Concrete-Free Slab On Grade Foundations with Josh Salinger | Passive House Live

Join Josh Salinger, founder and principal of Birdsmouth Design-Build, as he explains how to design and construct a high performance floating plywood slab on grade assembly successfully. His presentation covered the science behind why this works, how it meets code and practical methods of incorporating this into your projects.
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[@dalehulst4128]

Well done; thanks for the great details (drawn and photos) and lessons learned! Videos like this help make low embodied carbon doable; thank you!

[@terrylutke]

Material cost for the 4 layers of sheet material will be $6 - $7 p/sf. Material cost for 4" Concrete with 4" EPS at about $5-$6 p/sf (dependent on reinforcement req). Big DIY advantage goes to the plywood/EPS system; consider using a Permanent Wood Foundation to eliminate 100% of concrete. PWF also DIY friendly. Perhaps an insulated concrete slab would prove advantageous by adding heat-sink value in colder climates.

[@charliebowden2455]

How is the foundation holding up? Have u had the house tested for mold since the move in? How did it turn out? Really would like to try this out. Have you built anymore houses like this? What did they think of it?

[@jimknoke733]

How much compacting do you need to do of the earth and then of the gravel?

[@scottwebber652]

Any possibilities on a garage floor application w/o a concrete slab?

[@SpaghettiMarinarable]

Great into to a new technique! Prefab wall would make not having a deck to frame on a non-issue. Have you considered SIPs or off-site built walls?

[@microcolonel]

I've been thinking about combining this with permanent wood foundations for concrete-free basements. :+ )

[@ihulkoutftw]

How much give would the floors have? Would things shake or rattle as you walk? Or is it subtle enough that you wouldn’t notice?

[@jimknoke733]

Does this have advantages over a Frost Protected Shallow Foundation? Could we use a shallow grade beam around a concrete-less slab?

[@jacobdurant9117]

Would you be able to do this with post frame?

[@Thelastmistake]

How is the insulation in the garage? How many psi so a car won't compress it

[@jimknoke733]

Do you need to dig down to solid earth before placing the gravel?

[@2point..0]

@Josh Salinger Hello I was wondering if I could have a conversation with you on Concrete Slab, with radiant floor heating with rigid foam and plastic barrier, our building also might be out of Order too??? We live in New England and We being my Wife and I are designing and going to be building an OFF-grid home. I am trying to source out the most efficient and economical and strong I.C.F for our Foundation and I am trying to reach out to people that actually have used them with good results... When you contact a manufacture they all down play their competitors in the worst way to survive !!! As I have built before and this will be my first ever use of I.C.F's I want to take a consensus of Real Users to be honest!!! Liked#52!!!

[@jacobdurant9117]

Are you able to do radiant flooring with this?

[@HistoricHomePlans]

I had the same thought. I wonder about the possibility of using Warmboard for the upper plywood layer.