The Pros and Cons of Straw Bale Wall Construction In Green Building


Following are some pros and cons of building a straw bale house. Like any building material, it is always best to evaluate your needs and your goals before committing to a particular material. Green building offers a wide range of options in achieving energy efficiency. When appropriate for your project, straw bale construction has many benefits.

Advantages of straw bale construction
1. Straw bales are made from a waste product. Once the edible part of the grain has been harvested (such as wheat or rice), the stalks often become a disposal problem for farmers. By bailing the straw, a new life is given to the material. The farmer makes some money by selling the bales and the homebuilder gains an excellent insulation and building material.

2. Homes insulated with straw bale can have insulation values of R-30 to R-35 or more. The thicker the bale, the better the R-value.

3. Straw bale walls are at least eighteen inches thick. This adds aesthetic value to the home as thick wall are expensive to achieve with conventional construction. The thickness of the wall helps to reflect sunlight throughout the room.

4. Due to the thickness of straw bale walls, every window can have a window seat or shelf. This becomes both an aesthetic and practical design element.

5. The concept of straw bale construction is easily understood by even novice builders. With supervision by one knowledgeable straw bale trainer, first-time builders can assist in the construction process. This not only spreads the word about straw bale construction, it also means that the homebuilder can save money by using a volunteer crew to help raise the walls.

6. Straw bales have a low-embodied energy. This means that very little energy was used to manufacture the product as sunlight was the main energy source for growing plant. The only energy needed to make a straw bale is in the bailing process and the transportation to the worksite. Other insulation materials, such as fiberglass, require a substantial amount of energy to produce.

7. Straw bales are 100% biodegradable—when the time comes. Straw Bale homes can last over 100 years if properly maintained. At some point, all structures will eventually be replaced. When the time comes, the straw bales can be plowed back into the earth. Fiberglass, on the other hand, becomes a disposal problem.

8. Straw bale walls can be carved with a knife or chainsaw. Openings around windows or doors can be bullnosed to a nice radius. Bales can also be finished to a sharp angular edge. Nichos can also be carved into the bales.

9. Despite what might seem logical, properly constructed walls made from straw bales have proven to be more flame retardant than conventional wood-frame construction. This is because the bales are dense and tend to just smolder when the ignition source is removed.

10. Straw bale insulation is the most effective in climates where heating and/or cooling of the home is essential for comfort.

11. Straw bale homes can be beautiful as the natural material lends itself to multiple architectural styles.

Disadvantages of Straw Bale Construction 
1. SInce it is not a conventional building material, the contractor or do-it-yourselfer will need to learn new construction techniques. Although not difficult, they are different.

2. If straw bale building codes are not part of your local codes, it may be a bit more work to get your plans approved. Contact others in your area and see if they can suggest local architects or engineers that are used to working with natural materials and see they can stamp your plans and help with the approval process.

3. Straw bale walls need to be kept dry as moisture is detrimental to not only straw, but to many building materials. Moisture entering the bales from the roof above is to be avoided at all cost. If the walls of your straw bale home are kept dry, they will last for the life of the building.

4. Areas of extreme humidity and rain my not be appropriate for straw bale construction.

5. Due to the thickness of the walls (usually around 18-20 inches), more of your overall square footage will be unusable due to it being within the wall space.

6. If straw bales are not available within a few hundred miles of your construction site, the cost of shipping them, along with the potential pollution from the transportation, must be taken into account.

If you would like to learn more about straw bale home construction, take a look at the DVD video and book  called “Building With Awareness: The Construction of a Hybrid Home.” It is available online and in book stores.

Article and photo by Ted Owens

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31 Responses to “The Pros and Cons of Straw Bale Wall Construction In Green Building”

  1. Linda Watkins Says:

    Thanks, The info. was helpful. I am thinking of building a staw bale home on my 5 ac. east of Mt. Shasta and North of Mt. Lassen Ca. It would be helpful to find out if there is anyone in this area that can help with the overseeing or contracting of this home. If you have any info. for me contact me though this blog please. Linda

  2. Brandon Eller Says:

    Like Linda, I am also thinking of building a straw bale house/shop in northern California, specifically Cedarville. Your blog is very inspiring, and I appreciate your insights on green building. Linda, if you are still looking for help, I can offer my time in exchange for the opportunity to learn. I am a carpenter by trade.
    Brandon

  3. sue Says:

    is north east tn considered a good location for this type of building?
    ty sue

  4. Ahmed Bilal Says:

    Thanx for the info. i am planing to build Straw bale houses in Pakistan, how do u think the Moon Soon rains would effect them??

    AB

  5. dennis Says:

    i live in south eastern indiana and it is very windy humid and we get alot of rain could someone tell me if it would be a bad idea to build a straw build house straw is abundunt here and i have the skills to build it but im afraid of all the rain and humidity i live in the middle of a corn field

  6. Ari Says:

    Couple of issues with this blog post:

    1. You stated under “pros” that the “thickness of the walls helps reflect sunlight throughout the room”. Please explain this, as it makes little/no sense at all to me.

    2. Under cons, you claim that a large amount of overall square footage being unusable due to the pace being taking up by the walls. This too makes no sense, as the individual designing/building the structure would obviously take into account the area taken up by the thicker walls — in other words, the thickness of the walls makes no difference with regards to the interior floor space of a house, when it is being built new. On the other hand, if you are adding straw bale interior walls to an existing structure made of straw bales, this could be a problem. It could also be a problem if the lot you’re building on is particularly small, such as in New York City or something like that, where the houses tend to take up the entirety of the buildable lot. But I kind of doubt that straw bale houses conform to NYC building codes in the first place.

  7. Gabrielle Says:

    My husband and I are attempting to purchase a home with straw-bale insulation and are running into lending hurdles: very few, if any, lenders want to back a home like this. I would appreciate any assistance you may be able to offer.
    Thanks!
    Gabrielle

  8. Sarah Says:

    Is there a way to know if buying a straw built home if the walls have had water issues?

  9. adrian Says:

    I’m living in Romania and for decades the rural communities here where made by straw,or brick of mud,manure and straw and many combinations like these.Such houses still exist.The construction method here depends now on only steel,concrete and poor architecture.I believe that you can post another disadvantage on your list,and that is the people’s open mind.It’s a good laugh around me when i bring up these construction methods,but still Ï believe that straws and local materials in combination with new methods and materials of the present are the future.So thank you for the information and hope that you will someday read about straw houses in Romania.(it shallll be mee) :)

  10. Amy Mathes Says:

    Thinking of building a straw bale home in Oklahoma, but how well do these homes stand up with straight line winds or small tornado’s? Would the straw affect people with allergies?

  11. Reginald C Says:

    Hello there. Good write up you have written above. For me personally, you have nailed all the important facts and I have even bookmarked them for future usage. Continue the good work and many thanks for discussing the stunning information!

  12. Chea O'Hanlon Says:

    This infomation was very usfull

  13. Chea Says:

    Thank you, this information was very useful. I have a friend who is thinking about building a straw house and she was wondering what the advantages and disadvantages were. I will show her this.Chea

  14. monica Says:

    Thanks for your info Linda..Since my proposed cottage is in a rain forest, hay bales will not work!

  15. Rainy Says:

    What about pests? I know some straw bales can have grain still on them, could that encourage rodent or bug problems.

  16. Eddy Wilbers Says:

    Two years ago, I purchsed a straw bale home in Minnesota. When I closed the house was in poor shape and the exterior had to be rebuilt. Our first winter in the house was cool and drafty and we were spending a fair amount on heat. We did as much research as we could, but we have struggled to figure out exactly how we should fix and maintain our home.
    Fortunately when we removed the old rainscreen the bale was in good shape. It had not been plastered and the bale had settled in some places leaving air gaps. We repacked the gaps before residing the house with Hardiboard. There is a Tyvek moisture barrier between the bale and the siding, but the bale remains unplastered.
    I thought that this would make a big difference in our heating costs, but last winter we continued to spend much more than we anticpated to heat the home. I suspect that the bale in the roof has settled as well, but I am loath to remove the tin roof to fix the bale.
    I was wondering about blowing some kind insulation into the gaps. I also had an energy audit done on the house and they found that the house exchanges air 11.6 times per hour. The second floor ceiling is rough beam and there are gaps between the beams. On top of the beams there is a layer of felt beneath the bale. The inspector recommended caulking between the beams to help reduce the air exchange. I am worried that this could cause moisture to build up under the bales in the roof.
    I would really like to shore things up before the snow flies again in order to reduce our natural gas usage this winter. Any advice would be appreciated.
    Thanks,
    Eddy

  17. Chris Says:

    I don’t understand this argument:
    “The thickness of the wall helps to reflect sunlight throughout the room”
    How are reflective qualities of a material influenced by its thickness?

  18. Ted Owens Says:

    Hi Chris. Good question as I see how that could be confusing. Due to the walls being eighteen inches thick, all the window openings have around sixteen inches of an inset when the windows are installed to the outside surface. The window seat then acts as a light reflector to the ceiling and the side walls of the window opening reflect light to the left or right side of the room, depending on the angle of the sun. This sixteen—to—eighteen inch inset helps to diffuse and scatter light around the room. With a conventional frame wall, the inset around the window would only be a few inches and would not bounce much light around. It is the thick straw bale wall that forms an inset box around the window.

  19. Rose Tsenase Says:

    Good alternative building material but under the disadvantages you forgot to mention that is not fire resistance.

  20. Maria Montesinos Says:

    Hi Ted

    Do the inside walls need a foundation too? I have seen many pictures of straw bale and mud constructions and I see they have the frame only but inside they are beautifully decorated with walls, etc.

  21. Maria Montesinos Says:

    I am planning to build in South America, the climate is always spring there, the sunshines almost all the time and it is not humid is dray. How long would you think I need to build a house (1 floor) of around 800 sq. ft. I will hopefully find enough help to do this. Please advise

  22. Maria Montesinos Says:

    I forgot to ask what heavy construction equipment would we need to i.e. to mix the mud, to build the wood frame, etc.
    Your comments will be grately appreciated.
    I am also proceeding to buy the DVD and the book :)

  23. admin Says:

    Mud can be mixed by hand in a wheelbarrow, however renting and electric mixer is much easier and is worth the cost. Wood-frame construction can be done with basic woodworking tools such as hammers, skill saws, etc. and does not need heavy construction equipment for most construction. All of this is covered in further detail in the book and DVD.

  24. admin Says:

    It all depends on how many people you have to help you. The more you have, the faster the home can go up. typically I would say to allow at least nine months with a permitted home that includes water, power, and basic conveniences. It could take a couple of years if you are doing most of the work yourself.

  25. admin Says:

    Almost all walls require some sort of foundation. Many times interior wall foundations are not visible and the floor slab is thicker under the walls. Code requirements will determine all of this.

  26. admin Says:

    A properly constructed straw bale home should as fire resistant as typical wood-frame construction.

  27. admin Says:

    A well-constructed straw bale home should have no more pest problems than conventional frame construction. If properly constructed, pests will not have any access to the straw bales themselves as the walls are sealed on both sides with mud, plaster, or stucco.

  28. admin Says:

    Always consult a local expert to deal with weather conditions in your area. Tornados would be a challenge for most structures. As far as allergies, the only problem would be during construction when there is a lot of dust flying around from the straw. Once it is plastered on both sides, allergies should not be a problem. At least that is my experience.
    —Ted Owens
    Director: Building With Awareness

  29. admin Says:

    It is possible to check for the moisture content within the bales by using a long probe that can be inserted into the walls. A quarter inch hole would have to be drilled to insert the probe. It is like a very long version of the moisture meters that are used for checking indoor house plants. Other than that, you would have to check for visible signs of water damage on the outside of the walls. You could also ask the owners if they had any photos that were taken during construction. You could then see if there is at least a waterproof barrier on the top bale that would protect from roof leaks.
    —Ted Owens

  30. Steve Says:

    I was under the impression that straw bale construction saved a lot on energy but I’ve read posts that state they do not see these savings. So I wonder if there’s a particular piece of the construction process they might be missing. Any thoughts on this?

    Also, I’m no expert so, exactly how does one replace the disintegrated straw bale after 100 years without entirely disassembling the home? Wouldn’t you need to disassemble the exterior wall and access the top of the bale wall by removing the roof? I don’t get it. :)

  31. admin Says:

    Like any structure or building material, the ultimate energy efficiency of the home will depend on how well it is built. Straw bale makes for an excellent insulating material that also happens to be very environmentally sound. If you use sloppy building techniques (air gaps in the walls and around doors and windows, poor foundation insulation, etc.) and fail to build a well insulated roof that is also free of air leaks, the straw bale walls will be of little value, as would any other insulating material.

    If a bale needs to be replaced in my home after 100 years, I will gladly turn the project over to a younger expert. ;-)
    —Ted Owens

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