Materiaux Final

8/8/2019 Materiaux Final

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INTRODUCTION OF GREEN ARCHITECTURE

Sustainable architecture is a general term that describes environmentally

conscious design techniques in the field of architecture. Sustainable architecture is

framed by the larger discussion ofsustainability and the pressing economic and

political issues of our world. In the broad context, sustainable architecture seeks tominimize the negative environmental impact of buildings by enhancing efficiency

and moderation in the use of materials, energy, and development space. Most

simply, the idea of sustainability, or ecological design, is to ensure that our actions

and decisions today do not inhibit the opportunities of future generations. This term

can be used to describe an energy and ecologically conscious approach to the

design of the built environment.

Sustainable building materials

1.BRICKSHistory

The use of bricks in the Modern period stems from a revival of brick making in the late 13th early 14th centuries inresponse to a combination of a shortage of local stone and the influence of Europe where brick was used extensively.

By the middle of the 16th century, brick making had become a distinct industry competing with stone as a structural

material.

As the industry grew, bricks became cheaper leading to its travelling downwards through the social spectrum. With

the introduction of the railways in the 19th century, significant consignments of brick could for the first time be

transported from the brickfields, such as those in Bedfordshire, to the conurbations of London, the Midlands and the

industrial North where they were used to build terraces for housing a rapidly expanding working class.

In the 20th century, mechanisation largely replaced making bricks by hand and this with other innovations helped fuel

the building booms of the inter-war years and again in the 1960s and 70s following the rise in post war population.
http://en.wikipedia.org/wiki/Sustainabilityhttp://en.wikipedia.org/wiki/Sustainability


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Brick is a traditional building material. Heed is still paid to its almost unique quality of conveying a genius locii upon

any building built from local clay. Brick construction itself continues to be regarded and taught as one of the

fundamental construction types of contemporary building, and the industry itself continues to flourish.

If the last few decades have brought opportunities through technological development, so too have they brought anew scrutiny in which fired clay bricks are examined against their environmental impact. Within the current debate

concerning sustainable materials, brick is lined-up against a range of traditional and new materials. The brick industry

will be hoping to match its strong credentials of durability with tradition against alternative forms of construction

offering, particularly, reduced embodied energy.

Types of brick

Reclaimed bricks

With an estimated 2.5bn bricks1 resulting from demolition each year, it is not surprising that there is a healthy market

in reclaimed bricks. More of a surprise might be in the knowledge that only 5% of the 2.5bn are actually reclaimed

50% are crushed and used in hardcore and fill.

The Demolition Protocol states that bricks have a recovery potential of 10% - rising to 100% in some buildings.

But what restricts the current recovery of usable bricks is complicated, though two factors are salient: the


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The manufacturing process can be loosely divided into 4 stages.

Extraction (or Clay Winning)Clay is removed from quarries and transported to the factory (though traditionally factories were usually adjacent to

the quarries). Once it has reached the factory the clay is ground down using rollers into fine powder before being

mixed with water.

FormingBricks can be formed by one of two basic processes:

Extrusion Clay is forced through an extruder and out through a die into a continuous brick-shaped column. The

column is cut into single bricks ready for the dryers. Extruded bricks are generally perforated but cannot be frogged.

Soft mud moulding Clay is thrown into a mould which has been pre-lined with a releasing agent such as sand, oil

or water. The excess clay is removed from the top and the brick released from the mould. Prior to mechanisation, this

was all undertaken by hand but the labour-intensive nature of the process and its consequential expense means

that in modern time hand made bricks tend to be reserved for niche applications and specials.

DryingTo prevent moisture from causing bricks to explode in the kilns, they are first dried before being fired. Drying takes

place in conditions of between 80-120C, lasts for between 18 40 hours and can cause shrinkage of up to 10% on

each dimension.

FiringThe dried clay is fired to fuse clay particles and impurities (vitrification) to produce the hard brick in its completed

form and livery. Bricks can be fired in either small batches in Intermittant kilns or the more energy efficient and

larger capacity Continuous kilns. On completion of firing the bricks are selected and packaged a process that can

be either manual or automated.

Reusable if used with lime mortar


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Downcyclable into low-grade fill / aggregate

Durable

Large reserves

Un-reclaimable if used with Portland cement mortar

High embodied energy

High output of CO2

The firing of bricks can produce a bag of pollutants including fluorides, chlorides and oxides of nitrogen andsulphur. Strict limits are placed on emissions in the UK.

Clay extraction has a long-term environmental impact on the landscape

Transportation can add considerably to the embodied energy

Thermal conductivity2

- Density 1200 kgm3: 0.36 W/mK (Protected); 0.36 W/mK (Unprotected);



Embodied energy

- General bricks: 3 (+/-1) MJ / kg (3) or 2.67 MJ / kg (excluding transport to site) (7)

- Facing bricks: 8.2 MJ / kg (very small sample size)(3)

Calcium Silicate bricks

Despite the method of using steam under pressure to cure sand and lime being patented in England in 1886, much of

the subsequent development and eventual use of calcium silicate bricks has prospered more in Europe than the UK.

Notable uses of the brick in London include Battersea Power Station and the RIBA building in Portland Place.

Calcium silicate (sandlime or flintlime) bricks are made by mixing quicklime or hydrated lime with silica sand

together with enough water to allow the mixture to be moulded. The mixture is left until the lime is completely

hydrated when it is pressed into moulds and cured in a high-pressure autoclave for two to three hours. In this process

the lime reacts with silica to form hydrated calcium silicates, producing a durable strong brick. The finished bricks are

very accurate and uniform, although the sharp arrises need careful handling to avoid damage to brick.


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Through use of less energy and without the air pollutants associated with firing clay, calcium silicate bricks are

considered to render significantly less impact on the environment than clay bricks.

Reusable if used with lime mortar

Old bricks can be crushed and recycled into new bricks without loss of quality

Durable

Large reserves

Extraction of sand can cause landscape degradation


Thermal conductivity2:



- Density 2200 kgm3: 1.51 W/mK (Protected); 2.06 W/mK (Unprotected)

Embodied energy3:

8.2 MJ / kg

Unfired Clay bricks (generally non-load bearing)

Unfired clay is one of civilisations oldest form of building material with origins located as far back as 14000 BC

around the Lower Nile.

Following in the wake of the widespread use of unfired clay in, particularly, Germany, UK architects are increasingly

attracted to the use of unfired clay in construction because of its perceived benefits to indoor air quality as well as its

very low environmental impact.


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Commercially available unfired clay bricks are commonly made of an extruded mixture of clay, sand and water with

sawdust added as a binder, which is then air-dried.

Reusable and recyclable

Very low embodied energy

Very low waste

Large reserves

No emissions during manufacture

Can help to regulate humidity

Generally non load-bearing

Will degrade with prolonged exposure to water


Can place restrictions on internal decoration

NOTE: WE MUST PUT ONLY MAN POINT ON POWERPOINT

2.RAMMED EARTH

Rammed Earth

Rammed earth walls (aka pise) are constructed by the compacting (ramming) of moistened subsoil into place

between temporary formwork panels. When dried, the result is a dense, hard monolithic wall.

Rammed earth is an ancient form of construction, usually associated with arid areas. There remain plentiful

examples of the form around the world evidence that rammed earth is a successful and durable way of building. A

few historical rammed earth buildings are to be found in the UK.

In recent years, rammed earth has become popular amongst environmentally-conscious architects as well as those

seeking an element of exoticism. Contemporary examples include:

- The Eden Project visitors centre in Cornwall

- The AtEIC building at CAT in Powys

- The Genesis Project in Somerset

- Rivergreen Centre at Aykley Heads in Durham- Pines Calyx conference centre

Though there is a growing number of buildings including rammed earth in the UK, its prospects of entering

mainstream construction as a structural material are limited due to formwork and labour costs involved together with

a climate that has relatively high humidity and moderate external temperatures.

The likely future for the application of rammed earth is as:
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- Thermal mass.

- Internal load-bearing unstabilised walls.

- External load-bearing stabilised walls.

Distinct appearance

Natural and readily available

Low embodied energy (a level similar to brick veneer construction)

Unstablised earth is reuseable post-demolition

High moisture mass, hygroscopic - helps regulate humidity

Use of local soils supports sustainability practices.

High thermal mass (though work is still underway to quantify its extent)

Airtight construction achievable

Traditional form of construction

Modern methods are widely tried and tested overseas eg Australia

Concerns over durability requires careful detailing

Poor thermal resistance external walls require additional insulation

Not all soil types are appropriate

High levels of construction quality control are required

Longer than average construction period

Few modern examples exist in the UK relatively untested in UK climate.

High clay content can cause moisture movement. Structures may need to accommodate this.

No UK codes of practice

Adding cement stabilisation can compromise environmental credentials


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Rammed Earth (RE) and Stabilised Rammed Earth (SRE)

Many of the shortcomings associated with the durability of rammed earth (primarily external surface protection, water

resistance, shrinkage and strength) can be averted by the addition of a stabiliser. This has become general practice

in Australia where it perceived to reduce uncertainty and risk. Though other forms have been used, the most common

stabiliser is cement, which when added typically makes up between 6 or 7% (by volume) of the mix.

The addition of cement (high embodied energy), however, is seen by many to compromise the environmental

credentials of rammed earth though this might be balanced out when additional protection and maintenance of non-

stabilised rammed earth is built into the equation.

Building Regulations

For walls constructed from stabilised rammed earth (SRE):

Part A Structure Rammed earth has proved to be suitable for loadbearing and non-loadbearing construction.

Compressive strength is a maximum of 1MPa for unstabilised rammed earth and approximately 10MPa for

stabilised rammed earth.

Part B Fire Safety Rammed earth can be classed as non-combustible material (Table A6).

A 300mm wall is capable of providing fire resistance of at least 90 minutes.

Part C Resistance of moisture Rising damp is prevented by DPCs.

Penetrating moisture is limited through absorption and subsequent evaporation.

Weather erosion is reduced / prevented through appropriate detailing eg extended eaves, raised plinths,

rainscreens etc.

Part E Resistance to the passage of sound Rammed earth walls provide effective acoustic separation

Where floors are supported by separating (party) rammed earth walls, design detailing should follow the norm for

other solid masonry walls, but with the additional requirement to accommodate moisture movement.

Part L Conservation of fuel and power


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U-value of 300mm rammed earth wall "H 1.5 3 W/m2K, therefore insulation needs adding in external wall

applications.

Regulation 7 Materials and Workmanship

Fitness of rammed earth materials determined by sampling, lab testing of materials or precedence. (see belowSREregcompliance.pdf)

Adequacy of quality is measured against provision of the specification, test panels and previous works.

For more information on Building Regs compliance, refer to 'Stabilised Rammed Earth - Physical Properties and

Compliance with UK Building Regulations' published by Chesterfield Borough Council. The main source of reference

is Hall & Djerbib's 2004 study 'Rammed Earth Sample Production: Context, Recommendations and Consistency'.

Design issues

1 Insulation

There are few examples of rammed earth walls combining insulation in the UK. Most contemporary walls remain

un-clad. The following suggested solutions have yet to be thoroughly tested.

Because of rammed earths poor thermal performance, extra insulation will be required.

Rammed earth is hygroscopic. Wherever walls are clad externally, cladding systems and finishes must be vapour-

permeable to allow evaporation. This is important for unstabilised walls, but less-so for stabilised walls where the

stabilising agent will impair breathing. Non-the-less, it might be wise to consider vapour permeable solutions for both

instances to reduce the chance of condensation build-up on the inside face of insulation.

Vapour permeability is less of a concern when specifiying internally applied insulation - when moisture is

encouraged to evaporate externally. Internally, insulation specification is a lot more flexible, though its application

directly to the face of the wall should be avoided.

The strategic decision to be made is where to locate it - inside or outside - both have advantages and disadvantages:

External insulation

Wall is protected from weathering


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Exposed thermal mass internally

Loss of characteristic appearance externally

Insulating render

Materials: hempLime, proprietary renders, mineral-based renders and hygroscopic insulation (see also: Insulation

materials compared)

Insulation board and render

Insulation materials: breathing insulation: cellulose slab, composite wood wool board (not cement-based), wood fibre

board, cork, hemp, hemp-lime . (see also: Insulation products and Insulation materials compared)

Render: limecrete, mineral render, glaster, proprietary permeable renders

Rainscreen cladding


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Insulation materials: breathing insulation: cellulose slab, composite wood wool board (not cement-based), wood

fibre board, cork, sheep's wool, hemp, hemp-lime (see also: Insulation products and Insulation materials

compared)

Cladding: wood, tiles, slate, board and polymer-based render, proprietary cladding systems

Internal insulation

External appearance maintained

Loss of available thermal mass

Free-standing studwork with infill insulation

asdf

Insulation materials: Cellular glass, Mineral wool slab, Expanded polystyrene, Phenolic foarm, Polyisocyanurate

(PIR), Polyurethane (PUR). (see also: Insulation products and Insulation materials compared)


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2 Weather protection All water should drained away from the walls

Walls should be constructed upon raised footings

Avoid sites that are liable to flood

Protect the wall where possible from rain using adjoining elements such as projecting roofs

Allow excess moisture means to evaporate from walls

On exposed sites, consider rainscreen cladding or render

Water sealant protective coatings are not recommended

Protection given by the roof

The eaves provide protection from rain. An emerging rule-of-thumb states that the overhang should be equivalent to

a third of the overall wall height. (source: Peter Walker)

Footings and base


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The DPC should be finished flush with the wall suface to avoid splash.

Blue engineering brick might be considered as an alteranative to the DPC membrane.

A filter drain will also reduce the height of splash by means of radom splash effect.

As with all solid walls, ensure careful detailing to avoid cold-bridging.

Cork

Cork material is harvested from the cork oak (querbus?) tree, but instead of needing tocut down the tree to source the benefit of the raw material, the bark (or outer skin) of thetree is peeled off, and the tree is left to regenerate. Cork, as a raw material, is mainlysmall microscopic pockets of air encapsulated by the cork fiber lignin. This cellularstructure gives cork products tremendous thermal and acoustic properties, as the air isacts as insulation.


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The floor joists and structural beams and headers in this house are made fromTrusJoist engineered lumber. This manufactured wood product is made of fibers fromsecond- and third-growth timber and from nontraditional tree species such as aspen andpoplar. The adhesive used to bind the wood fibers together is MDI (methyl diisocyanate)polyurethane. It contains no formaldehyde, so there should be no off-gassing after

installation. It is highly toxic during the manufacturing process, however, so specialpollution-control and health safeguards are required. For worker safety, the pressingprocess used to shape the wood product is remotely controlled, and the manufacturingplants meet strinThere's no need to use whole trees, large trees, or old trees to produceengineered lumber products, so those resources can be conserved. In fact, engineeredlumber is made with about half the wood fiber of solid-sawn wood. And becauseengineered wood is so strong, it's not necessary for a builder to combine multiple,standard-size lengths to create a beam that stretches across a tall wall, a wide ceiling,or the floor of a huge room. Instead, the builder can order a board cut to a preciselengtheven if it's very longwhich means less cutting on site and less waste headingto landfills.

And, manufacturers like to point out, engineered wood, while a composite of differentkinds of wood fibers, still starts as trees, which are renewable and remove carbondioxide from the atmosphere.

Some manufacturers are taking the additional step of incorporating wood fromsustainably managed forests that are certified by programs such as the ForestStewardship Council, the Sustainable Forestry Initiative, the Canadian StandardsAssociation, and the American Tree Farm System. Manufacturers of engineered woodcan earn certifications at different levels if they buy a substantial portion of their woodfrom sustainable forests and keep tabs on the chain of custody of the product

gent environmental standards.

Medium-Density Fiberboard (MDF)One of the concerns associated with particleboard and fiberboard in the past has beenurea formaldehyde offgassing. A new generation of board is now available that is madewith phenolic resins that do not offgas formaldehyde, yet are stronger than theirpredecessors. Agricultural fiberboards often use MDI binders, which do not containformaldehyde, and may be preferable for indoor air quality.

FlooringBamboo was used for the flooring in the main rooms of the house. Bamboo is a rapidlyrenewable resource. Unlike hardwood trees that require 40 or more years to mature,bamboo is a grass that matures in less than six years and is harvested over and overagain from the same plant. It makes a highly durable floor covering, harder than oakand more dimensionally stable than maple.
http://www.trusjoist.com/EngSite/http://www.trusjoist.com/EngSite/http://www.trusjoist.com/EngSite/http://www.trusjoist.com/EngSite/


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BambooQuick Fact: Bamboo is not wood, but rather a type of agrass. As it can grow up to 12" a day, it is veryenvironmentally friendly and quickly renewable. In fact, itcan be harvested in as little as 5 years. Bamboo is very

strong and stable, more so than many hardwoods. Yet it isless likely to swell or shrink. It is easy to install, reasonablypriced, and the finished product holds a beautiful grain.

1.2. The Palmyra House is a vacation home in the south of Mumbai that resonates

not just for its clean modern look but also for its rich selection of local sustainable

materials. Situated on the coast of the Indian Ocean, this handcrafted home wassensitively placed in a coconut grove and much of its structure is made from thematerials harvested on site or nearby. The Palmyra House was recently honoredas one of 19 shortlisted entries in the 2010 Aga Khan Awards for Architecture read on to learn how modernism and materials meet to create this enlightenedretreat.
http://inhabitat.com/materials/http://inhabitat.com/materials/http://inhabitat.com/2008/09/05/palmyra-house-by-studio-mumbai/http://www.akdn.org/akaa/default.asphttp://inhabitat.com/2010/05/28/stunning-palmya-house-showcases-local-sustainable-materials/05_palmyra_house/http://inhabitat.com/materials/http://inhabitat.com/materials/http://inhabitat.com/2008/09/05/palmyra-house-by-studio-mumbai/http://www.akdn.org/akaa/default.asp


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3.4. According to Studio Mumbai Architects the superstructure is made

from ain wood, a local hardwood, and was constructed using traditionalinterlocking joinery. They then wrapped the buildings with handmadelouvers made ofpalmyra palm trunk also a hardy and local tree. The stonefoundation, as well as the sand for the plaster was also locally-sourced. Throughthe amalgamation of appropriate materials the faade is in utter agreement withits surroundings.

5. With help from the palms overhead and a ocean breeze, the home uses the

ancient technique of having an open skin to shed latent heat. An aqueductweaves though the grounds and ends at a pool between the two offsetstructures. The interior is austere and refined to provide a calming sense oforder.
http://studiomumbaiarchitects.blogspot.com/2007/12/palmyra-house.htmlhttp://inhabitat.com/?attachment_id=120984http://inhabitat.com/?attachment_id=120984http://inhabitat.com/2010/05/28/stunning-palmya-house-showcases-local-sustainable-materials/08_palmyra_house/http://studiomumbaiarchitects.blogspot.com/2007/12/palmyra-house.htmlhttp://inhabitat.com/?attachment_id=120984http://inhabitat.com/?attachment_id=120984


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Materiaux Final