Building Knowledge:

Paul ReynoldsAdvisors:Robert J. Koester + Donna Sink

A Systems Approach to Framed Straw Bale Construction

Building Knowledge:

College of Architecture and PlanningBall State UniversityMay 2012 M.Arch Candidate

Author:Paul ReynoldsAdvisors:Robert J. Koester + Donna Sink

A Systems Approach to Framed Straw Bale Construction

1

Table of Contents

247

3144474854 56 6468 7072

AbstractIntroductionProjectBuiltReflectionAppendix Precedent Studies Project Siting Interview Book Reviews Definitions Image Credit References

2

People are makers. We are given this instinct from birth and we gather knowledge as we grow. One of the steps in life to gather knowledge can be formal education; as I have chosen with my pursuit of an architectural education. From my experiences in the architecture curriculum, I have gained a working knowledge of construction principles and building methods. This thesis looks at combing the knowledge of conventional Western platform framing and the Nebraska-style of straw bale construction, wherein bales are used like bricks. The project began by looking at different details of the framed straw bale method that would be found in a typical house. The details include: wall types, floor types, foundation types, openings, and roof types. A multitude of techniques are cataloged in this book while a few of the techniques were investigated, in detail, through a physical construct. This project investigated straw bale as a building material for several reasons. Straw is a by-product of our food production process. Straw bale construction can be a relatively low-skill building process. Straw bale also has an appealing aesthetic. The straw bales were not to be load-bearing, the project was to be physically constructed at full scale, and the project was critiqued during design development, full-scale construction and upon completion. This project shows the construction of a prototype of many different detail conditions of differing materials joined together. The results of this project included not only digital and physical prototypes, but also careful attention to budget/cost and materials. The project allowed me to acquire skills which will be useful in my career pursuits.

Abstract

02 03

3

abstract

04

4

My interest in building began long ago. As a child I would spend countless hours constructing little “towns” in the dirt around which I would play with my toy cars. As I grew up, I moved onto bigger things: LEGOS. I would build small towns and neighborhoods out of these. As I aged, my interest in how things worked grew and I became vested in computers, cars, and now buildings. I am fascinated by how they go together and I have a desire to build them. I began architecture school with the dream of becoming an architect - with no idea what that really meant; I just knew that I would be able to design buildings. I now know that becoming an architect does not necessarily limit my ability to only design buildings; I’ve since learned about design-build and have grown more interested in the constructing of buildings. The growing interest in building has led me to look back and reflect on my education and critique it. After my first year in the College of Architecture and Planning at Ball State, I declared my major as architecture. This kick started my learning of buildings. I was met with an Environmental Systems course taught by Walter Grondzik and a Building Technology course, taught by Tim Gray. These courses were a great introduction to how buildings work. At the same time I was learning this material, I also was enrolled in a studio course. At the time, I believed studio to be the most enjoyable course, as I had free reign to design. The next few years, more Systems and Building Tech courses followed along with more studio courses. I am now finding that those electives (Systems and Build Tech) were more valuable than I could have anticipated. The studio courses were meant for the students to employ the technical knowledge we were gaining and combine it with our artistic design abilities. I look back on these studios and can only think that these projects were completely theoretical and rarely did we follow up on implementation details. My final semester of undergrad, I finally got a chance to do some design-build work. We partnered with another university and as a result of the studio, I learned to weld and built a piece to be used in a theater performance. After four years of architectural education, I felt as though I could not detail a building. Rather, I was confident in my ability to make semi-realistic renderings. Along came graduate school, which gave promise to learning more about the how a building goes together. My first semester did not yield quite as much of this knowledge as I was hoping to get. My professional practices course proved to be the gold mine of information regarding how firms worked (or didn’t work). This was followed by a summer session in a design-build studio and an elective where we were to create installations. The design-build course was great in terms of widening my perspective on building. The project involved client interaction at every step, a real world budget, and also required testing of the built pieces as they would be tortured by toddlers and young children. Entering into the final year of the graduate curriculum, we were given free reign on any topic of our choosing. The ability to choose whatever I wanted left me feeling overwhelmed, especially when facing the challenge of “adding to the discourse.” I had no idea where to take it. Fortunately, I did know one thing, I wanted to build whatever I would be designing at full scale. I have chosen to look into the more technical details of building, mentioned earlier. With an interest in straw bale construction, I chose to design and build a small, generic test cell to provide the opportunity to engage many different material conditions. Not only does the project involve technical details of how materials are joined, but I also investigated the issue of having a budget, building on a site, and meeting a time line. This project essentially was a simplified version of any of the architectural studio projects I have had the

Introduction

5

chance to digitally build up to this point, with the difference being that it is physically be constructed. I decided to begin my research by exploring the traditional approaches to straw bale construction by reading books and exploring existing projects. For my field trip, I had laid out a road trip to visit straw bale structures, but sadly only one of the builders was willing to meet with me. I traveled to Goshen, Indiana to meet with Greg Lehman. He had no formal education in architecture but he had a desire to build, the same force driving me. The short-term goals of this thesis project included but were not limited to: creating a built project (outside of the digital, rendered world which we are accustomed to in the program), learning more about building details and construction technologies to enable myself to become a builder, learning more about straw bale as a construction material, learning (and experience) how to put a building together, and getting some experience in cost estimating and working with a budget. Before explaining more about the project and some of the methods of research, the question of “why straw bale” needs to be answered. The first reason is the simplicity of the bale as it is essentially a block. The level of skill needed to stack blocks is relatively low. Many times, groups of friends and families will get together to construct straw bale structures, some of them never having any knowledge of building. The ability to move the bales physically and create a structure is empowering. The second reason is the performative aspects of straw bale. Straw bales are good at supporting loads, restricting heat transfer, and absorbing sound. These

intro

05 06

6

properties alone make bales of straw an attractive solution to building, not to mention the fact that straw is a natural by-product of food production. As long as the methods for producing food such as wheat, oats, barley, rye, and rice continue, the ability to acquire straw will remain. Given these two points about straw bale, I find that it is an attractive construction technology. To begin the project, a generic test “cell” was designed with different materials and conditions. The idea of creating a generic model enabled this knowledge to be scaled with the project size (i.e. from a shed, to a house, to an office building). To maximize the opportunities I started in the computer and tried to reconfigure the cell with different conditions. The end result is a physical construction that displays some of the conditions created digitally, with the rest of the conditions displayed in diagram and digital formats. The beginning portion of the project included gathering information and knowledge on some of the techniques used in traditional straw bale construction.

7

project

Thisportionofthebookdocumentsthethesisideainaprojectform.Inmyopinion,thedefinitionofprojectinthisinstanceis a physical and digital exploration of a construction system that is documented and diagrammed fully. The project began with the construction system. The system was detailed to explain options for assembly and deployment. The bulk of the explanation is in diagram format which is followed by the actual construction. This section begins by showing the diagrams with their accompanying text. Following the diagrams, there is a short piece on the digitally-designed construction system.

Project

Simple framed bayBay consists of two side rails, a toe-up to raise the bales, and a cross brace.

8

project

Assembly of bayThe joinery of the bay uses half lap joints that are bolted together. The side rails are made individually and then brought together with the rest of the components.

9

Joining multiple baysThe joining of bays can be done in several different ways. Although there are only four shown here, there are more possibilities for joining bays.

Thefirstmethodisin-linejoining.Tojoinmultiplebays,twoseparatebaysandarebroughttogether.Theyarespace by the toe-ups and the cross bracing.

10

project

The next method shows a corner detail with two bays joining into a corner box. The corner box will hold bales that are turned vertically.

11

The next option of joining shows a bay intersecting another bay on its long side. This requires inserting cross members to tie the dividing bay into the intersected bay.

12

project

Thefinaloptionshownisamethodthatallowslighttocomeinfromthecorner.Thetwobaysarejoinedbysiderail braces that extend beyond the rail.

13

The bay allows for many different treatments as it is the structure that allows multiple attachments to it.

built-in seat light shelf light portal

Flexibility of the bay

14

project

full-bay light portal partial bay light portal

15

Levels of DeploymentTheconstructionsystemisnotconfinedtoopaquewalls.Thesystemcanalsobeintegratedintoaroof,afoundation, or also different types of openings.

Roof DeploymentShownherearedifferentwaysinwhichthesystemcanbecomearoofstructure.Shownare:aflatroofwithoutan overhang, a shed roof without an overhang, a gable roof without an overhang, and a gable roof with an overhang.

16

cable

project

17

cable

18

cable

project

19

cable

Filling the baysThebayissizedsothatfillingthebayisassimpleastossingthebalesintotheframe.

20

project

21

Although there are several types of openings that can be created, the placement of the apertures is also critical. Shown here are some different ways in which the apertures can be positioned. They are labeled by having views (V) or no views (NV).

High slit opening (NV)(NV) Low slit opening (V )Medium viewing opening

Placement of Apertures

(V )Middle slit opening (V )Between bay(V )Large viewing opening

22

project

23

Utilities

above ceiling

Utilities + Structure

Due to the nature of the wall cavity and the depth of the beams created in this system, the utilities can be placed above or below the space. The depth of the wall system also allows for bays to be left as mechanical chases.

Because of the truss type construction, a tension member must be added, in this case it is a cable. The cable is attached to closed eye blots and tightened by turnbuckles. The eye bolts take place of the usual hex bolts that are found in the joints.

Wood sheetingExposed (no skin)

Rain screenCorrugated metal

Exposed (covered)Vertical siding

Skinning the baysBecause the framed straw bale system resembles a more traditional framing system, the possibilities for skinning the structure are not any less. There remains the possibility for a common skins as well as traditional straw bale skins. This system allows for almost any possibility.

24

project

Gypsum boardPlastered

Corrugated acrylic

Horizontal siding

25

To investigate the construction system more fully, the framed straw bale system was used for the design of a small home. For this particular instance, I chose several different types of openings but only one skinning method. The house is roughly 1,000 square feet and has two bedrooms and a full bath as well as a half bath. The concept for the space planning of the house was drawn from Rudolph Schindler. As you enter the home, there is a two-story public space. This space combines the kitchen, dining, and living room. The private spaces are raised up onto the second level and the servant spaces are pushed under the private space. Pictured below is a diagram showing the shape of the building came to be. Shown on therightarethelower(top)andupper(bottom)floorplans.

Although these numbers could suggest more homes be built using straw bale construction, they do not imply that straw bale is the best construction system for every climate or building situation. For example, climates with high relative humidity tend to saturate the bales with moisture. Bales that are not allowed to dry out will grow mold. Some consideration at the front end of a projectcouldhelpdeterminewhetherthisisthebestfitforaproject.

Food for thought:Average home size in the US in 2010Average amount of wheat harvest land*Yield per acre of farm landTotal number of bales possibleNumber of 3-string bales for a 1000 sq. ft. home*Estimated number of bales for an average US homeAcreage needed to supply bales for a homeNumber of average size homes possible with straw baleNumber of NEW homes built in the US in 2010*

2,392 square feet53 million acres75-100 bales4 to 5 billion bales625 bales1500 bales15-20 acres2.6 million homes583,900 homes

26

project

living

up

open

dn

bath

bedclo

bedreading

dining

kitchenstorage

bath

laundry mech

27

28

project

29

30

07

built

This section of the thesis book is an extension to the project section but is focused more on the actual physical construction oftheproject. Attheoutset,theprojectwasexploreddigitallytoallowquick,flexiblemanipulationof ideas.Thentheprojectfocused on building the construction system at full scale to fully understand the materials and how they come together. It began in the material yard at Solid State LLC, located in Muncie, IN. The materials at Solid State come from deconstructed homes and other buildings in the area. The material was not only cheaper than buying new lumber but also buying and reusing this material was more sustainable. OncethematerialwasdeliveredtoBallStateUniversity,Iwasabletobringitintothewoodshopandbeginwork.Thefirsttask was rabbiting and dadoing out the notches in the 2x4’s for the half lap joints. Originally I began this using a handsaw, moving uptoacircularsawandeventuallyusingtheradialarmsawforthecuts.ThesejointsareresultofthefirstpassIhadonthebay.Forthefirstbay,Itoenailedallofthelumbertogether;notonlydidthisprovetobeveryunstable,butalsoitwasnotverypleasingaesthetically. I deconstructed this bay and used the material to create the second version. The images shown here are (far left) Solid State’smaterialyard,(lowerleft)rabbitingusingacircularsawandchisel,andthefinishedjointscutbythecircularsawbeforebeingdrilled and secured together by bolts.

Built

31

08 09

32

10

11 12

built

To estimate the amount of material that I would be using, I used a digital version of the proposed structure. I cut to length and rabbited the joints out and moved the operation outside where I began constructing. Armed with a drilled, a ratchet, and a wrench, I drilled the holes for the bolts and bolts the members together. The images shown are (far lower left) adding the cross members to the side rails, (far top) the side rails and trusses put together, (far lower right) detailed image of each joint and its two bolts. The lower left image shows the side rails attached to the truss, creating what would become two walls and a roof. The lower right image shows the two rail and truss sections attached together, spaced using the toe-ups, with the cross braces. Thisstepandthepreviousstepwereeasilycompletedworkingalone.Ibenefitedatthesestagesbypreplanningthetasksand also being assisted by the digital model. Due to the sizes of the module, the components were easy for one person to transport. In hindsight, I should have leveled the southern portion (right side of the lower images) of the assembly as it only complicated things later in the building process. In a full-building application, I imagine that the trusses and side rails can be assembled/attached separately then joined together once the walls are in place on site. A structure could quickly be deployed in this manner before beingfilledwiththestrawbales.

33

13 14

34

15

built

Thiswasoneofthemorelabor-intensivestepsinthebuildingprocess;fillingtheframewiththestrawbales.Thebaleswerestored on the CERES patio. At the request of the facility manager, the bales were not moved through the building, but tossed down over the wall. I brought the majority of the bales to my project “site” in the same morning (shown in the lower left image). Because I measuredthebalesaheadoftime,thebaysizeisbaseduponthesizingofthebales,thebalesfitrightintotheframewithoutmucheffort. One of the advantages of using bales is that they area also able to be stacked and used as stairs, which allows installation of theupperbaleseasily.Thelowerrightimageshowshowthebalesfitintothebay.Thebaleswerestackedwiththebaleslaidflat.Thefarleftimageshowsthefirstpassatfillingthebaywithstrawbales.Thecloserwallinthisviewhasanaperturethathasbeenframedout,allowingforapplicationofawindow.Atthis“firstpass”atbuildingtheframeiscomplete.Afewtweaksweremadeata later time and they will be described later in this book. Now the straw must be covered with a skin. While the bales were being stored, they were covered with a tarp to keep them dry. Because tarping this built piece would hide the project, skinning the frames makes more sense, and it also gives me the opportunity to experiment with skinning the bays using a method outlined previously in the diagrams. Next step, creating a skin to cover the bays.

35

16 17

Along with the large amount of dimensional lumber that I purchased from Solid State, I also purchased some 1x boards. They varied in size from 9 inches up to 13 inches wide. I used these to create ship-lap siding. To do this, I had to get the boards all the same size. The process was fairly simple, as it included cutting the boards to length, joining the edge then cutting to width on the table saw. Once I had all of the boards to the same size (shown in the lower left), it was time to rabbit the edge. I wanted to create aquarterinchrevealbetweeneachoftheboards.Thefinishedboardsareshowninthelowerrightimage.Inordertocreatethisreveal, I made the top tab of the joint deeper. This deeper joint held the top board up (shown in the far upper left image). For the sake of time and money, I chose to skin two sides of the structure, beginning with the front face (shown in the far lower left image). I also wanted to show how the siding would be attached around an aperture (shown in far right image). The siding was attached on the top lap, which is covered by the overlapping board above it, and also along the furring strips. At this point, the built project was considered “complete” and I shifted gears to start documenting the built piece as well as producing digital diagrams (shown in theprevioussection).Theremainderofthissectionwillconsistofimagesofthefinalpieceaswellassomeofthedetails.

36

18 19

built

37

20

21 22

38

23

24 25

built

39

026

27

28

40

29

30 31

built

41

32 33

42

34

built

43

35 36

Reflection This section of the book is a collection of some of the thoughts I have after completing my project, including things I learned from this exploration and where the project could lead me in the future. At this moment, I don’t feel that I am able to give a list of more conceptual things learned but I feel to fully complete this project, the reflection must not be single instance, rather a gradually reflection over time. Insights: - Freeing myself from the precision of the computer allowed me to engage the material in a real way. - Toe nailing lumber together isn’t the greatest solution, nor does it look great. - The bales may have a common size but no two bales are the same. Be ready to use some force if the bay isn’t correctly sized. - The first idea isn’t always the best, nor even is the final idea. This project has evolved a lot from the beginning. - Straw is much messier than I had anticipated. It requires constant attention as the loose straw is much more dangerous than the bales. - Talk to people! A lone individual can’t think of everything. (and I don’t know everything) - Even at a small scale, sequencing a built project is difficult, especially when facing external factors. - Old wood has interesting characteristics that make it fun, yet difficult to work with. I don’t believe any of the pieces of wood that I had were the same size dimensionally. Using today’s dimensional lumber would make this sort of investigation much smoother as pieces are all virtually identical. - Working solo is quite difficult and a second set of hands (or more) would help things move along much smoother. - This method of joinery is quite time intensive, the very thing I intended to keep away from. Further investigation of this system would begin by revisiting the method of joining components. - Errors become compounded when not addressed early (particularly the levelness of the ground surface). - I anticipated the tasks to take a certain amount of time but they often took much more. Partly this was due to external factors (availability of equipment), but also the time taken to move back and forth between the site and the wood shop. For example, draining multiple batteries on hand tools in a day starts to eat into the daylight.

There are still a few bigger issues that remain unaddressed thus far and they follow: The side rails that make up the bay resemble ladders and as a result the space between the “rungs” is an empty space. If the bay is sized in a way that the bales are squeezed slightly by the rails, the ends will protrude into this empty space but some extra attention will be required in these areas. I suggest that a light mixture of some clay and straw be added in this area. Because it is the looseness of the straw that creates such a wonderful insulation, I recommend that the clay portion be as small as possible and use as much of the loose straw as possible. The reason for using more loose straw is to keep from creating thermal bridges. A method that is possible but I do NOT suggest is using EPS rigid insulation cut to size for these gaps. I do not suggest it as one of the benefits of straw bale insulation is the lack of toxicity of straw. If straw bales burn, they do not release the harmful toxins that are found in EPS rigid

44

45

reflection

insulation. These gaps in the ladders may have yet another possibility for filling the space. Wiring a structure that has been built using this construction system can be done in a couple different ways. Everything could be placed in the floor or in the ceiling but the gaps in the side rails also could become channels which wiring could be run through. It would be easy enough to fabricate a chase that is attached to the bays but does not interfere with the bales or their insulative properties. The bolted connections in this assembly potentially create assembly issues. If the bolt is protruding into the bale, there is no issue, but where the issues lie are when a material must be attached directly to the surface of the frame. There are a few different solutions. The first solution is to countersink the bolts . The next solution is to use sleeved screws. These screws have a considerably lower profile, but they still may need countersunk as well. Another solution to this is to create a pocket in which the bolt will set. The best approach generally is to create a flush surface to ensure no problems. The cladding method that I have shown in the built section is that similar to a rain screen. There are a few key points to be said about it. The first being that straw bale MUST breathe. In the event that straw bales get wet, they need to be able to respire. If a vapor barrier is located on either side of a bale, it will not allow the bale to reject the moisture. What can be done? An air barrier is certainly acceptable but typically this is created by plastering the bales. Another key point to be made here is that the skin on either side of the bale needs to be vapor permeable, but the skin on the interior side should be less permeable than the outer skin to encourage moisture to wick its way out of a building rather than back into the building. In the event that a rain screen is used, a water barrier should be placed directly on the wall-facing side of the skin. This will allow the moisture escaping the bales to condense on this surface, then draining down the skin and exit the assembly. The idea of community. Typically in straw bale construction, “barn raising” events are arranged where communities, friends, and/or family will come together as a group to stack bales or plaster the bales. I would like to think that this system can allow all of that to happen. From the assembly of the bays, filling them with bales, to skinning the bays, I believe that these can all be community activities. The great thing about straw bale, is that the level of skill needed to assemble isn’t high. Stacking bales is a relatively low-skill task. The way I imagine this process taking place would be: the frames are built in a factory where weather isn’t an issue and for quick assembly; these pre-assembled components are then brought to site; the group meets to do a “bay raising” and begin filling them with bales. With simpler building layouts, this “bay raising” and “bay filling” could be done in a weekend. A third day could involve the skinning of the structure. All of this can be done as a group. If the facility were available, some of the group members could even participate in the fabrication of the rails and other components. I don’t seek to take the community aspect out of straw bale construction, but rather modify the process and system of construction. How does this help me in my future pursuits? I believe that managing a project from idea to built form is a very valuable exercise. This exercise enabled me to get a hands-on experience with real materials rather than drawing absolute line work in the computer. With my interests in design-build, I believe this is directly relevant to my search for work opportunities.

46

How can I continue with this project? I could begin to test some of the apertures outlined previously and see how they perform in terms of daylighting. A comparison of this system with not only a stud framed house, but also a Nebraska-style straw bale house would be crutial. The comparison should be in terms of cost per square foot and estimated build time. Another way to explore this system further is to investigate solutions that aren’t completely orthogonal. Creating a system with angled straw bale walls could be quite compelling. Yet another direction to explore further would be the connections and joinery of the system. As mentioned previously, the joining in this solution defeated part of the initial purpose of the study, to cut down on the construction time with staw bale construction. Taking this one step further, how might other joints occur. I have shown several in diagram form but these aren’t the only methods of joining walls are they?

appendixAppendix

Precedent StudiesProject SitingInterviewBook ReviewsDefinitionsImage CreditReferences

This section of the book is a collection of much of the work done in the Fall semester. It is the supporting content upon which my thesis and project were based. The following are found in this portion of the book:

47

48

Precedent StudiesBSU Straw bale Eco Center, Muncie, IN This project showcases straw bale as a construction material and a couple different ways of cladding the bales are shown. It is also a local project. The eco center is a small one room classroom that displays some of the modern technologies with regards to energy generation and ventilation. Many different detail conditions exist in this project. A truly immersive learning project. Student were not only in charge of designing, but also building the project. “The Straw Bale Eco Center is a student designed and constructed demonstration project for sustainable building practices and is the first constructed component of the Land Design Institute’s LandLab demonstration site in Muncie, Indiana. The Eco Center respects local climate conditions and resource flows and represents one of the first carbon neutral buildings in the region.” - Tim Gray

This project was built by a self builder in Northern Indiana. He had no background in building or architecture but had the dream of creating an eco-village. This is one of the two buildings which currently exist in his proposed village. The main structure of the building is timber frame with straw bale/cob in fill walls. The timbers came from trees on the site and were cut at a local saw mill. The house is a duplex, with a tenant occupying the lower level and the owner residing on the ground level and upper level. Interesting to talk with the owner and get his feedback on his own construction. He talked about things like siting, solar access, the use of cob, and also the ability to change materials on the fly.

Straw/Cob Duplex, Goshen, IN

37 38

49

appendix

An interesting project that has a wonderfully dynamic facade. Through the year, the facade is empty, then it acquires hay bales which are green. The bales dry and fade from green to yellow. As the year goes on and winter progresses, the bales are eventually plucked from the wall to be used for feed in the stables. As the bales are slowly removed, the wall is then exposed again. This project also has beautiful connections using wood and metal. The roof is raised above the walls to allow natural light to flood into the interior space.

For my final 601 student project, we were able to design our own program and I chose to create a student house on Cranbrook’s campus. The students would live with their professor for one or two semesters and learn about wood working forestry. I focused my attention on the design of the home and attached workshop. The building is comprised of timber framing, a straw bale skin, and then wrapped in a wooden-slat rain skin. In this project, I explored different ways of opening up the wall to allow light into the interior spaces. This could be seen as a trial run for my final project in the spring.

Somis Hay Barn, Somis, California 601 Studio Project

39 40

50

Residential and office building in London, UK Prefabricated single-family home in Austria The home and office building looked to mix things up and show a unique building. Founded on th principal of sustainable living, the main floor is raised up to allow the garden and chickens to inhabit the ground level. The tower, which raises a couple stories above the rest of the building, is doubling as a vertical library as well as a thermal chimney. The project uses a mix of different materials, ranging from straw bale to sand bags to gabion walls. The cladding used on the straw bale allows for it to be exposed yet protected at the same time. The architect opened the walls up in different ways allowing the southern facade of the building to let sun in while insulating most of the other faces.

This home is a prefabricated structure with a post-and-beam structure which is filled with straw bales. All of the walls and floors are made up of panels which are filled with bales and are clad with diagonal boards. The prebrication of these panels makes is simple to erect on site but one of the drawbacks to this system is the irregularity in bale sizes. The rigid structure grid mean that there needed to be extra attention paid to the bale panels. Any gaps needed to be filled to ensure that there would be no thermal bridging.

41 42

51

appendix

Single-family home in Dobersdor, Austria Low-energy house in Austria This unique home is positioned on site in reaction to an on-site limitation which kept the building from being oriented directly north-south. The layout of the structure sought to achieve maximum solar exposure on the southern face. The layout also is zoned in such a way that the spaces range from warm spaces to cooler spaces. The entire building is heated by a central stove. The exterior walls are straw bale infill walls which have diagonal boarding on the exterior side of the bales. A rain screen is installed on top of the boarding.

This home had started out as a conventional timber structure with cellulose insulation but after the owners interest in straw bale piqued, the architect made some design changes to replace the cellulose with straw bales. The columns were doubled up to account for the large thickness of straw bales. The house sought to meet passive house standards so a few things were added. A cork insulation was used between the double up columns to thermally separate the two. Earth-straw bricks were used on the interior to provide the required thermal mass. The earth-straw bricks assist in humidity and temperature control. The exterior finish, per the local planning regulations, was such that the building is not recognizable as a straw bale structure.

43 44

52

Passive house in Austria Load-bearing straw bale house in Switzerland This house, which is not quickly recognizable as a straw bale structure, is designed as a passive house. As with similar buildings, the house is oriented south to capture the sun during the winter. The house has a timber structure which is raised off of the ground by concrete strip foundation due to a nearby brook. The build was prefabricated and has received a wooden weatherboarding. The home supplements its heating needs with a heat pump which is connected to the air-conditioning.

This load-bearing home is situated in the Swiss Alps. The design uses jumbo straw bales, which are roughly four feet thick, to create three of the sides. There are few openings in the bales but the south-facing facade is completely glazed. The building set upon pylons due to the potential for large amounts of snow on the sloped site. It is not common to see jumbo bales used in residential structures but they are used. The roof is made of trussed girders and an insulation layer is created by two layers of small straw bales.

45 46

53

appendix

Arastradero Preserve gateway facility 501 Studio Project The home and office building looked to mix things up and show a unique building. Founded on the principal of sustainable living, the main floor is raised up to allow the garden and chickens to inhabit the ground level. The tower, which raises a couple stories above the rest of the building, is doubling as a vertical library as well as a thermal chimney. The project uses a mix of different materials, ranging from straw bale to sand bags to gabion walls. The cladding used on the straw bale allows for it to be exposed yet protected at the same time. The architect opened the walls up in different ways allowing the southern facade of the building to let sun in while insulating most of the other faces.

This studio project sought to create a regenerative studies facility. My approach was to use straw bale for the wall as it could be harvested from the food production on site. This project explored different ways of bringing light into the interior spaces. Some of the hallways (as shown in the image below) benefited greatly from these different methods. This one in particular peels the roof up to allow the sun to reflect off of metal panels which are hung on the wall. The project could be seen as a predecessor to my 601 studio project.

47 48

54

Project Siting The staging of the project began on the CERES patio. The 36 feet by 90 feet patio was more than enough. Once it came time to build the structure, it was apparent that this space wouldn’t be the best for the project as getting access to it wasn’t the easiest nor was transporting material to it. My next “site” was in the third floor atrium, where I made a made mess; It didn’t stay long. I decided the best place would be outside but I wanted it to be close to the building as well as have easy access so I chose a spot on the south patio of the Architecture Building, just east of the main door. This is a high traffic area, so it seemed to be great for showing everyone what is going on with my project. The overhang of the building covered most of the patio, which is ideal for the structure as I did not plan to completely skin/cover it. As for siting a real world application of this construction system, it could be located in many different areas, especially where straw can be found, but I would warn against building in humid climates. Because straw must be kept dry, climates with medium to high relative humidities are not ideal as they would keep moisture inside the bale. The image shown in the lower left, is of the CERES patio where the bales were stored for the semester. The image in the lower right is showing the mess created by the bales as I brought them indoors. Over the course of the couple weeks that the bay remained in place, straw was constantly shedding. The far right image, is the final siting of the project. Because it is outdoors, it was much easier to keep it swept up.

49 50

55

appendix

51

56

Interview The following is a questionnaire given to Matt Thomas, an Indiana farmer, who has grown and baled straw. I know him personally as he has stored straw in my mother’s barn on several occasions. Before I began reading about straw bale construction I wanted to go to the source and talk to a farmer who has worked with straw. I put together a list of questions to help me understand more about the entire process of the bale.

1. Where do you get your straw? (What plant does the waste product come from)Straw can come from several different plants, but the common is wheat straw. (I won’t go into the others unless you really want me to, they just aren’t common at all and are much harder to work with, and they are much dirtier as well. Wheat is the most common plant for multiple reasons including:The stems are smooth so it doesn’t scratch you up nearly as much as other straw types do.It is clean - the chaff, the dry protective castings of the wheat plant, has been removed.It is a nice yellow color that is appealing to the eye of the customerIt is very absorbent to water, manure, mud etc… and also adheres well to the soil surface after it has been in place long enough and had some rain on it thus helping prevent erosion on slopes, new lawns or construction sites.When compared to other straw types it is relatively light, but just as absorbent thus making it more ideal.

2. Are there any things that you have to look for when you are baling?(i.e. Too much greenery picked up with the straw - leading to too much moisture in the bales. Can rocks be picked up by the baler?)You are absolutely correct, there are things that are looked for when baling! First and foremost, the straw must be dry enough that it will not mold while in the bale. Typically you don’t bale for 1-2 hot days (85+ degrees) after any rain more than .25”. Also you want to watch out for getting too much living plant material in the baler because if it is still attached to the roots and alive it will have way too much water in it which can (if there is a large amount of it) cause the bale(s) it is in to mold. Mold isn’t really a problem for construction use, but if you are using it for bedding for animals it can cause respiratory problems, or possibly cause a fire from the progressive buildup of heat that can’t escape thus causing the bale to ignite. This has been the cause for many barn fires over the years, and should not be taken lightly. But it takes a pretty substantial amount of wet material in a bale to cause this to happen. This sounds simple and common since, but you want to avoid things like steel cables, loose wires, snakes, rabbits etc. Getting into the baler while you are going. And yes the animals really do happen… The baler can pick up rocks which for the quality of the bale isn’t really a huge deal unless you are feeding it, but if they are big enough the rocks can severely damage the baler if they happen to get into the wrong place. But rocks typically don’t get picked up.

3. When are you able to harvest straw? Can it happen more than once a year?

57

Interview appendix

52

58

In our part of the world, wheat straw can’t be harvested once a year, and I will explain why. Farmers plant wheat in the fall right after they harvest the soybeans from the same field. The wheat seed then goes dormant during the winter and begins to germinate when the ground starts to warm up in the spring. It takes about 4 months (give or take a few weeks) for the wheat to reach maturity and then dry down enough to be harvested. (Generally around July 4th in central Indiana, but it changes based on the latitude. The farther south you are the earlier it happens due to a warmer climate.) But there a possibility that if all the farmer did was wheat, and the climate was perfect that you could theoretically do two wheat crops per year, but that doesn’t happen in reality.

4. What kind of baling machine is used?Any baler can put hay or straw into bales. There are three main types of balers: Round balers, Small square balers, and Big square balers. Round bales are used primarily for hay, and seldom for straw, there is no real reason for this other than that they don’t stack as space efficiently as square bales do. Round bales are typically either 4’x5’ or 5’x5’ in size. The overwhelming majority of wheat straw is put up by small square balers which ideally have a bale that is approximately 1.5’x1.5’x3.5’ (LWH). The straw bales typically weigh somewhere in neighborhood of 35-45 pounds for the ones that are tied with strings, and 45-75 pounds for wire tied bales. String tied bales are much more common because the consumer doesn’t have to worry about the random wires all over the place, and you don’t have to have pliers to open the bale up, just a pocket knife will do for the string bales. The weight difference is because of the tinsel strength of the wire itself over twine (string) before it breaks, thus making the bales much more compact/dense than twine bales. The last type of baler that is sometimes used is a big square baler. These bales are generally 2.5’x2.5’x5.5’ (lwh), are much more dense, always string tied I believe?? and generally weigh about 400-500 pounds. These are not as common with construction, and primarily used for animal bedding simply due to the fact that you must use a skid loader or tractor with a loader on it to move them. The most common manufacturers of balers are: New Holland, John Deere and Case IH. Our personal baler is a New Holland 275.

5. Are there many, if any, different kinds of balers. (beyond hand and mechanized)I think I just answered this question in number 4, but if I didn’t please let me know and I will do what I can to answer it. Nobody does anything completely by hand anymore though, it is all put into bales by machines.

6. How customizable are bales using this machine? Can you do different densities? Can you do different heights, widths, lengths?I don’t think that round bales are very customizable but I am not certain of that. Both sizes of square bales are customizable to some degree, but mostly the only things you can change is the length of the bale and how tight the strings/wires are on them. However changing either of these increases the total volume of the bale. To simply increase density though all you have to do is increase the tension adjuster on the baler. But the height and widths of the bales are what they are simply due to how the baler is constructed.

59

appendix

53

60

7. Is there a certain “fudge factor” to the machine?There is not an intentional fudge factor. Not all bales are exactly equal for multiple reasons, but most should be very similar if the baler is working correctly.

8. Why type of string/wire do you use to hold the straw together?I have never been around a wire tie baler so I can’t speak for the specks on it, but just like string there is a special type that comes in spools that you just have to hook up and start baling with. Our baler uses a string just like this, but it doesn’t have to be this brand as long as it is a Sisal Fiber twine it will work fine with our baler (and most small square balers)http://www.tractorsupply.com/twine/countyline-reg-square-baler-twine-9-000-ft--1429142The round balers and big square balers all use pretty much the same type of string, but it is a smaller diameter than for smaller squares. But to compensate for that, these bales have many more strings/bale than small squares do. (Small squares have two strings)

9. Is there a typical size of bale that you make? Is there a reason for this?

5554

61

This was answered in number 4. And the reason for the size in small squares is that it is the easiest to stack and store in a barn. The size increase of round and big squares is simply to get more straw/hay per bale.

10. When storing bales, is there a specific way in which they are stored/stacked? (lines of bales, big stacks, small stacks, single “towers” of bales, or other?) and what is the reason for storing/stacking them this way?Yes there absolutely is a good way and a bad way of stacking them. You always want to put wooden pallets under the first layer so that the air can circulate around them if you are doing hay. But if you are doing straw it doesn’t matter as much because they are typically dry enough anyway and don’t need as much circulation. As for the actual stacking of the bales, you want to put the bottom layer long-ways so that the length of the bale is parallel to the inside of the barn. Put another one on the end of it, butted up together and so on until you get to the end of the barn. Then put another row running the same direction in front of the first row so that the bales are “two wide”. After completing this second row, begin putting the second layer on top but make sure to put these bales perpendicular to the first layer (smaller end towards the barn side) thus you can tie the bales together and they are less likely to fall or shift. I’ll try to draw what I’m describing to you.

appendix

5756

The only difference between this and the real thing is that you don’t want spaces between the bales, you want them as close together as you can with the strings up so that you can grip them easier and they stack closer/tighter. The first arrow represents the first layer. The second arrow represents the second layer which is placed directly on top of the first layer. You can probably see how the bales will interlock each other and help stabilize everything.

11. What do you use the bales for? If you sell ALL of the bales, who is your typical customer and what would the typical use for these bales be?We do not sell all of our bales of straw. Typically we keep around 150-200 to use for bedding for our cows and horse and maybe for the dogs if it gets really cold. However we generally sell about 1200+, and those that are sold go to either construction companies or to horse racers who use it for stall bedding

62

5958

12. Are you familiar with bales being used in construction?I do not know all the details of straw use on construction sites, but I have had a Natural Resources class at Purdue that discussed its use as a surface cover on soil that has no vegetative (grass) cover on it to help prevent various types erosion. Additionally I know that there is some large machine that you put straw bales into that chops them up and blows them out on the ground to save time and increase efficiency (similar to that of a snow machine). But other than that I don’t know anything else.

13. Have you ever sold bales to be used for construction? What are some differences in the processing of the bales for this use?I believe that we have sold bales for construction use in the past, but am not certain. But regardless, there is no difference in the process that goes into the production process. We demand that all bales meet a certain set of standards if they are to be sold, so that we keep a good reputation of having quality products.

63

appendix

6160

64

Book ReviewsBuilding with Straw Serious Straw Bale This book explains in detail - also in great diagrams/drawings - different assemblies and the structure and physical aspects involved in straw bale construction. This book is a great reference for learning some of the many different details seen with straw bale construction. It includes graphs and numbers to explain the different finishes. The second half of the book is packed full of straw bale projects, each with images and a description. This book is from the UK and they have provided unit conversions in the back as the numbers in the charts, diagrams, and drawings are metric. A great book to have for self-builders.

This book talks all about straw bale walls. This is a great first read for anyone being introduced to straw bale construction. The authors walk you through the history and along the way they provide example projects to back up points they make. Another great book filled with images and detail diagrams. They explain some of the best practices with construction and they do so in layman terms. This book has more of a focus towards extreme climates as they are likely to have a higher amount of environmental stresses on the building.

6362

65

appendix

Design of Straw Bale Buildings The Straw Bale House This book is a comprehensive look into straw bale as a building material. It does a great job of cutting through the breadth of the topic. They cover structure, moisture, insulation, fire, acoustics, plasters, detailing, and codes and standards. Like the other books, this book also provides plenty of images, diagrams, and graphs. Another great source of information for those new to this topic. The biggest contribution of this book, in my opinion, is the section on structures. Even if you aren’t an expert in structures, the authors do a wonderful job of explaining the entire section.

Similar to a couple of the other books, this book breaks down straw bale construction and in detail describes each of them. From foundations and roofs to windows and doors and even benefits and concerns. The authors put their hands around the straw bale construction world with this book. Like other books on straw bale, images and example projects are provided along the reading the help illustrate points.

6564

66

Passive Solar Architecture Green Studio Handbook This book is a comprehensive introduction and guide to the subject of passive solar architecture. Both of the authors have been working the passive solar field for roughly 40 years. They use colorful images, tables, and diagrams and also have helpful illustrations for making different points. The book is divided into major categories which are easily found. A must read for students in the architecture field.

Just as the title suggests, this book is a handbook. It’s a great reference for quickly learning about the differences between different technologies. The book gives quick, but full, explanations of the many technologies. It goes on to show how to design with them, providing sample problems to go along with the design procedures. At the end of each of the sections, they provide a bit on where to find more information on each piece of technology. The book has nice pictures and diagrams. Another must read for architecture students.

6766

67

appendix

68

Adobe is a mud brick that can be sun-dried. It is the oldest known, and still the most common, building elements used. It is on the opposite end of the spectrum of straw bale. Bales are complete blocks of straw while adobes are nearly pure blocks of clay and sand.

A baler is a piece of agriculture machinery which is used to compress a cut and raked crop into compacted bales. The baler ties the bales together with some sort of twine, strapping, netting, or wire. These bales are much easy to handle, transport, and store as a result.

Cob is thought of as heavy straw-clay because it has much more clay and sand than straw and does not require a wood frame or form work. Lumps (cobs) of material are packed and sculpted by hand into walls and vaults.

Hay is grass, legumes or other herbaceous plants that have been cut, dried, and stored for use as animal fodder. Hay and straw both include the plant stalk but hay also includes the grain, which has the protein and carbohydrate-rich fruit of the plant. Hay is typically fed to animals when grazing is unavailable due to weather or when animals are unable to access pasture. “Hay is for horses.”

Laid-flat refers to when a bail is positioned so that the heat flows parallel the length of the straw or “with the grain.”

Laid-on-edge refers to when a bail is positioned so that the heat flows perpendicular to the straws or “against the grain.”

Nebraska-style construction is the method in which the straw bale walls are load-bearing. Load-bearing means that they support the weight of the roof and transfer its load to the ground. It’s name comes from its invention in Nebraska in the late 19th century.

R-value is a numerical measure of resistance to the flow of heat. The higher the value, the more resistant a material is to the flow of heat and the higher the thermal performance of the material. The building industry came up with this number as we tend to think “bigger is better.” R-value is the inverse of U-value.

Render is term which refers to a finish applied to a surface, typically a wall. Typical materials used for render are: plaster, concrete, clay, and earth.

Straw is an agricultural by-product. It is the dry stalk of cereal plants, after the grain and chaff have been removed. Chaff is protective covering around the seed. Straw is gathered and stored in bales. Bales may be square, rectangular, or round, depending on the type of baler used.

Definitions

69

appendix

Straw-clay involves mixing straw with clay and packing it into or onto a wood frame. A method called wattle and daub uses a straw-clay mix that is packed around a basket-like weave of reeds, cane, bamboo, or wood. Another method involves densely packing straw soaked in a light clay slip between the timbers of a wooden frame.

Thermal bridge (sometimes called “cold bridges”) denote patches on walls or roofs that have a significantly lower thermal resistance than adjacent areas. It means that the heat transition from the inside out is substantially higher and as a result the higher heat loss can cause moisture problems in these ares.

Thermal mass is the quantity of heat energy that a building is capable of storing. The idea behind thermal mass is that it helps regulate the temperature of a space, absorbing heat while the “heater” is turned on and releasing the heat slowly once the “heater” has been turned off. For example, while the sun is beating down on a building and into the interior spaces, a building with no thermal mass would heat up as the materials would not be able to store heat energy. A building with thermal mass would ideally absorb the heat energy in order to keep the interior space from overheating, then once the sun has gone down, it releases the heat energy to help keep the space warm during the night time.

Toe-up refers to the elevated platform that the bails sit on. This can be made of different materials. Typical methods for doing this include: 2x3’s with a rigid insulation between them, a couple of masonry blocks, or a knee wall. In any of these cases, the goal is to raise the bails from the floor to ensure that they do not soak up any moisture from the slab.

U-value is the numerical measurement of thermal conductance. It is the number of British Thermal Units of energy (Btu) that will flow through 1 square foot of a material during one hour (at whatever thickness the material is) with a one degree Fahrenheit difference between the air temperatures at the two sides of the material. The lower the value, the less heat is conducted and the better the thermal performance of the material.

Vapor diffusion refers to the tendency of water vapor to move from high pressure areas to lower pressure areas. A good example of this can be seen in the winter. The warm house will have a higher vapor pressure than the outdoor condition, therefor the vapor will want to move from inside to outside. Because the vapor will tend to move through the building assembly, there are a couple different ways to deal with this. First, you can install a vapor barrier to ensure that the vapor cannot enter the wall. Second, you can construct the assembly so that the vapor can continue moving through the wall. This second approach is referred to as allowing a wall to breathe.

70

photo taken by Paul Reynoldshttp://www.shortstopblog.com/2009/10/peek-inside-our-monday-mornin-window.htmlhttp://www.thegreenestdollar.com/2008/11/building-a-straw-bale-home/photo taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynolds

0102030405060708091011121314151617181920212223242526272829303132333435

Image Credits

credit

71

photo taken by Paul Reynoldshttp://ecocenter.iweb.bsu.edu/lightbox1/lightbox/process.htmhttp://www.gregorylehman.com/houses/gallery/strawbaleTop.phphttp://www.spfa.com/HTML/haybarnDESCRIPTION.htmphoto taken by Paul Reynoldshttp://www.archinnovations.com/featured-projects/houses/sarah-wigglesworth-architects-stock-orchard-street/http://www.baubiologie.at/handwerkersuche/projektgalerie.html?id=115&partner=0Minke, Gernot, and Friedemann Mahlke. Building with Straw: Design and Technology of a Sustainable Architecture. page 83Minke, Gernot, and Friedemann Mahlke. Building with Straw: Design and Technology of a Sustainable Architecture. page 104Minke, Gernot, and Friedemann Mahlke. Building with Straw: Design and Technology of a Sustainable Architecture. page 106Minke, Gernot, and Friedemann Mahlke. Building with Straw: Design and Technology of a Sustainable Architecture. page 97http://www.arkintilt.com/projects/public/arastradero.htmlphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldsphoto taken by Paul Reynoldshttp://www.awtscale.com/Product_detail.html?id=74http://it.wikipedia.org/wiki/File:Straw_bales_in_field.jpghttp://andrusiwfarm.8m.com/index.htmlhttp://cattlekids.blogspot.com/2011/07/hauling-hay-and-breaking-horses.htmlhttp://commons.wikimedia.org/wiki/File:Fiat_130-90_with_straw_bales_on_trailer.jpghttp://wagnerfeed.blogspot.com/2010_08_01_archive.htmlhttp://www.infrawindow.com/eco-development/rock-stone-bamboo-building-materials-for-the-green-age-part-2_103/http://www.escapenormal.com/category/cheap-living/http://blog.gaiam.com/blog/gaiam-staffers-red-feather-build-straw-bale-homes-for-good-people/http://www.buildingwithawareness.com/house1.htmlMinke, Gernot, and Friedemann Mahlke. Building with Straw: Design and Technology of a Sustainable Architecture. Cover ImageLacinski, Paul, and Michel Bergeron. SERIOUS STRAW BALE: A Home Construction Guide for All Climates. Cover ImageKing, Bruce, and Mark Aschheim. Design of Straw Bale Buildings: The State of the Art. Cover ImageSteen, Athena Swentzell., Bill Steen, David Bainbridge, and David Eisenberg. The Straw Bale House. Cover ImageBainbridge, David A., and Kenneth L. Haggard. Passive Solar Architecture: Heating, Cooling, Ventilation, Daylighting, and More Using Natural Flows. Cover ImageKwok, Alison , and Walter T. Grondzik. The Green Studio Handbook: Environmental Strategies for Schematic Design. Cover Image

36373839404142434445464748495051525354555657585960616263646566

67

72

Bainbridge, David A., and Kenneth L. Haggard. Passive Solar Architecture: Heating, Cooling, Ventilation, Daylighting, and More Using Natu-ral Flows. White River Junction, VT: Chelsea Green Pub., 2011. Print.

Guzowski, Mary. Daylighting for Sustainable Design. New York: McGraw-Hill, 2000. Print.

King, Bruce, and Mark Aschheim. Design of Straw Bale Buildings: The State of the Art. San Rafael, CA: Green Building, 2006. Print.

Lacinski, Paul, and Michel Bergeron. SERIOUS STRAW BALE: A Home Construction Guide for All Climates. White River Junction, VT: Chelsea Green Pub., 2000. Print.

Minke, Gernot, and Friedemann Mahlke. Building with Straw: Design and Technology of a Sustainable Architecture. Basel: Birkhäuser, 2005. Print.

Steen, Athena Swentzell., Bill Steen, David Bainbridge, and David Eisenberg. The Straw Bale House. White River Junction (Vt.): Chelsea Green Publ, 1994. Print.

“Strawbale: The Baling Process.” E-mail interview. Oct. 2011.

References

73

references