Basement Subfloor and process

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snowsik
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Joined: Fri Sep 27, 2019 9:21 am

Basement Subfloor and process

Post by snowsik » Tue Oct 15, 2019 10:01 am

Hi so I'm in the midst of a basement remodel at my house. The walls I am doing XPS foam board and a stud wall with batt insulation in the cavities.

For the floor I've decided to do XPS foam board (1inch) with OSB laid on top and then laminate flooring over that. I know XPS foam board is essentially a vapor barrier, should I still be laying down a vapor barrier roll? and if so do I put it down prior to the foam board i assume?
I'm also wondering about what i should be putting between the osb board and the floating laminate floor? Someone mentioned I should have some sort of underlayment there as well or else the floor and the osb will click when walking.

Last question also related to the wall/flooring connection. So I have my foam board up on the walls currently. Should I be putting my bottom plates (pressure treated) right on the concrete or over some kind of vapor barrier. I saw a video online that said to put down the subfloor first and just anchor the wall to the OSB board, but that didn't sound to stable to me, I had planned to drive the bottom plate into the concrete with a ramset and just have the subfloor but up against the bottom plate on one side and the wall insulation on the other. Should I be adding an additional moisture barrier wrap between the stud wall and the xps foam on the walls also or can i just build the wall right against the xps foam board? (i was concerned with the batt insulation getting any moisture into it.

Apologies for all the questions, once I got typing realized I had more than I thought!

Thanks in advance!

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Shannon
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Re: Basement Subfloor and process

Post by Shannon » Tue Oct 15, 2019 10:04 pm

So first off I would use T&G OSB sub flooring , this will give you a better surface and more stable. I also personally would not bother with any poly on the floor if you are using the foam.

For the walls they could be ontop of the subfloor or directly on the concrete , your call really.
If you use PT bottom plate then no barrier between that and the concrete is needed . If you however used standard untreated lumber then you need something, poly, or foam gasket works well.
You do not need anything else but the foam on the walls for moisture, install the foam, frame the walls about 1" to 1/2" infront of the foam. The space allows for un plumb or un straight concrete walls.
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snowsik
Posts: 3
Joined: Fri Sep 27, 2019 9:21 am

Re: Basement Subfloor and process

Post by snowsik » Fri Oct 18, 2019 7:06 am

Thanks Shannon!

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