Ten Tough Questions Answered

Written by Andrew Morrison

I recently asked a bunch of you to send me your toughest straw bale question. I had about 200 people answer the call and I thank you for writing in. Below are the answers to the top ten of those questions. Some of these questions are compilations from many questions as some of you asked similar questions that were best answered in one shot. I hope you enjoy the question and answer session!

Q: Is straw bale construction limited to right angles or can more organic shapes be utilized? It seems that nature points towards organic shapes like curves, rounded edges, and soft lines yet most of the homes I see are built to conform to squares or rectangles.

A: It’s true that nature suggests more organic shapes in the way it builds. Paul Simon says it best in my mind: “Nature gives us shapeless shapes of clouds and waves and flames. But human expectation is that love remains the same.” To me, this sums up how we as humans tend to change things to fit our needs as opposed to allowing our needs to be met by what exists around us.

The answer is in short yes, bale structures can be built in organic shapes. In fact, they do a really god job of building organic shapes because they can be molded, reshaped, bent, and fitted to almost any design. The difficulty comes with the rest of the structure. For example, if you have a curved wall that has six windows in it, how do you deal with the curve of the wall and the flat of the glass? How about the roof structure? Roofs are hard enough to build when the structure beneath them is a rectangle, but if you start throwing organic shapes into the mix, they get even harder.

So it often becomes about the bottom lines: cost and level of difficulty. It seems that the human race of today’s modern culture (generally speaking) is looking for the least expensive way to do things with the least amount of effort. Some call it frugal, others call it lazy. Whatever you call it, the trend seems to be toward creating simple houses that border on downright boring.

I say, build organic! Stretch the limits of what your neighbors think is possible. Here’s the caveat though: build it well. The other side of the boring house syndrome coin is the folks that build really cool looking stuff that falls down in a year or ten because it was not built right. That only hurts our chances of breaking away from the square trap. There are some folks out there who are building amazing organic structures to excellent standards of quality and I applaud them for it. I hope more of you join that team!

Q: What about different building details like parapet roofs, inset windows or even flat roofs? I like the Southwest style architecture and would like to utilize that in my design. I also like the idea of having a deck over my living space, thus the flat roof, that my wife and I can enjoy for evening sunsets.

A: Flat roofs, parapet roofs, and inset windows are all interesting design features and ones that I recommend against using. Let’s start with the roofs. Parapet roofs are similar to flat roofs, but are not actually flat. They have a slight slope to them behind the parapet wall, and they drain towards the exterior perimeter. The risk here is that all of the water that collects on the roof structure ends up draining out of scuppers (roof drains) in specific locations. The water runs towards the perpendicular intersection of the parapet wall and roof and then runs along that joint to the closest scupper. Can you picture the potential for risk here?

Let’s imagine that the nearest scupper has a bird’s nest in it or is otherwise clogged. Where does the water go now? It will continue down the intersection until it finds the easiest way out. That could be the next scupper down the line or it could be a nail hole in the flashing detail. It could potentially drain straight down into the bale wall, and without you knowing it for a long time.  Since bales are like giant sponges, they will soak up as much water as they can get until they reach saturation, at which point, you may discover you have a leak. Of course, at this time, it’s too late.

Flat roofs have the same issues of potential leakage; however, they generally don’t have the wall/roof intersection on all sides. Sometimes they don’t have it at all. The biggest issue here is the potential for standing water to find its way in through the waterproof membrane as described above. A single nail hole could do the trick.

Another issue with both flat and parapet roofs is that there is usually no overhang to protect the walls from driving rain. This means that your only line of defense against the forces of nature is the plaster. That’s not enough. Lime plaster, my personal favorite, has a relatively high capillary action and so will actually absorb moisture. This is a good thing as it helps to draw moisture out of the bales; however, if under constant barrage by the weather, the amount of moisture in the lime may soon be too much for it to handle and the bales may start to draw moisture from it instead.

Inset windows can be done with more confidence than the flat or parapet roofs, in my opinion. Special adhesive flashing details need to be used for this to work well. Remember, you’re relying on your flashing 100%. If it fails, the window plane is directly above the top, FLAT surface of the bales. A leak here will drain into the top of the bales and that’s a hard leak to discover until it’s too late. I believe I already have the cross sectional diagram for how to flash this style window on the site. If not, let me know and I’ll post it. (I would check but I’m currently in the car driving to my son’s hockey tournament and have no internet access here!)

Q: I want to build my house in a humid climate. Is this a problem? If it’s possible, what changes do I need to make to my design to accommodate the humidity and wet climate in general?

A: Humidity is certainly more of an issue than rain. That’s because rain can be completely designed out of the equation. A wrap around roof or other structural design element can keep rain completely off of your walls; however, humidity finds its way into every inch of your structure no matter how big the roof.

In recent months, I spoke with a number of people who live in bale homes in the Southeast and they reported back that the humidity there has not been an issue for them. I taught a seven day workshop in Tennessee in July of 2010 and was shocked to see how well the bales did in the highly humid climate. Each morning, mid day and evening, I would measure the moisture content of the bales with my bale meter and I was amazed to see how consistent the readings were, always below 15%.

As much as bales have the ability to absorb and release moisture, they can always use a little help, especially in highly humid climates. The inclusion of a Heat Recovery Ventilator (HRV) is a great idea. This machine will constantly circulate fresh air into the house without losing the conditioned properties of the air it expels to the outside. In that process, it pulls excess humidity out of the air and drops it outside the home via a condensation line. This is a great help.

Other design elements to consider are placing the house properly on the site so that you can take advantage of prevailing winds, which can help to dry out the house. Equally important is the design of the house to receive the drying effects of the sun. The more passive design elements you can include to help you handle the added moisture in the air, the better. The use of the HRV should be considered a back up to the passive elements, in my opinion, since you never know when the lights might go out for a stretch of time. If you’re too dependent on the mechanics of your house, you might be in trouble during an extended power outage.

Q: If straw bale construction is so great, then why aren’t more people doing it?

A: This question really caught my eye. Sometimes I find it hard to believe that more people haven’t jumped on the straw bale train too. We all know the benefits of building with bales: super efficiency, sound proof out the wazoo, beautiful, environmentally sound use of materials, fire resistance, and on and on, yet, they’re still not very common in most communities. So why is that?

I think there are a number of reasons that play into this. The first and biggest is that the general public does not like change. The masses move slowly. This has been true throughout history and is no different today. If someone told you that the best thing in the world to build a house out of was used sweat socks, would you believe them? How about if you heard that from 10 people, 100 people? Eventually, you might start listening, but it would take a while for you to jump in, I imagine. It’s the same with straw bale construction. For those of us who know about it and understand it, it’s simple, but for those who are just hearing about it, it may sound crazy.

That leads me to my next point: not enough word of mouth in the larger circles of the world. For too long straw bale construction has been the secret child of a select few. I’ve heard many people within the straw bale community say that straw bale will never catch on within the main stream. There are two problems with this statement. The first is that it is self-defeating. If I don’t believe that something can happen, then how can I move towards helping it happen? In my mind, I can’t.

The second “problem” is that of “the straw bale community.” If we knit ourselves into a comfortable, yet tight ball of yarn then we can’t reach out to those on the outside. The fact of the matter is that it’s the folks on the outside of that circle that most need to hear about what we’re doing. Otherwise, we’re just shaking each other’s hands and smiling at those who already agree with us. I want us to reach further. It will be uncomfortable and it will probably stir some waters and make some people unhappy, but in my opinion, this is not about a small group of us happy. It’s about providing the world with sound, environmentally responsible building practices.

Q: How do you find restraint from strangling the endless parade of people who ask: What about fire and mice and the pig thing?

A: This was too funny not to include and it fits into the last question pretty well. To me, this is about education, once again. I have answered those questions so many times, you can hardly imagine. I always answer them with a smile on my face because I realize that each person I answer the question for is one more person who may be able to see the value of straw bale construction. Some of them are trying to show me that I’m crazy. That’s okay, I know how amazing this stuff is so I don’t worry about them convincing me of that.

If straw bale construction were seen more prominently in the mainstream media, most of those silly questions would go away. I figure that the existence of those questions is a good gauge for how well “we’re” doing at spreading the word to the larger public. The less I hear that question, the better we’re doing. Each time I hear them, I can see where we need to be more vocal, more in the public eye.

Q: Can I use straw bale to retrofit my old house? I don’t want to knock my old house down just to build a new one. I’d like to use some of the existing structure to my advantage.

A: This can certainly be done. There are some things you’ll need to consider when retrofitting an existing house.

1.     Is the existing house design such that you can stack the bales on the inside of the existing frame? This would allow you to salvage most of the framing, plumbing, and some of the electrical. It would also minimize the amount of additional work you’ll need to perform to accommodate for the bales.

2.     If you have to stack the bales outside of the existing frame, can you easily build a new foundation to support the bales and a roof to cover them?

3.     Will you need to move windows or doors from their current location? Wall openings should be flush to the outside, in my opinion, so if you have to extend the bales to the outside of the existing frame, then you’ll have to move your windows and doors to the outside of the new wall plane created by the bales.

4.     Will you keep your original siding or replace it? If you replace it, what will you use? The type of siding will affect the way you stack your bales to some extent. For example, bales stacked tight to the interior face of the original framing (avoiding notching) would not provide adequate support for plaster so you would have to provide some other way of siding the structure.

As you can see, there are a lot of details to consider and each project will be different. The key is that it is possible and in many cases is a good idea. Some houses will be better knocked down as the amount of work they take to use in retrofit will be more than the value you get from saving them. In these cases, consider donating your house to the local police and fire departments for training. I don’t mean give them your house. I mean let them use the house.

I did this a number of years ago and it was a blast. My friends and I got to role-play against the SWAT team while they trained on hostage situations. We were the bad guys! After we were done, I had the fire department come in and use the house for a week of on-site training that culminated in a “burn to learn” training of actually burning the house to the ground. I should say that before either of these departments came in, I allowed the local building material salvage guys in to take what they wanted. That way, anything worth reusing was pulled from the house before it went up in pepper spray and then smoke!

Q: How do I find a lender that will work with me on my straw bale structure?

A: This has gotten a lot harder in recent years because of the financial downturn. I place a lot of the blame for the downturn on the lending industry to begin with for making loans on projects that should never have received financing, so to hear that industry tell us that our projects are too risky is very frustrating. That said, that is often the words we’re given by lenders. This is, once again, a question of education.

Perhaps you can find a lender willing to receive an education from you about the merits of straw bale construction. Most likely not, but I always suggest you try. If you have say 5 lenders in your area that you might be able to work with, tell a few of them exactly what you plan to do and why they would be smart to lend to you. Let them understand that this is a growing industry and they would be smart to take the lead in the field. Be known as the “go-to” company. Speak to their bottom line and you’ll likely have more luck than if you try to talk to their lender brain. No offense to lenders, but in general, they are charged with protecting the company’s bottom line and so anything outside of the very small box they are handed is often tossed out without a second glance.

There are “green lenders” out there and they are obviously a good place to look as well. They may have higher points or other costs, but they are pushing a slow to change industry, so the extra cost is simply the price we pay for their willingness to “take a risk.” If you don’t find anyone to lend to you after you’re about half way through your list, start asking for a loan on a post and beam structure with cellulose insulation and leave out the words “straw” and “bale.” After all, nobody gets a loan on a fiberglass insulation house right? Why should you highlight the insulation (assuming post and beam here of course). Just be sure to check for any policy exclusions that could come back to harm you later.

I really encourage you to approach at least a few lenders with the words Straw Bale written proudly on the page. The more they see that, the more likely they are to start lending. Again, they see a trend that could be a niche market and a smart marketing director will jump on it.

Q: I plan on adding a straw bale addition to my house. What considerations do I need to make for this to work?

A: A straw bale addition is not very different from a conventional addition. The biggest difference is the point of attachment of the new to the old. You need to make sure that you have a solid attachment and that the connection is really well flashed to eliminate any risk of water infiltration. Other than that, it’s no big deal.

Q: How do I know if my city will allow straw bale structures to be built? Further, how do I find straw bales? Even further, is there a data base of regions, states, or even countries that produce straw bales?

A: Some of you just couldn’t help but ask more than one question! I would probably be the same.  Anyway, let’s start at the beginning. The best way to find out if bale structures are “allowed” in your city is to ask. The worst thing that can happen is they can say no. If they do say no, be sure to ask under what section of the code are they making that decision. The fact of the matter is that bale structures tend to either meet or exceed almost ever detail of the code if designed and built properly.

Once you know why they are saying no, you can have a clear, factual discussion with the building department and you can provide them with data sheets that support your position. In most cases, an answer of no is more an answer of “I don’t know.” Once again, education is key. Here’s the detail that often gets missed: When educating building officials, do so with respect. All too often people jump on the defensive with inspectors and want to hate them before they walk in the door. This will not serve you well, ever. Help them understand the truth behind the myths they may have heard. Invite them to learn a new technology that is gaining prominence around the globe.

Finding straw is best done by going to the source. Talk to farmers. Go to farm supply stores. Look in farming supply magazines. If you don’t have any of those avenues, widen your search a bit. Chances are there is an agricultural areas within 500 miles of you. That’s a long way to go, I know, but do you think the plywood your neighbor’s house is built of came from a more local source? Probably not.

I wish there was a more accurate database of bale sources. Unfortunately, that is something that has not been successfully created to the best of my knowledge. If I’m wrong, and I HOPE I AM, please correct me here so we can all learn about a great resource we all need. Finally, you can always make your own bales. If you have the crops, al you need is a hand baler (like the old days) or a tractor and baling machine and the time to run it. I baled the straw myself for one of the first structures I built. Were they the best bales I’ve ever used? No, but they worked! Food for thought!

Q: What are the most important aspects of straw bale design to consider when wild fire is an issue?

A: The fact of the matter is that the bale aspects are not the biggest area of concern, the wood frame ones are. Here are the most common details to consider in regards to wild fire:

1.     Gutters filled with debris. Over the course of a year leaves, pine needles and other debris may collect in the gutters of your home.  This isn’t a problem in the wet months (other than potentially clogging your drains, but that doesn’t relate to our topic here), but it can be disastrous in the dry months. A single burning ember flying in on the heat winds of the fire can set your whole house alight if it lands in a pile of dry debris right below your roof line. Keep your gutters clean.

2.     Foundation vents are another place of danger. Very often debris will collect in the vents during the year. If an ember catches the debris on fire, the fire born winds will quickly push the flames into your crawlspace and light your floor beams on fire. From there, I don’t care what your walls are made of, they have no chance.

3.     Decks can collect the same debris and light it up the same way. A bunch of leave bundled under the deck can quickly burst into flames if embers are blown under the structure. The deck then lights up and off goes the house.

4.     Fuel sources around the home like ladder fuels are notorious for setting homes on fire. Be sure to limb up your trees, remove shrubs from underneath them, and keep any grasses mowed and maintained.

Like I said earlier, most home fires are not the result of the straw in your walls, but the conditions around your home. Finally, be sure to protect your bale walls well from fire until they are plastered. The straw itself is not so much at risk, but the chaff hanging off the bales can flare if contacted by flames. If it does, it will chase up the wall and catch the roof framing on fire, which will then collapse into the house. Chance are, your bale walls will be fine in the end, but the house will be heavily damaged in the process.

6 Responses

  1. This construction is new to me.

    I just learned of it recently while browsing an Osooyos lodging site from the Okanagan in B. C.

    Ended up getting an intro on Wikipedia about it. But this site seems more in depth, answering plenty of questions.


  2. A friend of mine recently suggested a problem with strawbale building in north France, the damp clime enabling the bales to harbor mites… does this mean that straw bale building should only be done in a dryer clime?

  3. Hi Stuart. Moisture is the biggest enemy of straw bale homes, but it is not the end all. There are ways to design and live in bale homes in wetter climates. There are some extra steps that need to be taken, but they are not that difficult to implement in reality.

  4. With the advancement and the change in living styles of people, there has been a dramatic change in people’s preferences. With the increased choices, the demands have also increased. Building a home is one of an asset which you probably will build once in a lifetime, as the choices has changed people want to go for things that are in fashion whether they are regarding clothes, cars, furniture, home, shower doors etc.

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