Foam boards under slab

[Tbender78]

I am gearing up for my slab pour in a couple weeks. I already ordered StegoWrap 15Mil vapor barrier and now getting quotes for foam boards. My question is:

Do I have to tape or somehow adhere the foam boards together?

My build s being documented on this forum under White Mtn. Barn for those of you interested.

 

[Dagny]

you already have the plastic so I wouldn't.

 

[Crawlin]

No tape with a vapor barrier. I am about to put down some 2" Kingspan. I ordered 210 sheets through Lowes and was able to save a lot of money from other suppliers. I am using a Stego 10mil since I am using foam board I thought anything else was overkill.

 

[benwah]

I've never taped polystyrene sheets together. Just fit them together tightly and when you need to make cuts, use a keyhole saw or a wood crosscut saw. Your rebar and/or mesh (depending on what you're doing to your floor) should hold them down nicely.

If you have high winds I'd be sure to lay lumber over them so everything doesnt fly away before the pour.

 

[Tbender78]

Thanks for all the reply’s. I am worried about the wind and the fact that I will be doing this a week or two before concrete shows up. I have a big tarp coming so hopefully that will keep it in place.

 

[The Cobbler]

I taped my foam to keep it together

 

[PWC Repair]

I did too.

 

[ScaldedDog]

Make sure the ground beneath the insulation sheets is prepped well, compacted, and dead flat. If you have air pockets beneath them, you will have cracks that never stop in the floor.

Mark

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