Stucco over straw bale patio wall
Okay, new to the forum so be gentle. Been a subscriber since the inception just never got around to utilizing the brains around here.
Thinking about building an outdoor patio wall out of straw bales and covering with stucco. I’ve done a lot of projects in my long life, but never have worked with stucco for some reason. Can’t find anything at the local library and my back issues of FB don’t seem to have anything specific to just stucco for exterior walls like I’m thinking about.
How do you calculate how much stucco you’ll need given x for sq. footage? There’s something about three coats needed but nothing much in thickness or composition of each coat. Is it better to buy pre-mixed or go get a truck of sand and mix up with portland cement? How do you color it to match existing stucco house walls?
Would I be better off using cinder block instead of bales? If so, why? Seems like the cost far outweighs the difficulties no?
Thanks all for any and all input!
The Coconut Man
Replies
I know nothing about stucco over straw bales. Sounds interesting but I would think that the movement of the bales could cause big cracks in the stucco. (dont know, just guessing)
Re. stucco, I have only done a little but like mixing the scratch coat myself with sand and cement. (either hydrated cement or cement and lime) I dont know if you can buy pre-mixed scratch coat which is just cement.
For the finish coat, you need to either buy several different sands (yellow bar, brown bar, whatever else the suppliers have) and sample with different colors of cement to see what color works well. You can also buy dye and put dye in it to color it as well. Once you find the magic potion, you need to replicate it exactly or you are in trouble.
The easier way is to go to the local masonry supplier and see what they have in pre-mixed finish coat stucco's and see if they have a color that would match your house close enough to make it work. That way there is no mixing and you can get all the info you need from them on coverage, etc.
Good luck
I googles "straw bale and stucco" and came up with several books on the subject.
I dont personally have any experience with it but when I lived down in Austin TX I knew of a guy that did a house with straw and stucco, worked well for him, it was about 6 or 7 years old and no problems thus far.
Doug
I think one of the keys is to properly "frame" the wall -- there must be wood (or, I suppose, metal) members inside to hold the bales tightly together.
If your view never changes you're following the wrong leader
Yea, there must be something in there for structual purposes.
I think the idea is pretty neat, I'd probably never do anything like that but if I was in Arizona I might re-think that.
Doug
Doug, Actually there was nothing but bales for load bearing in the "Nebraska" house of historical use. Hip roofs spread the load out evenly over all the walls. Single story construction only.
They can't get your Goat if you don't tell them where it is hidden.
I have helped build several straw bale homes. The bales must be elevated on a foundation. You just lay the bales on the foundation, jammed tightly together. The next layer is staggered, like in a brick wall. Short lengths of rebar are pounded down through two layers of bales. When the wall is at it's appropriate height, it should have rebar holding the whole thing together.
The wall is then stitched together with baling twine or wire, using a baling needle, a steel rod sharpened on one end and with a hole in the
pointed end. A handle is made by bending the other end 90 degrees.Stuff loose straw into the gaps between the bales. We didn't use stucco for the plaster, preferring to use clay plasters,
made on site, if clay soil is available. It has the advantage of moisture permeability over stucco, and isn't so stiff. I don't know much about earthquake proofing a stucco or clay plaster house. good luck with your remodel.
Coconut,
Do some research on the web.
One issue with straw bale construction is moisture entering the bales and causing rot.
Stucco is not a good moisture barrier.
Not having a roof over the wall would compound the problem.
Stucco is the usual covering.
If your view never changes you're following the wrong leader
Dan, Yep, and so is the use of a moisture barrier and when the bale is elevated off the moist ground and a roof is placed over the structure. Op is building a garden wall. Sorry but in his case he would be better off with cinder/concrete block.
They can't get your Goat if you don't tell them where it is hidden.
And climate is a big factor. Didn't make note of the OP's climate, but you need something drier than Seattle at least.
If your view never changes you're following the wrong leader
I'm in a climate of 10-12 inches rain a year with very hot dry summers interior central coast california. I've got two books coming on building houses, which would have the prerequiste roof overhead for protection, but nothing so far on outside walls.
So, clay over stucco so far. I know I need to stitch everything together and general construction technique of the straw bales along with framing where the entry door and "windows" will be. Tightly stitched poultry netting to anchor the plaster whatever it will be. Felt under the netting? How about where the bales meet the foundation? I plan on pouring a two foot wide by one foot deep footing complete with rebar for support. Should I plan on framing a four inch "step" so the bales don't sit at ground level? (stupid question I know, but......). Total wall length is 80 feet long by six feet high broken into two sections.
Thanks for all the input....keep 'em coming!!!!!!
Mark
The normal test is 21% for 2 weeks or longer for the bales to start to break down.
The normal idea is to forego the moisture barrier and choose the right kind of stucco that has low permeability. the plaster and stucco skin is where the magic is at, plus the right outer paint to reduce perm rates.
the test for nw are running at 40mm cement/sand stucco. the more lime, the higher the permeability. there's some studies in portland on linseed oil coatings, but the results are inconclusive.
But, all that predisposes you are off the ground. In load bearing, you have the wood plate and in P&B the bales are infill - but still up.
the block surroundings are working well, and some folks are having good luck with rastra.
but, no barrier layers between the bale and the stucco....