Hi, Do you think a non load bearing strawbale wall construction would be strong enough for a horse stable? Considering a horse may kick, rub, scratch, bump etc off wall. Or is it wise to sheet the first four feet high from ground with plywood? Also how tough is lime plaster when applied to straw, would a horse make a 'mess'/ destroy the wall? All answers appreciated. Thank you
From my experience I think you may struggle a bit.
Given that your horse may well give the wall a knock or two I suspect the lime render will start to get damaged quite quickly. This could be made worse if the bales are not tightly bound. I found lime render to be quite soft, great for letting the building breathe and coping with a bit of movement. But tends to be not as hard wearing as a cement render (this could of course cause you problems if you apply it to straw).
Lining the bottom of the walls with a good thickness of exterior grade ply sounds a good idea if you go with this type of build. It might also be a good idea to ensure the bale walls are sat on a concrete plinth raised above the floor level to try and stop any moisture building up where loose straw might sit against the base of the wall, and for additional robustness when cleaning the stable out.
If anyone has used a bale wall for this type of building and found it has worked, I would be glad to know.
Thank you for your reply. Yes the bales will be well compacted with straps. Ok so the render on the inside may not be suitable. Yes the bales will sit on a plint 2 ft from ground. I'd love to hear from someone who has used this method for animal shelters before with success/failure. Thanks again
@corco2000 - I have built with straw bale (a house, not a barn) and the exterior finish on my exterior walls has been complete for about 1.5 years. Lime plaster, or "render" if you will, in the traditional 3-coat manner, plus an underlying discovery coat, all applied by hand. Total thickness, 1"-1.5" in most places. Actually, I have not yet applied limewash, but otherwise it is complete. I should mention that my walls are also non-loadbearing, as you propose for yours. Mine have 4x4 posts embedded flush with the exterior surface at 4'-6' spacing, supporting a 4x6 equivalent beam.
SherwoodOwl is correct, of course, that no lime plaster has the same strength as concrete stucco, but in my experience it is as hard as you could need. I'll admit I'm not personally familiar with how hard a horse will kick, but casual contact of horses bumping around in the stable would absolutely NOT make a mess of the wall, as you fear. You would need an angry and determined horse to take the wall down. Believe me, if you were to kick my wall with all of your strength, it is your foot that would come away broken, not the plaster. For maximum strength, make sure that you pay maximum attention to detail with the construction. I don't see the need to strap-compress the whole wall, if I am understanding you correctly, but be sure to use sound, well-baled straw. If you chose a good source, they should be tight enough right off of the farm for use; mine were. Use good quality, well-aged lime putty, and wait as long as possible between coats (months, if possible) to allow maximum calcification of all layers. I had really good luck with my own wall: there was hardly a crack to be seen in any of the layers. This will also increase overall strength if you can achieve it.
Having said all that, I still think that using 3/4" plywood or OSB on the bottom 4' of the interior of your wall is an excellent recommendation. It will provide extra protection from the moist environment of the stall (which over the long run might prove a greater threat) AND it will save you a lot of time and money. There is a lot of labor involved in mixing and applying plaster by hand, believe me, and since aesthetics are not a concern, why not?! It should also make it much easier and safer for you to clean the stall - you could even hose down the plywood walls. If you design the barn with the load-bearing posts flush to the inside of the wall, or even proud of it by an inch or less, you could nail the plywood directly to them. If you have windows in the same wall, you might think about that carefully, though, since good straw bale construction usually sets windows flush with the outside surface to minimize the accumulation of rain, and this is most easily achieved by setting the posts flush to the outside as well (assuming that you design your posts to double as rough opening for the window frames).
But I would DEFINITELY advise that you still apply a single coat of plaster on the straw beneath the plywood to better seal it against moisture and insects. That is what I am doing on my interiors behind wherever cabinetry will be attached. Or, you could save time and effort and achieve the same result by stapling a vapor-permeable house wrap across the wall before attaching the plywood. If you go that route, be advised that my own research revealed that cheap house-wrap available at any lumber yard is not best for straw bale construction. You have to identify and call the manufacturer to know, but if you do you will learn that the perm ratings are often much much lower than for the expensive, name brand house wraps.
Also, setting your wall atop a raised curb, as SherwoodOwl mentioned, is always good detail for straw bale construction. But I would advise that you build your curb from treated wood, though, not concrete. Generally speaking, part of a curb's function is to keep your bales removed from touching concrete, since a concrete foundation will wick water up, slowly but surely. That is why residential building codes usually require all wood in contact with a concrete foundation to be treated. A simple and standard curb design that I used is just a double sill of two treated 2x4's set apart to match the outer edges of the bale width, with the space between filled by loose gravel or perlite to create a capillary break. You might even bump up to 4x4s for a little extra height and protection, in anticipation of hosing out the stalls. If you are building the barn from scratch, space your J-bolts or other anchors appropriately for the double sill. If retrofitting an older barn, I guess you will have to go in from above with Redheads or similar screw-in foundation anchors.
I would very much like to hear as well from someone who has actually used bales for this type of building. No doubt they would know about additional considerations that are not occurring to us.
The book "The Straw Bale House" has a wonderful photo of a stable built of straw bale and cordwood construction in France. They never went into detail about which went where or why.
I think if I were to build such a thing, I would go with a thermal break as Issaqueena Oasis suggests but I would use puckboard to line the bottom part of the stall. This is the stuff they use around the outside of ice rinks for hockey players to bounce off. It IS a plastic I think, so shouldn't be snugged up to the bales or you might encourage problems with moisture, but it's easy to keep clean, almost indestructible, comparable in size (4x8) and price to plywood, which will degrade and absorb odors of urine, and sometimes get chewed on to neither the plywood's nor the horse's benefit. I have seen barns that were built with love and care looking like great monstrous termites have been at them and it's really sad.
For my horses, I just have a windbreak of big straw bales two high and shaped like adjoining U's facing south (UU but the interior wall is shared, each U is about 3 bales wide.). Sometimes one horse will feel as though it wants to have the shelter to itself so although mostly all three are in one section, options are a good thing. It's in the middle of the field so no matter what direction the wind comes from (except straight down!) they can get out of it. They also have some treed areas, but they only retreat to those on the occassional horrible days of driving rain/wind or wind and sleet. If I had managed to put a roof on the bales then they would be blissful... They go through the Saskatchewan winters fat and happy with just good alfalfa mix hay and the bales and trees for shelter. So your horses will be blessed with whatever you provide.
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