Insulated floor- (foam board sandwich?)

[Jonroth]

I am thinking of building an insulated floor by sandwiching foam board in between two layers of plywood. Has anyone done that? Any suggestions.? I am particularly trying to understand whether the foamboard can take the weight ok. How might I figure out which boards can withstand the weight of being lived on, underneath a layer of wood?
Any suggestions would be welcome. Thanks in advance.

[Bob Rowlands]

Absolutely doable. Research 'SIPS floor panels yurt' online for details. Plenty of info about 'SIPS' systems there.

[Jafo]

Steve at

Surely Yurts

did that with mine. It worked out fine.

[Jonroth]

Thanks! I am wondering which foam boards are appropriate for the purpose, or is all of them take the weight ok. ANy thoughts?

[Bob Rowlands]

I'm no structural engineer. Foam board loosely inserted into the void between framing members and panels, and not glued to the framing or the panels, and not completely filling the void between the panels, is not going to stop the subfloor sheet from deflecting when you walk on it. Fill that void with spray foam that completely fills the void, and sticks to everything like a mofo, and it will absolutely stop any deflection whatsoever. The foam sprayed into a rotomolded $400 Yeti cooler adds a lot of strength.

[Jonroth]

Well, I am actually wondering about the possibility of sandwiching the foam boards between layers of plywood without and joists or sleepers- just plywood on a continuous surface of foamboard on another plywood floor. Trying to find out if the foam would take that sort of weight without compression damage.

[Bob Rowlands]

OK, now I see where you are going with this. Your idea is to glue/spike foam board on top of the deck platform, and then glue/spike another layer of subfloor ply on top of the foam board. I'll assume the foam floor panel system is within the yurt, not under the wall. The weight of the yurt plus roof load is not bearing on foam. Just supporting people refer stove etc. Hmmmm.....I don't know...maybe.

I haven't done that, seen it, or heard about it, so I can't offer a worthwhile opinion. Hopefully someone else that has done it, will comment. Otherwise you need to talk with manufacturers of foam, or yurt builders, or just do some research on the 'net. Ask 'Fine Homebuilding' team. They might know. Good luck.

[Jafo]

I absolutely know Steve over at

Surely Yurts

does this and I am also sure he would be happy to tell you how. You can contact him here and let us know what you found out:

Contact Grandma Shirley's Yurt Co.

[Yurtmasterken]

everyone beat me to it. If you buying your yurt, check with the company. Most offer SIP pre-cut to diameter.

ken

[thebitmaster]

I have a small 12" yurt I've lived in full time for five years in Texas and that's how I did mine. I used 2 layers of OSB with foam sandwiched between them. I don't think I glued anything because I was building for portability. The platform comes apart into 4x4 pieces for easy transport. Clearly filling the gaps in and glueing things in makes them stronger and less drafty. I haven't noticed any sag. On top of the second layer of OSB I put cork flooring, which overall has a been a big success. It can pucker if exposed long-term to

moisture

, but otherwise feels good and wears well.

Scott