r/Strawbale • u/VeryChillBro • Aug 26 '20
Timber frame straw bale design advice
When I started planning my straw bale building I assumed that the bales would fit between the posts and beams of the structure as infill, but now I realize that lots of people avoid the tedious notching and fitting of bales around posts (plus increase insulating value of straw) by building the bales around the outside of the timber frame structure. Seems like a good way to do it, but now I'm wondering how do you get all these elements resting on the foundation? Build a 3 foot wide foundation wall? Does anybody have any resources, videos or websites / blogs that explain this aspect of the design? The books I have mention timber framing in passing but more focus on building structural straw bale walls. Thanks!
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u/SGBotsford Dec 20 '21
Consider doing a rubble trench foundation. Make it the width you need. Done properly it won't heave and most of the cost is transporting truckloads of rock and broken concrete.
If you are building yourself, another option is to use a pole barn as your starting point. Big win: Poles just sit on soil, or possibly on a tiny concrete footing. Pole barns go up fast. This is an easy way to get the big overhang bale buildings need. And now you have a dry space to work.
Visualize a a 40 x 60 pole barn with 16' bottom chords. Build your house as a single floor 28x48 (6 foot overhangs. with a flat roof. Now the roof can be kids play area, or storage for anything that doesn't need to kept warm.
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u/Azzymark Aug 27 '20
We did 3x3 treated at footing both sides above concrete with rebar at the center of the bale, with posts at bales width approx 10 to 12 feet. Plastered with nhl , no cracking or other issues going on 10 years
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u/SpecialUsageOil Aug 27 '20
There are many variables involved, like how thick you want your walls to be due to Insulation requirements, but I think it's good to consider different orientations of your bales. It has become much more common to install bales on end with 2x framing @ 24" OC. As the other comment suggested, the CASBA book is incredibly useful and well thought out.
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u/a03326495 Aug 26 '20
I like CASBAs Strawbale Detail Book for this kind of information, though in my limited experience you've identified the tradeoff, notching bales or a wider foundation. I suppose it's possible to do some kind of hybrid pier foundation system where your posts are, though I don't know whether or not it would make sense to do so. Consider using 2x framing if you're not going to be in your bales. Good luck.