials). Often sustainable architects attempt to retrofit old structures to serve new needs in order to avoid unnecessary development. Architectural salvage and reclaimed materials are used when appropriate. When older buildings are demolished, frequently any good wood is reclaimed, renewed, and sold as flooring. Any gooddimension stoneis similarly reclaimed. Many other parts are reused as well, such as doors, windows, mantels, and hardware, thus reducing the consumption of new goods. When new materials are employed, green designers look for materials that are rapidly replenished, such asbamboo, which can be harvested for commercial use after only 6 years of growth,sorghumor wheat straw, both of which are waste material that can be pressed into panels, orcork oak, in which only the outer bark is removed for use, thus preserving the tree. When possible, building materials may be gleaned from the site itself; for example, if a new structure is being constructed in a wooded area, wood from the trees which were cut to make room for the building would be re-used as part of the building itself.Lower volatile organic compounds[edit]Low-impact building materials are used wherever feasible: for example, insulation may be made from low VOC (volatile organic compound)-emitting materials such asrecycled denimorcellulose insulation, rather than thebuilding insulation materialsthat may contain carcinogenic or toxic materials such as formaldehyde. To discourage insect damage, these alternate insulation materials may be treated withboric acid. Organic or milk-based paints may be used.[16]However, a common fallacy is that "green" materials are always better for the health of occupants or the environment. Many harmful substances (including formaldehyde, arsenic, and asbestos) are naturally occurring and are not without their histories of use with the best of intentions. A study of emissions from materials by the State of California has shown that there are some green materials that have substantial emissions whereas some more "traditional" materials actually were lower emitters. Thus, the subject of emissions must be carefully investigated before concluding that natural materials are always the healthiest alternatives for occupants and for the Earth.[17]Volatile organic compounds (VOC) can be found in any indoor environment coming from a variety of different sources. VOCs have a high vapor pressure and low water solubility, and are suspected of causingsick building syndrometype symptoms. This is because many VOCs have been known to cause sensory irritation and central nervous system symptoms characteristic to sick building syndrome, indoor concentrations of VOCs are higher than in the outdoor atmosphere, and when there are many VOCs present, they can cause additive and multiplicative effects.Green products are usually considered to contain fewer VOCs and be better for human and environmental health. A case study conducted by the Department of Civil, Architectural, and Environmental Engineering at the University of Miami that compared three green products and their non-green counterparts found that even though both the green products and the non-green counterparts both emitted levels of VOCs, the amount and intensity of the VOCs emitted from the green products were much safer and comfortable for human exposure.[18]Materials sustainability standards[edit]Despite the importance of materials to overall building sustainability, quantifying and evaluating the sustainability of building materials has proven difficult. There is little coherence in the measurement and assessment of materials sustainability attributes, resulting in a landscape today that is littered with hundreds of competing, inconsistent and often imprecise eco-labels,standardsandcertifications. This discord has led both to confusion among consumers and commercial purchasers and to the incorporation of inconsistent sustainability criteria in larger building certification programs such asLEED. Various proposals have been made regarding rationalization of the standardization landscape for sustainable building materials.[19]Waste management[edit]Waste takes the form of spent or useless materials generated from households and businesses, construction and demolition processes, and manufacturing and agricultural industries. These materials are loosely categorized as municipal solid waste, construction and demolition (C&D) debris, and industrial or agricultural by-products.[20]Sustainable architecture focuses on the on-site use ofwaste management, incorporating things such asgrey watersystems for use on garden beds, andcomposting toiletsto reduce sewage. These methods, when combined with on-site food waste composting and off-site recycling, can reduce a house's waste to a small amount of packaging waste.This is the new techniques of sustainable architecture .Building placement[edit]This sectiondoes notciteanyreferences or sources.Please help improve this section byadding citations to reliable sources. Unsourced material may be challenged andremoved.(March 2011)

One central and often ignored aspect of sustainable architecture is building placement. Although the ideal environmental home or office structure is often envisioned as an isolated place, this kind of placement is usually detrimental to the environment. First, such structures often serve as the unknowing frontlines ofsuburban sprawl. Second, they usually increase theenergy consumptionrequired for transportation and lead to unnecessary auto emissions. Ideally, most building should avoid suburban sprawl in favor of the kind of lighturban developmentarticulated by theNew Urbanistmovement. Careful mixed use zoning can make commercial, residential, and light industrial areas more accessible for those traveling by foot, bicycle, or public transit, as proposed in thePrinciples of Intelligent Urbanism. The study ofPermaculture, in its holistic application, can also greatly help in proper building placement that minimizes energy consumption and works with the surroundings rather than against them, especially in rural and forested zones.Sustainable building consulting[edit]A sustainable building consultant may be engaged early in the design process, to forecast the sustainability implications ofbuilding materials, orientation, glazing and other physical factors, so as to identify a sustainable approach that meets the specific requirements of a project.Norms and standards have been formalized by performance-based rating systems e.g.LEED[21]andEnergy Starfor homes.[22]They definebenchmarksto be met and providemetricsand testing to meet those benchmarks. It is up to the parties involved in the project to determine the best approach to meet those standards.Changing pedagogies[edit]Critics of the reductionism of modernism often noted the abandonment of the teaching of architectural history as a causal factor. The fact that a number of the major players in the shift away from modernism were trained at Princeton University's School of Architecture, where recourse to history continued to be a part of design training in the 1940s and 1950s, was significant. The increasing rise of interest in history had a profound impact on architectural education. History courses became more typical and regularized. With the demand for professors knowledgeable in the history of architecture, several PhD programs in schools of architecture arose in order to differentiate themselves from art history PhD programs, where architectural historians had previously trained. In the US,MITandCornellwere the first, created in the mid-1970s, followed byColumbia,Berkeley, andPrinceton. Among the founders of new architectural history programs wereBruno Zeviat the Institute for the History of Architecture in Venice, Stanford Anderson and Henry Millon at MIT, Alexander Tzonis at theArchitectural Association, Anthony Vidler at Princeton,Manfredo Tafuriat the University of Venice,Kenneth FramptonatColumbia University, and Werner Oechslin and Kurt Forster atETH Zrich.[23]The term sustainability in relation to architecture has so far been mostly considered through the lens of building technology and its transformations. Going beyond the technical sphere of green design, invention and expertise, some scholars are starting to position architecture within a much broader cultural framework of thehuman interrelationship with nature. Adopting this framework allows tracing a rich history of cultural debates about our relationship to nature and the environment, from the point of view of different historical and geographical contexts.[24]Sustainable urbanism and architecture[edit]Concurrently, the recent movements ofNew UrbanismandNew Classical Architecturepromote a sustainable approach towards construction, that appreciates and developssmart growth,architectural traditionandclassical design.[25][26]This in contrast tomodernistandglobally uniformarchitecture, as well as leaning against solitaryhousing estatesandsuburban sprawl.[27]Both trends started in the 1980s. TheDriehaus Architecture Prizeis an award that recognizes efforts in New Urbanism and New Classical Architecture, and is endowed with a prize money twice as high as that of the modernistPritzker Prize.[28]Criticism[edit]There are conflicting ethical, engineering, and political orientations depending on the viewpoints.[29]

WHAT IS SUSTAINABLE CONSTRUCTION?Sustainable construction aims at reducing the environmental impact of a building over its entire lifetime, while optimizing its economic viability and the comfort and safety of its occupants.

SUSTAINABLE BUILDING MATERIALS

Dimensional Lumber

DEFINITION:Dimensional lumber refers to the wood used in constructing the wall, floor and roof framing of a house.

CONSIDERATIONS:Most U.S. homes are constructed with wood framing. Although wood is a renewable resource, the amount of wood required for construction purposes is taxing the regenerative capabilities of this resource, as well as depleting a critical component in ecological balance. Trees affect water quality, rainfall, and air quality, both in the immediate region and on a global scale.Although the status of the wood resource is hotly debated, it is clear that expanding demand simply due to population growth has or will have an impact on its long term viability. The reduction of primary forest cover has spurred further debate on the management of the forests as balanced ecosystems. Some new management approaches are based upon holistic sustainable principles. The principles of sustainability which underpins the Green Builder Program favors forest management practices that retain natural forest ecosystems.Some of the options associated with this approach are difficult to implement. There are very few certified sustainably managed wood sources and certifying groups are still in the process of determining universal guidelines for certification. The active certifying organizations, listed at the end of this section, have developed strong ecologically based criteria. Wood certified by the groups mentioned in this section meets the criteria of the Green Builder Program.Wood from old growth forests is not identified in final products, making the option of avoiding it very difficult. Most of the old growth trees are in Redwood and Douglas Fir regions; however, wood of these species exists that is not from old growth areas.Southern wood species such as Yellow Pine are harvested in Texas. Using a regional species can provide an economic benefit to the state and to our area. The growth/removal rate for Yellow Pine looks positive for the future; although increased demand could cause problems. The increased use of engineered wood from all species reduces waste and is beneficial. Additionally, using smaller dimensional wood (less than 210) allows smaller trees to be used which can be helpful in tree farming rotations (common to Yellow Pine).CommercialStatusImplementationIssues

TECHNOLOGYSUPPLIERSCOSTFINANCINGACCEPTANCEREGULATORY

Southern Softwood

Large Dimension

Old Growth

Certified

Legend

Satisfactory

Satisfactory in most conditions

Satisfactory in Limited Conditions

Unsatisfactory or Difficult

COMMERCIAL STATUSTECHNOLOGY:The ability to identify old growth wood in lumber is not standardized. Certified wood is just beginning to be available on a national basis. The use of southern softwoods and smaller dimensional wood is standard.SUPPLIERS:Suppliers of Yellow Pine wood species and smaller dimensioned lumber are common. Suppliers of certified wood are rare on a national basis and not available locally.COST:Yellow Pine is competitively priced. Certified wood must be special ordered and shipped from limited out of state sources. Unless ordered in large volume, the costs will be higher than standard lumber.

IMPLEMENTATION ISSUESFINANCING:Available, as long as code requirements are met.PUBLIC ACCEPTANCE:Wood resource issues are not well known by the general public. Certified wood will appeal to a small number of people.REGULATORY:Structural lumber must be graded and applied according to design values established by ASTM standards.

GUIDELINESThe framing materials discussed in this section have standard installation and construction requirements.Certified wood has become more available over time. Certification organizations should indicate an association with the Forest Stewardship Council (an international coalition promoting a common set of principles and guidelines used to evaluate certifying organizations).

Wood TreatmentDEFINITION:Wood treatment refers to protecting wood from damage caused by insects, moisture, and decay fungi.

CONSIDERATIONS:Three primary methods of wood treatment currently prevail: creosote pressure-treated wood, pentachlorophenol pressure-treated wood, and inorganic arsenical pressure-treated wood. The pressure-treating process is done by commercial facilities and made available to users in the final wood product. Copper napthenate, zinc napthenate, and tributyltin oxide are other wood treatment options that can be site applied. All of these treatment processes involve dangerous chemicals .Chromated copper arsenate (CCA) is the most popular wood treatment product available today. The chemicals are inert within the material and offer protection from moisture and decay fungi. The chemicals do not penetrate into the heartwood effectively so a sealer is advisable on cut ends of CCA treated wood. Although CCA treated wood is sawn on jobsites, hardly anyone seals the cuts. All pressure treated products require adherence to safety precautions approved by the EPA. The safety precautions are listed in the Guidelines section.EPA regulations govern the manufacture of pressure-treated materials and require extensive environmental safety precautions. Wood treatment does offer a method to extend the usable life of our wood resources.The toxicity of the chemicals used in wood treatment has led to research into less toxic methods such as the use of borates derived from the natural element boron (borax). Borates (from boron) are used in wood in New Zealand and Australia and offer insect protection and fire retarding benefits to wood. Full-scale commercial introduction of borates in the U.S. awaits resolution of the leaching problem of borates. Since borates are water soluble, water dilutes them and leaves the wood unprotected from decay after a period of time. In a location unexposed to water, they are effective in preserving wood; site applied borate products are available.Borate pressure-treated wood is being offered by one company in the U.S. (primarily for the Caribbean market). They are promoting the concept of using borates for all the wood in a house. This eliminates the need for termite protection by any other means and prevents decay fungi.Ammoniacal copper quatenary (ACQ) is a new wood preservative currently being introduced. This material employs preservative components that are listed in EPAs classification as General Use pesticides. This is a less toxic material that CCA and it performs similarly.CommercialStatusImplementationIssues

TECHNOLOGYSUPPLIERSCOSTFINANCINGACCEPTANCEREGULATORY

Wood Treatment

Legend

Satisfactory

Satisfactory in most conditions

Satisfactory in Limited Conditions

Unsatisfactory or Difficult

COMMERCIAL STATUSTECHNOLOGY:Borate treatment is not technologically mature in comparison with CCA treated wood. Leaching problems must be resolved for borate treatment to substitute for CCA pressure-treated wood.SUPPLIERS:Suppliers of site-applied borate products are uncommon. Commercial application of borate treatment is just becoming available.COST:Site-applied borate treatments exceed the cost of other chemical treatments due to shipping costs. Borate pressure-treated material adds about $2,500 to the costs of an average sized frame house.

IMPLEMENTATION ISSUESFINANCING:Available if the borate treatment is code compliant.PUBLIC ACCEPTANCE:There is not widespead awareness of borate treatment. However, reduced health risk should be seen as a positive characteristic.REGULATORY:Any wood within 6 inches of the finish grade must be factory treated or have natural resistance (e. g. heartwood of cedar, redwood, or black locust). (See alsoNon-toxic Termite Control)

GUIDELINES1.0 PrecautionsIt is required that this information be available to persons using Inorganic Arsenical Pressure-Treated Wood (CCA), Pentachlorophenol Pressure-Treated Wood, Creosote Pressure-Treated Wood.1.1 Generic Precautions for all three typesDo not use treated wood under circumstances where the preservative may come in contact with food or animal feed, like food containers.Do not use treated wood for cutting-boards or countertops.Only treated wood that is visibly clean and free of surface residue should be used for patios, decks and walkways.Do not use treated wood for construction of those portions of beehives which may come into contact with the honey.Treated wood should not be used where it may come into direct or indirect contact with public drinking water, except for uses involving incidental contact such as docks and bridges.Dispose of treated wood by ordinary trash collection or burial. Treated wood should not be burned in open fires or in stoves, fireplaces or residential boilers because toxic chemicals may be produced as part of the smoke or ashes. Treated wood from commercial or industrial use (e.g., construction sites) may be burned only in commercial or industrial incinerators or boilers in accordance with state and federal regulations.Avoid frequent or prolonged inhalation of sawdust from treated wood. When sawing and machining treated wood, wear a dust mask. Whenever possible, these operations should be performed outdoors to avoid indoor accumulations or airborne sawdust from treated wood.When power-sawing and machining, wear goggles to protect eyes from flying particles.Wash exposed areas thoroughly after working with the wood and before eating, drinking and use of tobacco products.If preservatives or sawdust accumulate on clothes, launder before reuse. Wash work clothes separately from other household clothing.1.2 Additional Precautions for Inorganic Arsenical Pressure-Treated Wood (CCA)Wood pressure-treated with waterborne arsenical preservatives may be used inside residences as long as all sawdust and construction debris are cleaned up and disposed of after construction.1.3 Additional Precautions for Pentachlorophenol Pressure-Treated WoodLogs treated with pentachlorophenol should not be used for log homes.Wood treated with pentachlorophenol should not be used where it will be in frequent or prolonged contact with bare skin (for example, chairs and other outdoor furniture), unless an effective sealer has been applied.Pentachlorophenol-treated wood should not be used in residential, industrial or commercial interiors except for laminated beams or for building components which are in ground contact and are subject to decay or insect infestation, and where two coats of an appropriate sealer are applied. Sealers may be applied at the installation site.Wood treated with pentachlorophenol may be used in the interiors of farm buildings which are in ground contact and are subject to decay or insect infestation and where two coats of an appropriate sealer are applied except where there may be direct contact with domestic animals or livestock which may crib (bite) or lick the wood. Sealers may be applied at the installation site.Do not use pentachlorophenol-treated wood for farrowing or brooding facilities.Do not use pentachlorophenol-treated wood where it may come into direct or indirect contact with drinking water for domestic animals or livestock, except for uses involving incidental contact such as docks and bridges.Urethane, shellac, latex, epoxy, enamel and varnish are acceptable sealers for pentachlorophenol-treated wood.1.4 Additional Precautions for Creosote Pressure-Treated WoodWood treated with creosote should not be used where it will be in frequent or prolonged contact with bare skin (for example, chairs and other outdoor furniture), unless an effective sealer has been applied.Creosote-treated wood should not be used in residential interiors. Creosote-treated wood may be used in interiors of industrial building components which are in ground contact and are subject to decay or insect infestation. For such uses, two coats of an appropriate sealer must be applied. Sealers may be applied at the installation site.Creosote-treated wood may be used in interiors of farm buildings for building components which are in ground contact and are subject to decay or insect infestation, and if two coats of an effective sealer are applied except where there may be direct contact with domestic animals or livestock which may crib (bite) or lick the wood. Sealers may be applied at the installation site.Do not use creosote-treated wood for farrowing or brooding facilities.Do not use creosote-treated wood where it may come into direct or indirect contact with drinking water for domestic animals or livestock, except for uses involving incidental contact such as docks and bridges.Avoid frequent or prolonged skin contact with creosote-treated wood; when handling the treated wood, wear long-sleeved shirts and long pants and use gloves impervious to the chemicals (for example, gloves that are vinyl-coated).Coal tar pitch and coal tar pitch emulsion are effective sealers for creosote-treated wood block flooring. Urethane, epoxy, and shellac are acceptable sealers for all creosote-treated wood.2.0 Borate site-applied products2.1 Impel RodsAvailable in various sizes in a glass rod.Holes are drilled in the wood and the rods are inserted according to manufacturers calculations that considers the size of the wood and the amount of boric acid needed to protect the wood.The rods contain boric acid that is absorbed by the wood when the moisture content of the wood exceeds 25%. The boric acid penetrates heartwood and sapwood stopping decay. When wood is dry the boric acid is inactive.Example: In logs, of 8 inch diameter, one rod per linear foot is needed (rod size is 3/4x3)2.2 Auro Borax Wood Impregnation No. 111Effective against fungus, preventive against insects, suitable for brush application, spray application, or dipping.Must be diluted according to method of application, type of wood, and wood moisture content.Is corrosive in solution.2.3 Tim-BorAvailable in a powder form.Can be applied to wet lumber (over 20% moisture).Can be dipped or sprayed.2.4 Bora-CareAvailable in a liquid form.Includes a glycol solution that helps diffusion.Can be dipped or sprayed.3.0 ACQUsed the same as CCA preserved material.Currently unavailable in Texas and is more costly than CCA.4.0 CCAAvailable as Type A, B, and C. Type C is recommended as superior in resisting leaching.CCA preserved wood does not properly fix in wood in cold weather. If buying CCA treated wood in the winter (and the wood was treated in the winter), use extra care in handling and applying since leaching of the CCA is possible, posing an environmental and health risk. When buying CCA treated wood in warm weather (above 70 degrees ), the chemicals should be fixed in the wood in 3-4 days.Protect CCA wood with a sealer from UV degradation.5.0 Other Chemical TreatmentsACA (ammoniacal copper arsenate); ACZA (ammoniacal copper zinc arsenate); ACC (acid copper chromate); CZC (chromated zinc chloride). These lesser known water borne preservatives are used in hard-to-penetrate woods. Safety precautions are needed.6.0 Decay resistant domestic woodsAlong with cedar and redwood, the following woods are considered resistant or very resistant to decay: bald cypress (old growth), catalpa, black cherry, chestnut, Arizona cypress, junipers, black locust, mesquite, red mulberry, burr oak, chestnut oak, gambrel oak, Oregon white oak, post oak, white oak, osage orange, sassafras, black walnut, Pacific yew.7.0 Borate Pressure-Treated LumberOne supplier currently in United States. (see Resources).Any wood engineered, sheathing, dimensional can be treated by this method.When all wood is treated in house, it will add approximately $2500 to cost.Eliminates need for termite treatments and maintenance calls.Penetrates heartwood (CCA does not).Non-toxic for handling, cutting, and disposal.Does not need to be site-treated on cut ends (CCA does).Cannot be used in ground or water contact.

Engineered Structural Materials

DEFINITION:Engineered structural products are recycled/reconstituted wood materials that employ laminated wood chips or strands and fingerjointing (the gluing of larger pieces together).

CONSIDERATIONS:These materials fall into the general category of engineered wood. This means that the tolerances in stability, consistency, straightness, and strength are more precise than dimensional lumber, making the products easier to work with. In joist and rafter applications, the reconstituted products are particularly useful for long spans without bowing or lateral movement.These materials drastically minimize the amount of waste created in processing the raw materials. Waste wood and entire trees, regardless of species, shape, and age, can be used in making these products.Fingerjointed studs reduce waste in two ways. Short pieces that normally would be unusable are combined rather than disposed and the engineered quality of fingerjointed materials eliminate warping or cracking. The strength of the joints in good quality material is such that the solid wood portions will be more likely to break than the adhered fingerjoint.CommercialStatusImplementationIssues

TECHNOLOGYSUPPLIERSCOSTFINANCINGACCEPTANCEREGULATORY

Recycled/Reconstituted Wood

Satisfactory

Satisfactory in most conditions

Satisfactory in Limited Conditions

Unsatisfactory or Difficult

COMMERCIAL STATUSTECHNOLOGY:Well developed.SUPPLIERS:Dealers exist in Austin for I-beams and laminated materials and all local suppliers can order these materials. Fingerjointed structural material is not readily available locally.COST:Mostly equal to solid sawn wood. When labor savings and reduced job site waste are considered, the cost is highly competitive. Engineered wood products should be more stable in price than dimensional lumber.

IMPLEMENTATION ISSUESFINANCING:Available.PUBLIC ACCEPTANCE:Environmentally aware and/or quality conscious individuals may prefer these materials. Not objectionable to the general public, however.REGULATORY:None, when used to manufacturers approved specifications.

GUIDELINES1.0 I-BeamsReconstituted web material, typically of OSB (oriented-strand board), and solid wood flanges.Flanges should not be cut or notched.Should be stored on edge in a vertical position.Blocking or stiffeners will be needed in ridges, cantilevers, and other specific load bearing locations.2.0 Laminated BeamsCan be nailed or bolted together to form multiple member beams for heavy load requirements.3.0 Fingerjointed studsMay replace conventional studs; will not twist.

Engineered Sheet Materials

DEFINITION:Engineered sheet materials can be made of recycled-content or reconstituted materials.Recycled content sheet products include any percentage of recycled material. Products that use recycled newsprint, agricultural byproducts, or wood waste are considered recycled content materials.Reconstituted materials use chipped or stranded small-diameter trees as their wood source. This material is then bound together into forms suitable for building.

CONSIDERATIONS:Products exist that contain recycled post-consumer paper, by-product gypsum and recovered gypsum, wood waste, wood chips from non-commercial trees, and annually-renewable agricultural fibers. These materials include: hardboard made from waste wood; wallboard made from perlite, gypsum, and recycled post-consumer newsprint; 100% recycled newsprint fiberboard; and fiberboard made from straw.Some of these materials need to be kept dry during the construction process. Binders used in some of these materials may outgas. It is best to avoid materials that contain urea formaldehyde. Phenol formaldehyde is predominantly used in materials for exterior applications. where its lower outgassing qualities are not considered health threatening.. Most of these materials are installed/applied in the same manner as the traditional products (plywood), therefore labor estimates are comparable. Oriented-strand board (OSB) is a reconstituted material that is now commonly used.CommercialStatusImplementationIssues

TECHNOLOGYSUPPLIERSCOSTFINANCINGACCEPTANCEREGULATORY

Subflooring

Sheathing

Wallboard

Agricultural By-Product

Decking

Satisfactory

Satisfactory in most conditions

Satisfactory in Limited Conditions

Unsatisfactory or Difficult

COMMERCIAL STATUSTECHNOLOGY:Many of these technologies are relatively simple; gypsum has been recycled and reused for many years and newsprint recycling is also a mature technology. Most of these products, such as oriented strand board, are derived from manufacturing processes which are more material-efficient than past processes. Much of the newer recycled-content and reconstituted materials are fabricated in modern facilities that are efficient and compliant with strict environmental regulations.SUPPLIERS:Few of these products, other than OSB and laminated wastepaper sheathing, are currently available locally.COST:Many of these sheet materials currently cost more then traditional sheet materials, although the oriented strand board and laminated wastepaper sheathing are price competitive. Shipping costs for small quantities can be prohibitively expensive.

IMPLEMENTATION ISSUESFINANCING:Available.PUBLIC ACCEPTANCE:Acceptance of these products is good. When oriented-strand board products first appeared on the market, many people confused them with particle board ( an indoor use only product) because of its similar appearance. The negative reaction stemming from this confusion has been overcome. These products are comparable in appearance with the ones they replace, and since they are covered in places where they are used, their appearance ceases to be an issue. There is a high appreciation and an increasing demand for least-toxic products. The recycled-content of these materials enhances their appeal.REGULATORY:Meets code requirements.

GUIDELINESMost of these materials come in standard dimensions, are applied with standard fasteners, and can be worked with regular carpentry tools.Some products might require specific structural spacing and support. This information is supplied by the manufacturer.Some of the interior finish sheet product alternatives to gypsum sheetrock do not require taping and floating.Look for the recycling symbol on theses products.100% recycled content is available in some foil-backed materials.Comments regarding specific products are found in the Resources section where they are listed.

Engineered Siding

DEFINITION:Engineered materials refer to the more efficient (less wasteful) process of using wood or other cellulose fibers bonded together to make a material shape. Reconstituted materials are more dense and offer increased longevity. Some products have wood fibers mixed with cement to form extremely durable exterior (fiber-cement) materials.Fingerjointed material consists of using shorter pieces of wood glued together to make a longer piece. This technology makes use of wood that could previously be considered waste.Recycled-content materials include substances that are salvaged from the waste stream such as sawdust and paper.Tropical hardwood refers to wood harvested from the tropical forests that are being harvested in a destructive manner.Recycled trim refers to the reuse of trim salvaged from building demolition.

CONSIDERATIONS:Reconstituted and recycled-content (engineered) siding materials offer superior longevity over wood siding. The increased density of the materials resists cracking and other deterioration. Fiber-cement materials, for example, offer very long warranties and have zero flamespread.Steel and aluminum siding materials are predominantly fabricated from recycled material. Although the embodied energy is high when the materials are originally made, they require much less energy in a recycled form. They can also be recycled again after use in a building.The use of domestic hardwoods for moldings and trim is noted since domestic hardwood trees are maturing at a faster rate than they are being removed (positive growth-removal rate).Using recycled trim reuses trim in its same form, achieving the most resourceful recycling. Since trim is not structural, it is acceptable to use it in new construction. It will require going to different sources for material such as salvage businesses, and finding a large enough quantity of the same style can be challenging.A very small percentage of tropical wood is sustainably managed and most of that is being used in furniture. The Resources section will note tropical species that are being sustainably managed.There is not a problem with weak points in quality fingerjointed materials. For aesthetic reasons, fingerjointed material would go best where it will be painted.CommercialStatusImplementationIssues

TECHNOLOGYSUPPLIERSCOSTFINANCINGACCEPTANCEREGULATORY

Siding

Trim

No Tropical Hardwood

Fingerjointed Trim

Domestic Hardwood

Recycled Trim

Reconstituted Trim

Satisfactory

Satisfactory in most conditions

Satisfactory in Limited Conditions

Unsatisfactory or Difficult

COMMERCIAL STATUSTECHNOLOGY:The technology involved with these items is well-developed. There will be more reconstituted/recycled content materials entering the market.SUPPLIERS:Recycled-content materials are available primarily in aluminum. Reconstituted materials are available primarily in hardboards. All trim options are available including recycled trim. Fiber-cement siding is available.COST:Competitive.

IMPLEMENTATION ISSUESFINANCING:There is not a financing issue.PUBLIC ACCEPTANCE:Highly durable engineered siding products are desirable.REGULATORY:Exterior wall coverings code regulations are presented in the 1992 CABO code Section R-503. Products purchased for siding must be installed according to the manufacturers instructions.

GUIDELINESFiber-cement materials can be worked with woodworking tools.Fiber-cement materials need an alkali resistant paint when painted. Some fiber-cement materials can be used unpainted if handled carefully to avoid scratching.Fiber-cement materials are not brittle like earlier asbestos products.Comments on products are included in the Resources Section.

Flyash Concrete

DEFINITION:Flyash is defined in Cement and Concrete Terminology (ACI Committee 116) as the finely divided residue resulting from the combustion of ground or powdered coal, which is transported from the firebox through the boiler by flue gases. Flyash is a by-product of coal-fired electric generating plants.Two classifications of flyash are produced, according to the type of coal used. Anthracite and bituminous coal produces flyash classified as Class F. Class C flyash is produced by burning lignite or subbituminous coal. Class C flyash is preferable for the applications presented in the Green Building Guide and is the main type offered for residential applications from ready-mix suppliers.

CONSIDERATIONS:Flyash is one of three general types of coal combustion byproducts (CCBPs). The use of these byproducts offers environmental advantages by diverting the material from the wastestream, reducing the energy investment in processing virgin materials, conserving virgin materials, and allaying pollution.Thirteen million tons of coal ash are produced in Texas each year. Eleven percent of this ash is used which is below the national average of 30 %. About 60 70% of central Texas suppliers offer flyash in ready-mix products. They will substitute flyash for 20 35% of the portland cement used to make their products.Although flyash offers environmental advantages, it also improves the performance and quality of concrete. Flyash affects the plastic properties of concrete by improving workability, reducing water demand, reducing segregation and bleeding, and lowering heat of hydration. Flyash increases strength, reduces permeability, reduces corrosion of reinforcing steel, increases sulphate resistance, and reduces alkali-aggregate reaction. Flyash reaches its maximum strength more slowly than concrete made with only portland cement. The techniques for working with this type of concrete are standard for the industry and will not impact the budget of a job.This section also addresses wall-form products. Most of these products have hollow interiors and are stacked or set in place and then filled with steel-reinforced concrete creating a concrete structure for a house.Some wall-form materials are made from EPS (expanded polystyrene) which is a lightweight non-CFC foam material. There are also fiber-cement wall-form products that can contain wood waste. The EPS/concrete systems offer high insulating qualities and easy installation. The fiber-cement blocks offer insulating qualities as well. Some EPS products also have recycled content.CommercialStatusImplementationIssues

TECHNOLOGYSUPPLIERSCOSTFINANCINGACCEPTANCEREGULATORY

Cementitous Structure

Flyash Concrete

Recycled Content Block

Concrete Finish Floor

Concrete Interior Wall

Satisfactory

Satisfactory in most conditions

Satisfactory in Limited Conditions

Unsatisfactory or Difficult

COMMERCIAL STATUSTECHNOLOGY:Flyash used in concrete is a mature technology. Thirty percent of the flyash in the US is recycled into making concrete. The use of flyash concrete in structural applications such as wall-forms is standard technology. The use of recycled-content block, in particular fiber-cement, as part of a structural foundation system using flyash concrete is still early in development.SUPPLIERS:Approximately 60-70% of central Texas ready-mix suppliers offer flyash concrete. Some suppliers provide it automatically, others give a choice. Recycled-content fiber-cement block should become more available as a regional distributor has been established. EPS wall-form materials are locally and regionally available.COST:Flyash concrete is the same price as ordinary concrete without flyash. EPS wall-form products provide a cost-effective wall. Fiber-cement wall-form cost approximately $3.50 per square foot of wall surface.

IMPLEMENTATION ISSUESFINANCING:Available.PUBLIC ACCEPTANCE:There is a small segment of the population that is fearful of flyash being inferior or unhealthful. U.S. EPA information indicates there is not a health threat, especially in the portions found in ready-mix products and with western coal (which is the primary source of local flyash).A concrete finish floor may sound less desirable aesthetically to some persons. However, coloring, scoring, and texturing techniques can be very attractive.Wall-form products should be well-received.REGULATORY:Flyash concrete meets applicable codes. Products making use of flyash concrete must indicate having met applicable ASTM test requirements. This information will be provided by the supplier.

GUIDELINES1.0 Specification for flyashFlyash for use in portland cement concrete shall conform to the requirements of ASTM C 618, Standard Specification for Flyash and Raw or Calcined Natural Pozzolan Class C Flyash for use as a Mineral Admixture in Portland Cement. Specifically, it shall conform to all requirements of Table 1 and Table 2 as outlined therein.The concrete supplier shall furnish a notarized certificate from the flyash marketer at the time of submittal of concrete mix designs for approval indicating conformance with these requirements. Also, a copy of the most recent chemical analysis shall be provided.At no time during the course of the project will a change of flyash source (plant) be permitted without the prior written consent of the Engineer or Architect. For sulfate environments, only Class F flyash will be permitted and under no circumstances will Class C flyash be used.2.0 Flyash use.Class F flyash will typically require an air entraining agent to be added. Class C flyash will not.Standard concrete procedures can be employed.3.0 Flyash concrete in poured concrete permanent wall-formsThe use of these systems eliminates the need for conventional framing on exterior walls.Expanded polystyrene (EPS) wall-formsSome feature interlocking features and stack like blocks. Some are in rigid panels on interior and exterior connected by metal or steel ties.EPS blocks are typically stacked as exterior walls. Rebar is placed in the cores vertically and horizontally. The cores are poured full of concrete from the top.Manufacturers claim R-values of R-30 or greater.Specify that the foam is protected from insects. Insects will not eat the foam but will nest in it. Borate treatment is preferable.Urethane block wall-form products are also available. These contain CFCs/HCFCs.Fiber-cement wall forms.Can use waste wood; will not burn; insect resistant; will not support condensation.Approximately R-12 ratings in 9 inch block.Hollow cores are filled with steel reinforced concrete.

Non Toxic Termite Control

DEFINITION:Non-toxic termite control is the use of termite prevention and control without chemical use. Instead, physical controls are installed during construction such as sand barriers or metal termite shields. If termite infestation does occur, least toxic methods of treatment are used.

CONSIDERATIONS:Most areas of Texas have termites. These include subterranean termites that live in the soil and drywood termites that attack dry wood. According to the Texas Agricultural Extension Service, there is a greater than 70 percent probability that wooden structures in Texas will be attacked by termites within 10 to 20 years. Termite problems within one year after construction have been reported.When wood is used as a building material, termite prevention in the form of treated wood or naturally resistant wood will be required by building codes. Typically, chromated copper arsenate (CCA) pressure-treated wood is used. Two alternative chemical substances have gained popularity as more toxic substances such as chlordane have been banned for soil treatment. These include organophosphates and pyrethroids. However, these chemicals are toxic to people as well as termites, and can offgas and leach out into the soil and water table. They can be absorbed through the skin, lungs and through ingestion. Exposure to small children, workers, chemically-sensitive individuals and animals can lead to serious health problems.Less toxic wood treatments are available. (SeeWood TreatmentSection.) However, alternatives to wood treatment and chemical treatment can be quite effective. Least-toxic strategies must be used in combination to achieve maximum effectiveness. Few pest control managers expect non-toxic methods to completely replace chemical use. However, they offer considerable potential for the reduction of chemical use, and may prevent such use in all but extreme situations.CommercialStatusImplementationIssues

TECHNOLOGYSUPPLIERSCOSTFINANCINGACCEPTANCEREGULATORY

sand barrier, termite shields

Satisfactory

Satisfactory in most conditions

Satisfactory in Limited Conditions

Unsatisfactory or Difficult

COMMERCIAL STATUSTECHNOLOGY:Research and monitoring is underway to test the effectiveness of non-toxic termite prevention techniques. The USDA Southern Forest Experiment Station in Gulfport, Mississippi, and the University of Hawaii are doing research. Successful laboratory results have been obtained with the use of properly designed sand barriers. Pest control professionals in California have adapted and tested sand barriers with good results. Some studies in California have found some physical barriers to be 15% more effective than chemical treatments.SUPPLIERS:There are architects and pest management companies in Austin that can provide expertise and services in non-toxic termite prevention and control. However, not all professionals currently have knowledge or experience with non-toxic termite control.COST:Initial costs of non-toxic termite prevention may be 25% higher than chemical controls. However, these costs may be offset due to the long term nature of structural solutions. In addition, cost offsets can occur if traditional fill material is replaced with sand or cinder barriers, preventing the need for termiticides.

IMPLEMENTATION ISSUESFINANCING:Lenders will typically look for traditional methods for the prevention of termites, such as the use of treated wood. Educating lenders about the effectiveness of non-toxic prevention measures and encouraging financing incentives for their use is a goal of the Green Builder Program.PUBLIC ACCEPTANCE:For successful termite prevention using non-toxic methods, education and cooperation between the professional and the resident/owner will be necessary. Increased monitoring after construction will be necessary.REGULATORY:Building codes (such as Section R-310 of the CABO One and Two Family Dwelling Code) call for protection by chemical soil treatment, pressure-treated wood, naturally termite-resistant wood (such as heartwood of redwood and eastern red cedar), or physical barriers approved by the building official in areas with subterranean termites. Approved combinations of methods may be used.For decay prevention, any wood (siding, trim, framing) within 6 inches of the finished grade must be protected. Additionally, wood girders within 12 inches, wood structural floor within 18 inches, and wood sills on masonry slabs within 8 inches must also be protected. Decay prevention and termite protection are addressed jointly with wood treatment and naturally resistant wood. Structural controls for termites such as sand barriers and termite shields will not eliminate the need for decay prevention in wood within the distances from the ground mentioned above.The Honolulu building code was rewritten in 1991 to include the use of sand barriers instead of chemical controls. The City of Austin will examine precedents accepted by other jurisdictions on a case-by-case basis.

GUIDELINESAny pest management program that uses the principles of Integrated Pest Management (IPM), or least toxic methods, will have the following components: Integration of least-toxic treatment methods and materials; Monitoring; Detection and identification.No method of termite treatment can be assumed to be 100% effective. In homes with wood as a construction material, regular inspections should be performed, regardless of treatment and prevention methods. The best method is non-toxic prevention, however there are also non-toxic treatment methods if termites are found.1.0 PreventionThe only sure prevention of termite problems is the use of building materials other than wood. However, if wood is used, there are preventative measures available to the builder other than chemical treatments and treated wood products. A common tree in Austin known to resist termites is the familiar mountain cedar (actually a member of the juniper family). Although not commercially lumbered, natural cedar posts have traditionally been used as foundation piers on old structures, and extensively for fences and furniture. The use of juniper wood has some potential for application as a termite and insect resistant wood.Eliminating sources of chronic moisture in the home is one of the most important factors in managing subterranean termites, carpenter ants, and some wood boring beetles. Moist soil is necessary for termites to survive. Termites travel back and forth between soil and food sources because they must obtain moisture from the soil. In addition, capillary action and water vapor buildup can result in excessive dampness which can actually wick through a concrete slab or masonry foundation to the wood framing above it, thus attracting termites.In above-ground foundations, moisture barrier films such as 6 mil polyethylene can be used to cover the area under the structure. This will help decrease moisture buildup in sub-flooring. Foundation wall vents should be placed to provide cross ventilation for homes with crawl spaces. If re-grading or remodeling covers vents, additional vents may be needed. Some experts recommend the use of moisture barriers under slab foundations as well.Soil should always be from 6 to 18 inches below any wood member, the greater the distance, the better. Good siting and drainage design will help to prevent moisture buildup in and around the structure. All exterior grades should slope away from the structure to provide drainage. Porches and features such as planter boxes should be constructed and sealed to prevent moisture and soil contact with the structure.Exterior landscaping should not cause moisture build-up around the foundation. A small air space should be retained between plant leaves and walls to prevent moisture and mold build-up. Automatic irrigation heads should be properly aligned or shielded to prevent direct spray onto the building.Areas subject to moisture build-up, such as bathrooms, should be given special attention since they are likely to be attack areas. Areas under tubs and drains leading to the exterior (such as air conditioner drains) should be considered vulnerable spots.All wood-to-soil and wood-to-concrete contacts should be eliminated for fence and deck posts, rail supports, and trellises etc. Posts should be placed in metal holders (commercially available). Even treated deck piers may not deter termites since they may bypass the treated piers to reach untreated decking above.All wood subject to moisture, especially exterior wood, should be properly sealed. Exterior windows, even if under an overhang such as a porch, should be completely moisture sealed. Exterior siding, especially along the bottom wall edges, should be completely moisture sealed on all exposed surfaces.All lumber scraps, wood debris and stumps should be removed from the site after construction is complete. Backfill under a foundation should never contain wood scraps, and scrap should never be left in crawlspaces or under foundations. Such scraps are invitations to termites to eat first the scrap and then move on to the main structure.2.0 Sand BarriersSand barriers for subterranean termites are a physical deterrent because the termites cannot tunnel through it. Sand barriers can be applied in crawl spaces under pier and beam foundations, under slab foundations, and between the foundation and concrete porches, terraces, patios and steps. Other possible locations include under fence posts, underground electrical cables, water and gas lines, telephone and electrical poles, inside hollow tile cells and against retaining walls.Sixteen grit sand or cinder is placed in a 20-inch band on the soil surface or in trenches next to foundation walls. The sand layer should be 4 inches thick at the foundation, and feathered out to meet grade at the outer edge of the 20-inch band. For trench installations, trenches should be 4 deep and 6 wide.Some integrated pest management experts have developed a machine, called a sand pump, that blows sand under the house. For sand barriers around the outside perimeter of a foundation, they recommend a sand trench in order to avoid disturbance of the sand. In addition, a cap made of masonry or other materials may be recommended to protect the barrier from gardening, animals, etc. Tamping of sand can be done to increase impermeability to termite attack.2.1 Slab BarriersTermites can easily pass through small cracks, as small as 1/32, which may occur in slab foundations. For sand barriers in conjunction with slab foundations, the sand or cinder must be applied before the foundation is poured. Installing the sand layer of the appropriate mesh size followed by a layer of coarser gravel for grading to the desired level has worked well. To cut costs, sand treatments may be installed in particularly vulnerable areas of the slab, such as around pipe penetrations, as opposed to under the entire slab.Costs for cinder fill under a slab can often be competitive with the costs of standard fill and the initial chemical termite treatment.2.2 Sand SelectionThe size of sand particles is critical to the success of sand barriers. Sand or grit size should be no larger or smaller than that able to sift through a 16-mesh screen. Sand smaller than 16-grit can be carried away by termite workers; larger sand can support tunnel construction by termites. If the sand to be used has some particles smaller than 16-mesh size, sand can be screened with mesh of the appropriate size. Certain grades of sandblasting sand which come in bags may be suitable for barriers. Crushed volcanic cinder of the appropriate size is recommended by some experts.2.3 PerformanceSand barriers can also be used to repair seals that have become broken between foundations and other building elements such as porches. Such settling and breaking of cold joint seals can occur due to subsidence and temperature extremes. In laboratory tests, sand was shown to retain its seal against structural members after movement similar to earthquakes. Although earthquakes are not a problem in our area, soil movement and settling due to expansive soils is often a problem.Use of sand barriers is still experimental, and must be followed with post-installation as well as regular inspections. Sand barriers may cost 25 % more than conventional chemical treatments, however the physical barrier will provide long term protection. Chemical prevention is normally guaranteed for only one year, and introduces toxins into the home environment.3.0 Metal Termite ShieldsMetal termite shields are physical barriers to termites which prevent them from building invisible tunnels. In reality, metal shields function as a helpful termite detection device, forcing them to build tunnels on the outside of the shields which are easily seen. Metal termite shields also help prevent dampness from wicking to adjoining wood members which can result in rot, thus making the material more attractive to termites and other pests.Metal shields are used in conjunction with concrete or solid masonry walls, and are fabricated of sheet metal which is unrolled and attached over the foundation walls. The edges are then bent at a 45 degree angle. Metal shields must be very tightly constructed, and all joints must be completely sealed. Any gaps in the seals will allow an entry point for termites. Joints may be sealed by soldering, or with a tar-like bituminous compound.Metal flashing and metal plates can also be used as a barrier between piers and beams of structures such as decks, which are particularly vulnerable to termite attack.4.0 Monitoring, Detection and IdentificationThe Bio-Integral Resource Center (see Resources, General Assistance) recommends the following steps:1. Monitor the building at least once per year.2. Identify the species of termite.3. Correct structural conditions that led to the infestation.4. Apply physical or biological controls.5. Spot treat with chemicals if necessary.6. Check for effectiveness and repeat if required.Regular termite monitoring should be done with a plan of the structure in hand. This will help to identify inaccessible areas that may be hard to spot with a visual inspection. Annual or bi-annual inspections are recommended.Subterranean termites build characteristic mud tubes for movement between nests. The appearance of these tubes are often the first sign of infestation. Detection can become difficult if such tubes are hidden inside walls, or termites are entering in cracks occurring in concrete slabs or foundations.Dogs are being used by some individuals to aid in termite inspection. These dogs are trained to detect termites and other wood damaging insects, and can provide information about inaccessible areas of the structure. Their keen sense of smell coupled with their ability to wriggle into areas too small for human access can make the dog-assisted inspection a valuable tool.5.0 Termite treatmentThe first step in any termite treatment is accurate identification of the species. Next, location of nests must be found. Next, selection of a combination of least toxic strategies and tactics is necessary.When selecting a pest management company, be sure to choose a reliable firm. Texas law requires commercial pesticide applicators to be certified. Check for certification documentation, references, and work experience, or check with the Structural Pest Control Board of Texas. Ask if the company practices integrated pest management techniques, or has an experimental license which may be necessary for some alternative techniques.Non-toxic treatments include use of nematodes (microscopic worms), especially for chemically-sensitive individuals or environmentally-sensitive areas. Nematodes are pumped into the infested area, where they will kill the insects. Boric acid bait blocks can be placed around the structure, where they will attract the pests to consume termiticides without broad application of chemicals. Drywood termites can be treated with thermal, freezing, or electrical eradication techniques. Desiccating dusts, non-toxic substances resulting in pest dehydration and death, have also been used successfully on drywood termites.These treatments can be combined with others, such as installing metal shields (if they have not been used previously), sealing of broken seals or open areas, and re-grading of soil outside the foundation to improve drainage or create a gap between soil and wood areas such as siding. In addition, termites can be physically removed by trapping or nest excavation.

Earth Materials

DEFINITIONS:The type of materials available locally will of course vary depending upon the conditions in the area of the building site.In many areas, indigenous stone is available from the local region, such as limestone, marble, granite, and sandstone. It mat be cut in quarries or removed from the surface of the ground (flag and fieldstone). Ideally, stone from the building site can be utilized. Depending on the stone type, it can be used for structural block, facing block, pavers, and crushed stone.Most brick plants are located near the clay source they use to make brick. Bricks are molded and baked blocks of clay. Brick products come in many forms, including structural brick, face brick, roof tile, structural tile, paving brick, and floor tile.Caliche is a soft limestone material which is mined from areas with calcium-carbonate soils and limestone bedrock. It is best known as a road bed material, but it can be processed into an unfired building block, stabilized with an additive such as cement. Other earth materials include soil blocks typically stabilized with a cement additive and produced with forms or compression.Rammed Earth consists of walls made from moist, sandy soil, or stabilized soil, which is tamped into form work. Walls are a minimum of 12 thick. Soils should contain about 30% clay and 70% sand.

CONSIDERATIONS:The use of locally available and indigenous earth materials has several advantages in terms of sustainability. They are: Reduction of energy costs related to transportation. Reduction of material costs due to reduced transportation costs, especially for well-established industries. Support of local businesses and resource bases.Care must be taken to ensure that non-renewable earth materials are not over-extracted. Ecological balance within the region needs to be maintained while efficiently utilizing its resources. Many local suppliers carry materials that have been shipped in from out of the area, so it is important to ask for locally produced/quarried materials.Both brick and stone materials are aesthetically pleasing, durable, and low maintenance. Exterior walls weather well, eliminating the need for constant refinishing and sealing. Interior use of brick and stone can also provide excellent thermal mass, or be used to provide radiant heat. Some stone and brick makes an ideal flooring or exterior paving material, cool in summer and possessing good thermal properties for passive solar heating. Caliche block has been produced for applications similar to stone and brick mentioned above. Caliche or earth material block has special structural and finishing characteristics.Rammed earth is more often considered for use in walls, although it can also be used for floors. Rammed earth and caliche block can be used for structural walls, and offer great potential as low-cost material alternatives with low embodied energy. In addition, such materials are fireproof.Caliche block and rammed earth can be produced on-site. It is very important to have soils tested for construction material use. Some soils, such as highly expansive or bentonite soils, are not suitable for structural use. Testing labs are available in most areas to determine material suitability for structural use and meeting codes.Soils for traditional adobe construction are not found in some areas, but other soils for earth building options are available. Many areas have a high percentage of soils suitable for ramming (approximately 19,610 acres in the Austin, TX area, according to the US. Department of Agriculture). Caliche is also abundant in many areas (covering 14 % of the Austin geographic area, for instance) and is readily available locally.CommercialStatusImplementationIssues

TECHNOLOGYSUPPLIERSCOSTFINANCINGACCEPTANCEREGULATORY

Stone

Brick

Caliche

FOUNDATION

Stone

Brick

Caliche

FLOOR

Stone

Brick

Caliche

WALL (A)

Stone

Brick

Rammed Earth

WALL (B)

Legend

Satisfactory

Satisfactory in most conditions

Satisfactory in Limited Conditions

Unsatisfactory or Difficult

COMMERCIAL STATUSTECHNOLOGY:Stone cutting, brick production and masonry techniques are mature technologies. Rammed earth and caliche block construction are not well known by most builders and architects today, although there are some architects and builders who are experienced with these materials.SUPPLIERS:There are numerous suppliers of indigenous stone and local brick in many regions. Caliche block and rammed earth are not available commercially, but can be created on site. There are contractors who can provide machinery for manufacturing compressed soil block, and in some places such block is commercially available.COST:Brick: approximately $2.00 per square foot (4 inch material) and up depending on thickness. Stone: $4.00 to $15.00 per square foot (material) depending on type. Compressed soil block: approximately $1.80 per square foot (9 inches thick). Earth block made from labor intensive methods cost significantly less.

IMPLEMENTATION ISSUESFINANCING:Stone and brick materials do not pose a problem for lending institutions, and are often valued positively for increased property value and fire rating. Rammed earth, compressed soil block, and caliche block may pose problems for traditional financing. Proper testing and building code compliance will assist lenders in accepting their products.PUBLIC ACCEPTANCE:Stone and brick construction are considered desirable, although their use for interior thermal mass is not common in many areas. Rammed earth and caliche block are little known, and may not currently receive wide public acceptance.REGULATORY:In structural applications, materials must be rated for appropriate load requirements. Unfired caliche blocks can easily pass Unified Building Code standards for compression with an average of 960 p.s.i. Rammed earth and caliche block construction will require a building code review if used structurally. Regulatory acceptance will be based on precedents for the material as accepted in other jurisdictions and/or upon independent tests that demonstrate methods and performance required by code for masonry materials are satisfied.

GUIDELINES

1.0 StoneStone construction practices are fairly standard. We do not recommend any stone applications that would require non-traditional methods. Attention needs to be paid to the load capacity of foundations and footings due to the excessive weight of the material. Veneers need non-combustible support such as concrete grade beams or footings. Pay particular attention to grade beams when designing interior stone wall applications. Anchoring of veneers must follow Uniform Building Code (UBC) guidelines.1.2 Indigenous Stone Description Limestone: A rock that is formed chiefly by the accumulation of organic remains (shells or coral), consist mainly of calcium carbonate. Marble: Crystallized limestone, ranges from granular to compact in texture. Granite: A very hard igneous rock formation of visibly crystalline texture formed essentially of quartz and orthoclase or microcline. Sandstone: A sedimentary rock consisting usually of quartz sand combined with some binding elements such as silica or calcium carbonate. Flagstone: A hard, evenly stratified stone that splits into flat pieces suitable for paving. Fieldstone: Stone in unaltered form as taken from the field.

2.0 BrickThe same guidelines in Section 1.0 above also apply to brick masonry.Brick has value as a recyclable material. Used brick, available through local salvage companies, is often desired for its weathered, antique appearance. In addition, brick seconds or brick that is damaged can be crushed and recycled and either returned to the manufacturing process to make more brick, or used as a landscaping material in its crushed form.Some American brick manufacturers are making brick with sewage sludge. Sludge material is mixed with clay normally used in the manufacturing process. The resulting brick is equally attractive and strong. Another alternative material for brick production is petroleum contaminated soils. Such soils, when combined with clay and fired at very high temperatures, yield brick which is free from hydrocarbon contamination.

3.0 Soils for Rammed Earth, Caliche Block, and Soil Material ConstructionSoils that qualify for both Compressed Earth Block and Rammed Earth are common in many areas. Consider that most of the continents are granitic and decomposed granite is normally perfect having the ratios of feldspars to quartz that are appropriate for compaction. Basaltic soils are a little more difficult and many times require additional clay added. The basic formula is 30% clay and the balance loam and small aggregate. Caliche (which is usually a misnomer for decomposed limestone soils) is the common subsoil of the alluvial plain which dominates the south Texas landscape, much of the Midwest and most of the deep south as well as most of the Caribbean . In The Dominican Republic it is named for the coral reefs that underly the island and is somewhat compactable depending on the area. The use of decomposed limestone can be problematic unless modified with either the addition of clay, portland cement or lime if necessary.Soils that are bentonitic or highly expansive are normally unsuitable for earth construction without modification. The shrink and swell capacity of these soils, related to their clay content can cause the block to be highly susceptible to moisture, even high humidity, however the acid test is how the clays actually perform under compaction and even poor performance can be offset by stabilization. Soil cracking after rainfall may indicate expansive soil. Soil must be tested to determine its suitability. The ideal is a block or wall that looks pretty and has a lot of strength but even ugly block and marginal soils can be used to build a structure that will last for centuries.Desirable qualities for soil construction materials include: Strength Low Moisture Absorption Limited Shrink/Swell Reaction High Resistance to Erosion and Chemical Attack Availability3.1 Soil TestingSoil testing techniques vary, and include laboratory as well as field testing. Testing is done in three phases: laboratory testing, construction mix testing, and quality control testing. Laboratory testing should always be done early in the design process, using representative samples of soil intended for use. (See Resources section for laboratories.) Engineering properties for which soils are tested include permeability, stability, plasticity and cohesion, compactibility, durability, and abrasiveness. Shrinkage, swelling and compressive strength are important aspects of soil suitability.Again, it is possible to alter soils to make them suitable for construction by stabilizing them. Stabilizing soil helps to inhibit the shrink and swell potential, and aids in the binding of soil components. Soil can be stabilized through chemical or mechanical means or both. For information on mechanical methods, see Section 5.0 on rammed earth.3.2 Chemical Soil StabilizationLime, portland cement, and other pozzolans (high silica volcanic ash, rice hull ash, etc) can be used as chemical additives. Lime is most effective on clay soils, and can be used in combination with portland cement and pozzolan. Hydrated lime, as opposed to quick lime, should be used. Lime is inexpensive, but care must be taken to protect workers from breathing in lime dust. Cement is relatively inexpensive, but requires large energy inputs in its production process and puts approximately an equal weight of carbon dioxide into the atmosphere. However, cement produces the strongest block and will substitute for clay poor soils where lime will not and the normal usage of between 5 and 10% minimizes the embodied energy especially when compared to concrete and lumber products*. Pozzolan exists in plentiful supply in many areas, and is sometimes readily available commercially in the form of coalfly ash.TheCenter for Maximum Potential Building Systems(CMPBS) in Austin, Tx is experimenting with the use of pozzolan as an additive and offers considerable expertise in earth materials use. See the Resources section.3.3 Strength of tested earth and caliche blockUnfired Compressed Earth Block with addition of 5-10% cement can easily pass the Uniform Building Code standards for compression with an average of 960 psi.Rammed earth walls have been tested with a compressive strength of 30 to 90 psi immediately after forming. Ultimate compressive strength should reach 450-800 psi. If cement is added, compressive strength will increase.The Uniform Building Code for single and two story buildings requires block bearing capacity of 300 psi bearing strength. Blocks manufactured with a hydraulic press have been tested with a bearing capacity immediately after production of 700 psi. Such soil block continues to cure, until blocks reach a typical bearing capacity of 1000 psi., far exceeding requirements of the Uniform Building Code and HUD standards. Cement can be added to the soil block mixture to reach a bearing capacity of 2500-3900 psi.3.4 Soil HandlingThe use of earth as building materials is inexpensive for materials costs, but emphasizes labor in construction methods. The right equipment and coordinated labor are important in the soil material construction process. Even a small structure may require at least 15 tons of earth. This material must be moved and handled at least twice. A front end loader, skidsteer or tractor equipped with a shovel or back hoe will be necessary for on-site extraction of soil materials as well as processing the soil and loading the machinery. A large flat area with good drainage is necessary for handling and processing the materials as well as making the blocks. The building footprint should also be accessible by truck for rammed earth construction.

4.0 Caliche and Soil Block Construction4.1 MaterialsCaliche is used in many areas as a road base material and in the production of cement and lime. Although not commonly used as a building material, there are historical as well as current examples of caliche for construction. For an in-depth treatment of the subject, see The Caliche Report (see Resources). Caliche occurs in abundance in the Austin area and may be possible to get from the construction site. However, if this is not possible, caliche may be purchased from area suppliers. Be sure to test the source. The use of soil as the basic block material is also possible, but will have slightly different stabilization demands.Subsoils are the basics of Earth Block Construction. With a clay content of plus or minus 30% and a water content of 6% (equivalent to soil that has received an inch of rain a week previous. No straw, roots, twigs, leaves, etc.4.2 Block Production MethodsA backhoe and/or a front end loader will be needed to dig the soil on-site or handle soils imported. Soils obtained from the site may need to be dried and screened prior to mixing. Soils should be tested to prove their compactability and to determine any needed additions such as sand or clay. The next step of hydrating and mixing has traditionally been the largest labor and time investment being done either by hand or with a front end loader. The use of concrete and stucco mixers have proven ineffectual for large projects such as a home, however there are earth mixing or blending machinery available that are especially cost effective for adding portland cement or lime and for adding water in dry areas.Sun Dried Adobe Molding techniques may be in the form of monolithic walls (SeeRammed Earth) or molded into blocks or bricks. For the latter, the mix is poured into molds, or pressure molded using special machinery. These methods provide for a variety