Question for insulating a slab

[soapii]

This post is concerning my basement not my garage but I figure the knowledge base still applies. I’m getting ready to finish my basement and looking for some insight/experience with insulating a slab. Currently the basement is completely unfinished, just concrete walls and floor. When we built the house we put rigid XPS around the exterior walls and they spray foamed all the floor joist pockets. My plan is to do a heated floor (using Thermosoft) but I want to insulate the slab so that all my heat isn’t going right down into the slab/earth.

So my question is……..which of the following is the better way to go about this (or is there an even better way)?

1) Run pressure treated furring strips along the slab with XPS between them (both ¾” thick), then place the T&G subfloor down, then heating mats and carpet/padding.
2) Cover the whole floor with XPS, then put down furring strips, then place the T&G subfloor down, then heating mats and carpet/padding.
3) Other suggestions?

Problem with #2 is that the floor section ends up being ¾” thicker so I lose ceiling height (not too big of a deal) but then I do have to deal with that extra thickness at the stairs.

I appreciate your time and information.

--Joe

 

[soapii]

Another option I read was putting down the XPS then the OSB directly on top (no furring strips). Using Tapcon screws to go all the way down into the slab.

--Joe

 

[buddyboy]

yeah the xps then osb over with screws that is the way i've seen it done.

a little PL premium to hold the foam on the slab and some to hold the osb to the foam.

at the bottom of the stairs you can leave just the bare slab with no heat or insulation and make it like a 'landing' 3'x3' or whatever... cover the bare slab with something not so think like tile or carpet glued right to slab

good luck

 

[soapii]

a little PL premium to hold the foam on the slab.

This is the stuff I was recommended to use on the slab...

http://www.homedepot.com/p/Loctite-PL300-10-fl-oz-Foamboard-VOC-Adhesive-1421941/202020476

I guess I could use it between foam and OSB too.

Do you know of any issues with the PL premium and melting the foam?

--Joe

 

[buddyboy]

or you can make a box landing at the bottom of the stairs the same height as the bottom stair, i would think it would need to be larger floor area so people would have to take a few steps on the landing before going up the steps or coming off the landing

 

[buddyboy]

i've put the PL right on foam and although it takes forever to dry it doesn't melt or anything... if that stuff was made for foam then I'd use that. the adhesive is just to help keep the floor 'solid' and not 'bouncy" if that makes sense.

 

[soapii]

or you can make a box landing at the bottom of the stairs the same height as the bottom stair

Great idea, I like that!

--Joe

 

[burleyfarm]

At the far end of my 28' X 40' pole barn I partitioned a 12' X 28' section off for two rooms. In my paint booth I went with 1" foam, radiant bubble insulation and Wood flooring. Screwed with Tapcon's. Also used the same method in an adjacent room with carpet as the finished flooring. The slab has 6 mill vapor barrier under it.



Dave Burley
Sent from my tractor seat.