www.inhabitat.com

I just received an email in which a man asked about using bales below grade, as in an earth-bermed house. He wants to use bales due to their high insulative value, but is concerned about the effects of moisture on the bales. I too would be concerned about the moisture. We are trying to figure out a way to make it work as it would be a great marriage for sure! (more…)

If you are like me, you want to keep a large assortment of screws around the house for all kinds of uses. Keeping them organized can become more of a challenge than not having screws though if you don’t have a solid plan and place to store them all. I tried the expensive “screw bags” for a while but didn’t like them. I find the easiest and least expensive/most enjoyable way to store a bunch of screws is in small glass (or plastic if you prefer) containers with screw on lids. Simply label the glass with what’s inside (tape works well for this and then screw the lids to the bottom of a shelf. Use two screws so the lid won’t turn when you twist the jar. The cool thing is that you can still use the shelf since the jars are suspended.  You can take the jars to the site of the work and return them to the shelf when you are done. It’s super easy and organized. It’s the most enjoyable way to store screws (and other items) because you get to eat the food that comes in the jars! The more screw sizes you have, the more you need to snack on that favorite food item. I hope your perfect jar size isn’t mayonnaise as that might be a bit sickening.

It may seem like a simple part of the overall construction process, but getting the foundation right is incredibly important. The biggest reason for this is that any mistakes you make in the foundation will only get worse as you go up. It’s known as compounding defects and it means that mistakes grow. Here’s an example: You notice that your slab foundation is 3/4” out of square when you start framing. It’s also 1/2” out of level across the total building. You figure, “well, I can handle that. I’ll just adjust it in the framing.” As you complete the framing, you get up to the roof and notice that the building is now 1” out of square and 3/4” out of level. Bummer, but you figure you can capture it in the roof framing. By the time you metal roof shows up, the square panels don’t fit on your out of square roof and you have “to make it work.” In the end, everyone and your grandmother can see that the roof is out of square and the simple mistake in your foundation has ruined the look of the house. I’ve actually seen this happen to someone. It was a “simple” mistake and it just got worse and worse as he went up in the construction process.

Here’s another reason that your foundation deserves the highest focus and attention to detail: your entire house sits on top of it! If you skimp here and something fails, it’s not an easy fix. Is it worth the extra few dollars to add a bit more rebar to the slab? Yes. Ensuring that the foundation is built to the very best standards possible is very much worth it. Here are some simple things to look out for when building your foundation and/or slab.

1. Make sure that the rebar is the right size and is laid out in the right spacing for your soil/geological conditions. A typical residential house in the United States uses #4 rebar in the foundation walls and #3 in the slab on an 18”x18” grid pattern. The layout for the foundation rebar depends on the size of foundation wall and the local codes.
2. Do not allow any rebar to “daylight” or even come close. No rebar should end or be placed within 4” of the edge of the concrete. Rebar closer than that can draw moisture from the outside and rust. That rust will creep down the rebar and, over time, render the entire rebar system useless.
3. Pay extra attention to the layout of your foundation and slab. Make sure that the corners are square and level. The closer to perfect you are, the better, but in no case should you be more than 1/4” out of square or level for a roughly 2000 SF house. Use a laser level if you have one or the best standby of all time: a water level. It’s the cheapest level you’ll ever buy. It’s basically some clear plastic tubing, water, and a little red food coloring to help you see the level lines better. You can even use this set by yourself.
4. Wait until the water has evaporated off of the top of the slab before you start finish troweling. If you press that water back into the surface of the concrete, it will weaken it. Allow it to cast off the water it doesn’t “want” and then get on it for the finish work.
5. If you plan to acid stain your concrete, don’t over finish the surface. If you polish the surface too much, you will seal it beyond what the acid stain can react with. You can definitely get the surface smooth, don’t get me wrong, the key is not to power trowel the heck out of the slab.
6. Use a stepped foundation when applicable to minimize concrete use. If you have a sloped site, step the foundation up or down the hillside to work with the topography. Be sure to measure the steps and keep them in line with the bale courses so you can step the bales too down the road if that works with your design. This won’t apply in all cases, but if it does, it’s great to get it right when stepping the foundation to keep your bale work easy.
7. Spend some extra time around your foundation bolts when finishing the slab. Many people don’t put a lot of attention here because they figure “it will be buried in the wall so who cares if it looks good.” This is one way that mistakes compound. When you add your 4×4 toe ups to a series of foundation bolts sticking out of poorly finished concrete, you will quickly find that the 4×4’s won’t sit flat. The thick 4×4’s won’t bend like a 2×4 to fit flat either, so you will be left with a toe up that’s up in the air in some spots and flat in others. This not only allows for air gaps through which bugs can also travel, but also messes up the framing before you even start it. Finish those areas well and you will be happy you did.
8. Use Wedge Bolts or other “after cure” anchors for the interior toe ups. By adding the interior anchor bolts after the concrete has been finished you can get a better finish on the concrete (not only for the bolts as described in #7, but also for your floor which will come very close to the anchor bolt locations). Using the drill in bolts also makes the layout and installation of the interior toe up a lot easier and more accurate.
9. Be sure to vibrate your form boards to eliminate “honeycombing” of the concrete. This not only improves the strength of the wall, but increases the beauty. This can be as simple as pounding a hammer against the form boards while the concrete is still wet. Do this BEFORE you finish the surface as the vibration can make the surface of the concrete drop a bit.
10. Use adequate bracing for your pours. There is nothing worse than having a form board blow out during a pour. It means more concrete will be used and your nice straight line will be shot. Use lots of diagonal braces to support the forms during the pour.

When framing your roof, don’t waste time lining up your rafter tails. Let them run wild and cut them all at once when the frame is complete.  Decide where you want the ends of the rafters to be and then snap a chalk line from one end of the house to the other. Use a jig made from scrap plywood to mark the plumb cuts on the rafter tail sides (a top piece sits on the top of the rafter and another piece lays out the plumb cut line for the rafter tail). Mark the line and cut the tail with a skill saw. Move your way down the wall until you reach the end. This ensures a perfectly straight fascia line, even if your initial framing job was less than perfectly straight!

Have you ever needed to drill a hole in the ceiling and found yourself tasting plaster for two days? You’re not alone. Here’s a simple trick I learned years ago. Take a disposable pie tin and drill a small hole in it, just big enough to allow the drill bit to stick through and rotate freely. Now when you drill the hole, the pan will catch all of the droppings. Brilliant!

Everyone has heard the phrase “Good Hat and Good Boots” in relation to building a house. Well, maybe not everyone, but I bet a lot of you have. It means pay attention to your roof and your foundation. These two areas are very important; however, because they are relatively boring in the grand scheme of things, they often get less attention than they should. People building a house often like to spend time thinking about their amazing new kitchen or their fancy master suite, not their roof and how it’s built.

The catch is that how your roof is built is perhaps one of the most important details in the entire project. Why? There are several reasons. Here are a few.

1. Insulation Value. Everyone talks about how amazing straw bale houses are for creating a super insulated home. That’s true, but only as true as the roof is insulated. I think it was grammar school where I learned that heat rises.  That law of physics is still true today and if your roof is not properly insulated, that law will ruin your super insulated home. There’s simply no point in building a house with R-40+ walls and an R-30 (code for vaulted ceilings) roof. Over insulate whenever you can. I find that two layers of R-21 insulation fit perfectly into a cavity created by 2×12 framing or 11 7/8” engineered lumber. Those are the two most common rafter sizes in vaults, so there’s no reason you should not have at least an R-42 roof. If you are using trusses, the insulation can be even higher.
2. Strength. As I mentioned above, the most common rafter size these days is 2×12 framing or 11 7/8” engineered lumber (BCIs or TJIs). Don’t skimp on design or implementation here. I remember reading an article several years ago about a man who was killed when his “straw bale house collapsed” (according to the newspaper). When I read further, I saw that the straw bales had, in fact, not collapsed nor had they caused any damage to the house. Instead, a large snow load had caused his under-sized rafters to collapse under the weight of the wet snow. A tragedy for sure, and one that could have been avoided if the rafters were sized properly.
3. Protection. The roof obviously does a great job of protecting you during weather; however, the protection I’m talking about is more about proper passive heating and cooling design. Be sure to take the time to properly design the roof overhang to provide the proper shading and solar gain for your latitude. Every site is different as is every design (I hope), so it’s really important to take in account all of the factors you have on hand. For example, site slope, latitude, potential shading from neighboring structures or landscapes, standard weather patterns for the area, and so on. The more data you can amass, the better.
4. Slope. The slope of the roof can impact many aspects of the home. The steeper the roof slope the quicker an overhang will encroach on window views as it is extended, the faster water and snow will slide off of the structure, and the less practical roof repairs will become. If the roof slope is too low, water and snow will build up and won’t drain away quickly. This can cause leaks and damage may occur to the house. A medium sloped roof may be the perfect choice not only for the above details, but also for the inclusion of solar panels to power the house and heat the water. As always, the exact slope will depend on the design and the natural impacts of the site.
5. Overall Design. The more complicated your roof design, the more expensive it will be to build. It’s hard enough to build a good roof with even the simplest design. If you add lots of valleys and hips (intersections of other roof lines, etc…) things get complicated quickly. After all, the roof is built up in the air. That’s not easy to do. Then once framed, the complications continue when t comes time to flash and waterproof it. Finally, the installation of the finish material itself is also complicated. What you use for the finish material can also have a large impact on the functionality of the roof.  Standard asphalt shingles don’t make a good surface for water collection, metal roofing (although great for water collection) can reflect the sun and heat into neighbor’s properties, natural materials like slate have pros and cons as do the recycled “fake” counterparts. Check out all the details before you make a decision. Also, don’t look only at sticker price. Consider the lifecycle cost of the material. If a metal roof will last you 50-150 years, will provide water collection, and will reflect heat away from the home, then perhaps the added sticker costs are worth it.

This is just a sampling of the things I encourage you to consider when thinking about and/or designing your roof. There may be other site-specific things I have not listed and those are always important to pay attention to.

There’s no question that your local climate will have a large affect on your home, whether it be a bale home or a home made of concrete block. In fact, the climate is often a driving force in people’s decision to build with bales. I’m sure you’ve heard people talk about how hot their climate is or how cold it is and how if they only had a more efficient home, they could better stand the extremes. Unfortunately, some people decide to build a straw bale home before they consider the potential affects that their climate could have on it until its too late. It’s important to know what might happen to your home before you build it because there may be steps you can take to minimize those affects if you plan ahead.

Below are some of the affects that climate has on a bale home. Some of these may seem obvious while others may not. I’m sure I’ve missed some, so feel free to add your own in he comments section.

(more…)

Dun, dun dun…… Can you feel the excitement? I just got back from working on a project in Portugal and the plaster machine was one of the coolest I’ve seen. This monster mixed up to 1 1/2 bags of lime plaster at a time (35 kg bags). The capacity was not what made the machine exciting as some of the mortar mixers I use here in the States will mix twice that capacity at once. What was cool was everything that the machine was able to accomplish. Here’s a run down.
(more…)

It is so important to stop the flow of air through your walls. This is not the same thing as “breathing walls” which we straw balers like to talk about as a good thing. That is entirely different. In a breathing wall, the concept is that air, pressurized from the interior of the house will slowly make it’s way through the walls, starting with the interior plaster, moving through the bales and finally escaping through the exterior plaster. That’s all good because the interior plaster removes the majority of the moisture from the air and releases it slowly, back into the room, and through into the bales. It does that release in a slow and controlled fashion, so the system stays in balance. More on this process at another time. This blog post is about something entirely different: stopping moisture laden air from moving directly from the interior, conditioned space, into the bales.

(more…)

If you live in a coastal area or mountain region, you probably have more experience with big wind gusts than someone living in a quiet little valley (except for those screamers that whip down the valley from time to time). The point is that wind is different wherever you go and building codes reflect those differences. Some areas in the United States, like Florida, Texas, and other Southern Coastal states, have to design their homes to withstand hurricane force winds while areas in Tornado Alley have to build their homes to handle twisters.

This morning I was looking through the internet in search of facts about straw bale construction and high winds and I was shocked to see that the hard data is far and few in between. This seems to be an area in which some studies have been done, with promising results, yet little follow up and publications exist. I hope that I am wrong with this assessment and that, in fact, there are studies and papers out there that I am missing. To that end, if you have any leads I should follow up on or if you know of specific resources in regards to high wind/straw bale studies, please let me know. The following is what I was able to discover and, like I said, it is very promising.

(more…)

Okay, so that’s a bit of an exaggeration, but we sure did get a lot accomplished at the load bearing workshop in Crestone, Colorado.  Consider that when we got to the site, there was a rubble trench foundation with an 8″ concrete cap and nothing else. When we left, there was a building with windows, roof trusses and plastered walls. That’s pretty cool! It’s amazing what a group of people can accomplish in a short time, especially when you consider that they were learning the whole time too. It’s not like this was a group of professional builders, after all.

We had our challenges, don’t get me wrong, but in the end the desire to help build a wonderful couple a home won out over every little speed bump and hiccup. This truly was an example of community coming together to build a home. Several of the workshop participants lived near by and were able to help out immensely by bringing in tools, materials, and even extra generators and compressors (the compressor actually saved the day). Thanks Jenna, Skip and Zach!!!

Then there were the locals from Crestone who were not even part of the workshop, but who helped out by sharing their materials, connections, and know how before I even showed up for the class (and during as well). Thanks Paul and Heather!

(more…)

That’s a question that I have been asked potentially thousands of times over the years teaching workshops. I like that people ask the question, actually, because it shows me that they are paying attention to the details and wanting to make the house the best it can be. The answer is usually “yes” but has been “no” a few times. When it comes to stuffing loose straw in the wall, one might think it’s easy: just grab whatever loose straw is around you and shove it into the hole that needs to be filled. Well, nope. Like so many things in life it’s a little more detailed than how it first appears.

The first thing to keep in mind is that you want to use long straw, not short and stubby pieces. Certainly do not use material that has been cut from the wall either by a chainsaw or weed whacker. That straw is way too short and will not create a solid patch.

Second, be sure to twist the straw into a rope. In fact, I prefer to twist the straw into a rope and then fold that rope in half before I place it in the wall. This helps tie it all together and keep it tight in the gap it’s filling. Spaces that can’t be filled in this way because they are too small can be filled with looser straw packed in tight around these ropes. Be sure to use long straw!

A third detail is when to use a clay slip. Most gaps can be stuffed with dry straw as long as it is well packed as described above. Some bigger holes may require a clay slip to be applied to the patch straw to help it stick, literally, in place. The slip also cuts down on potential burning of the patch should a fire spread across the wall. Of course, that’s a bummer no matter what, but it’s still important to build to the best standards you can.

Once thing to keep in mind is that stuffing the gaps between the bales, if any, is easiest done while stacking the bales. Stuff some material as described above in between the bales and pack it in tight. This keeps the stuffing in place when weed whacking and helps to tighten up the wall as you build. Waiting until after the walls are up makes the stuffing process slower and more labor intensive overall.

Over the years through conversations and books I have heard that it is fine to plaster directly onto straw bales without the use of any type of mesh reinforcement as long as the mix is lime or earth based. I recently did somewhat of a test on this by plastering a house that had both: bales covered with welded wire mesh and bales left without mesh. I know I will catch some flack for this, but to those of us involved in the “test” the answer was clear. Plastering bale walls that are covered with welded wire mesh is way better than an unmeshed wall.

Can it be done without mesh? Yes. Is it better than walls covered with mesh? No. In fact, the walls that were left without mesh had some major problems that needed to be dealt with, and sometimes the only fix was…you guessed it, to add mesh! I understand that some people don’t like the idea of using metal mesh on their house. I know that some want to keep with a more environmentally friendly material like jute (see recent blog post about why this is a bad idea!). Others don’t like being encased in a metal mesh “cage.” I can’t change your mind on those things (perhaps), but I can at least point out that a house built to last is more environmentally friendly, safer, and more economical than one built on the cheap.

I’ve listed the biggest problems with plastering directly on the bales here.

1. Here’s mud in your eye! When plastering on walls that have no mesh, the straw is likely to flick the plaster back at you as you apply it to the wall. Not a big deal if it is “mud” in your eye, but it is more of a big deal if you are using lime plaster (which in my mind is almost always the best choice) as lime can and will burn your eyes. In fact, of all the warnings on bags of lime, the most prominent are those warning of direct eye contact. Yes, glass are a cheap fix to this problem, but it is something that is easily fixed by using mesh.
2. Stuffing. It’s pretty common to need to stuff areas of a wall with loose straw between bales or against a post. Not everyone is perfect with a chainsaw or with measuring and retying a bale. As a result, loose stuffing is often used to pack those gaps. To begin with, it is very important that these gaps be filled with long straw and packed very tightly in place. In fact, a clay slip applied to the packing can be a good idea too. Even further, some folks choose to use cob in the gaps (if they are big enough to warrant doing so) but this brings up other issues with bonding between materials like cob and lime plaster. That’s for another blog post another day. Anyway, back to the stuffing. With no mesh to hold the looser material in place, it can fall out of the wall under the weight of the plaster. Obviously, not good.
3. Loose straw doesn’t hold plaster. Just like the stuffing issue, the uncut edges of bales can be hard to plaster. In other words, if there is a part of the bale that has long straw hanging out of it, the plaster will stick to the straw and then potentially fall off the wall. It also tends to hold the straw away from the solid surface of the bale meaning that the connection between the plaster and the straw is connected to the loose ends only, not the main bale.
4. Smooth bales are hard to plaster. On each bale, there are two edges: a cut edge and a folded edge. The folded edge can be very slick, depending on the type of straw used, and as such, it is hard to key the plaster into it. This means that even plaster that appears to be sticking well can ultimately fail if it is not well anchored to the bales.
5. No reinforcement. Plaster without reinforcement, is not as good as plaster with reinforcement, it’s just a physical reality. Yes, the plaster can get that reinforcement from the bales if properly keyed in; however, as mentioned above, that keying is not as easy to accomplish without mesh. By adding mesh, you are adding tensile strength to the plaster. Like concrete, plaster is very strong under compressive loads (pushing it together) but weak under tensile stress (pulling it apart). The mesh give you extra strenght in the tensile stress situations meaning less cracks and overall better plaster.

So I don’t suggest that everyone who says you can plaster directly on the bale is wrong. In fact, I agree that it can be done; however, I believe that it is not as good of an installation as can be accomplished with mesh. I prefer to shoot for the best installation possible. To me, that means mesh is best.

You likely hear people talk about protecting your walls from rain during construction. Surely this sounds like a good idea and it is indeed something I agree with…to some extent. To me, the most important aspect of protecting your walls is to make sure that no water makes its way onto the top of the bales. Of course, if it is going to rain for a long period, then protecting the walls from rain on all sides is a good idea, but if it’s an occasional rain shower then the tops are truly all that matter.

Consider what you do before plastering the walls. Yes, you spray them with a hose to get them wet. They can handle some water on the sides, it’s the nature of the material. If you look at a straw bale, you’ll notice that it has different sides: a cut edge and a folded edge. The cut edge does a great job of draining water away and the folded edge does as well. The problem comes when water is dropped down into the top of the bale because it can then settle into the middle of the bale from which it has a hard time draining (unless laid on edge to drain which you can’t do once the house is under construction).

As your course go up, be sure to cover their tops, especially at the end of the day if rain is in the forecast. I would not suggest that you bale with the wall covered the way it is in the picture. This was at the end of the day. If you are experiencing a lot of rain and your overhangs are not adequately protecting your walls during construction, then hang tarps from the eaves (or even better…build better overhangs!). In most cases, you should be able to build without added protection and should simply protect the walls as shown at the end of the day. There’s nothing quite like waking up at 3am to a massive rain storm and saying to yourself “I really wish I had covered the bales. I hope they’ll be okay.”

I like to stay open to new ideas and techniques. I think it is really important as no single person can possibly have all the right answers, all the time. I am not exception to this rule, so I like to hear what ideas other people have and I like to try the ideas that sound and/or look promising. That was the case with the idea to use jute netting on a recent woodshop we built in Ontario during a workshop. The host was very interested in using the netting as a means to lower his costs and use a natural material. I agreed with the idea after researching it a bit and learning that it had been used to supposed success on other projects.

Now you probably know by now that I am a huge fan of using welded wire mesh on my structures for many reasons, so opting for the jute netting in place of the mesh was a big step for me. It’s not like I went to therapy to get over making the decision, but it was, nonetheless, a stretch of my comfort zone!

The title of this entry mentions the word “why” so I will get to that now. I will not use use jute again in my structures, unless for some absolute necessity, because:

1. There is absolutely no “real” strength in the material. When I pulled on sections of the jute to see if I could tighten it across the face of the bales, it ripped. I’m strong, but not that strong! If I pull on mesh all that happens is I hurt my hand.
2. The material is woven. This, once again, means there is no strength in the material; this time for shear resistance. If you pull the material one way, the weave opens up. This is great for stuffing because you can literally open the jute up as wide as you want, right in the middle of the sheet; however, it makes for a weak material to hold the bales in place or provide shear strength.
3. It’s bulky when not pulled super tight. If the material is not pulled really tightly apart, the ropes of the weave lie close to each other, creating a sheet of jute rather than a net of it. This sheet would keep any plaster attached to it separate from the bales. Not a good way to key the plaster into the straw for sure. As I mentioned in reason #1, you can’t pull the material that tight because it rips if you do.
4. Sewing the jute to the walls only makes the loose areas stand out more. I had hoped that the stretchy material would tighten to the bales once sewn but this was not as I had hoped. It did tighten up directly under the sewing, but the sewn area did not lend any strength to immediate adjacent areas like welded mesh does.

I know some people will say that jute works and they will mention that they have used it themselves with success. Great! I am glad it worked for you. This is a material I am clear about for my own projects and those that I teach on. I will not use it again. Welded wire mesh is superior for several reasons and I am completely sure that the mesh is the best way to go.

I am not a huge fan of using battens to strengthen my bale walls. I much prefer to use welded wire mesh as I believe it not only provides a stronger hold, but also a superior “all around” structure for the walls. There are, however, specific cases where battens are needed and if you find yourself in one of those situations, this is the system I suggest you use.

One of the major problems with battens is that they sit proud of the surface of the bale wall so plastering around them is difficult. For starters, it’s all but impossible to get plaster behind the batten so to fully seal the wall in the scratch coat application. This leave the wall susceptible to air infiltration later on. Secondly, the battens, once covered with plaster, become a weak spot in the finish because the plaster is obviously thinner over the top of them and it also does not have as strong of a key as it does in the bales themselves. So how to fix this issue?

Use an angled batten. The battens that we used on a recent workshop build are shown here. Notice the profile is such that the triangular shape helps to pull the face of the batten flush with the face of the bale walls. This still leaves plenty of surface area to tie them to the walls (inside and out) and it also leaves a flat surface to be covered with roofing felt (all wood should be covered with felt if plaster is to go over it). It may take a little effort to work the battens into the bales so to get them flush with the wall, but it is well worth it and your plastering will be significantly easier as a result.

The last trick to an easy installation was given to me by John, a recent workshop participant. He created “the ultimate batten needle” which I have shown here as well. It is a simple wood jig designed to automatically space two needles to fit around the battens with ease. Plunge the batten needle through the bales (one needle on either side of the batten) and then have a friend on the outside attach the twine to both needles. As you pull the needles back through the wall, the helper inserts their batten in between the twine and their side of the wall which is then pulled tight to the wall. Once you have the twines back on your side, tie them off in a tight miller’s knot. Simple and efficient. Thanks for the great jig John!!!

When most people think of niche in straw bale walls, they picture the flat bottom, arched top nook with a statue or flower pot in it. I love that look myself and have made many of them. Recently, I had a workshop host who wanted something sweeter in their bedroom. The heart niche was the result of that idea. Made in the same steps as a typical niche, there’s nothing terribly different about it other than the shape.

What I want you to gather from this blog entry is that the only limitation to the niche you install in your project is your imagination. If you can think about it, you can most likely create it. That’s a great advantage of working with straw and plaster. So have it! Have fun and create beautiful things!

One thing that I have done in the past which can be fun is to combine a truth window with the niche. As an example, the heart niche here would have a glass back to it which would reveal the magic of the bale construction. It’s a cool way to bring some depth to any niche. Throw a couple built in shelves into the assembly and now you’ve got a useful and beautiful addition to the home.

Remember: Have Fun With It!

There may be no more beautiful look than a timber frame house wrapped with straw bales and plaster. It’s as if the two were made for each other. Although the look is fantastic, the actuality of creating that look can be a bit troublesome if you don’t approach the project from the right angles. There are most definitely some differences in techniques when it comes to creating a straw bale wrap on a timber frame house. Get it wrong and the look will still be there, you will just end up more tired and frustrated than you need to be!

I can tell you that the techniques you need to include are simple and that with proper execution, you can have the look you want. What I can’t tell you, via a blog post or email, is exactly how to implement the techniques. That’s because seeing it and doing it in person is much easier than describing it in words. That said, here it goes…
(more…)

I was recently asked about using different finishes for straw bale walls on the interior. I’m very often asked about using different exterior finishes, but not as often does the topic of interior wall finish come up. Of course, the type, texture and color of plaster is always in question, but more rare is a discussion about using metal panels as a wall finish, or perhaps drywall or even tile.

The answer is that yes, these things can be done; however, “is the amount of extra labor worth it to you?” may be the appropriate question to ask yourself. Keep in mind that straw bale is an organic building material. Where this is most obvious is around curves by windows and doors. At every workshop I teach, people ask me about making a template to measure each window well with to make sure all of the window curves look the same throughout the house. Possible? Sure. Plausible? Not really. The fact of the matter is that each curve will be slightly different. That’s part of the beauty of building with straw bales. So now consider how you might finish an 18″ deep window well that has a natural, undulating curve to it, slightly different on each side of the window, while using metal panels. How do you attach them to the house? How do you adjust for the irregular shapes within the window well?

You can see where the difficulty comes in. The same is true for any material you use that is rigid and “unforgiving” to uneven sub straights. The key is to provide backing that fully supports the material in mind to ITS specifications. This means that you may have to insert framing to support the material every 24″ on center, or provide for nailing on a specific pattern. You’ll need to weigh the pros and cons of each finish you choose and see just what is worth your efforts.

I have seen corrugated metal roofing used in shower stalls and in straw bale barns to great success; however, would I do an entire room with that material? Probably not. I think for specific spaces that require something like this, it is worth it. If you want your walls to look like drywall on the inside, then I suggest you build with drywall, and forgo the straw bale infill, or at least create a hybrid installation system that will eliminate all of the “extra” framing to be notched in to the bales, post stacking.

Several of you have, over the years, written to me about using straw bales that are wrapped in plastic. The suggested benefits of this have ranged from no need for additional vapor barrier, to ease of stacking, to being able to mortar the blocks together. Although this would seem like a good idea at initial glance, I don’t like the concept. Here’s my thinking:

Photo Credit: www.wajking.com.au (more…)