Re: basement floor & wall insulation & vapor barrier
As mentioned in the reply to your private message I'll throw out some thoughts here in your thread.
Originally Posted by LandKDIY
The first place to consider before finishing a basement is the exterior of the basement.
It's important that there are no issues from landscaping sloping toward the foundation and proper drainage .
Along with proper exterior waterproofing applied on the exterior of the foundation walls with properly functioning weeping tiles ( exterior footing drainage ).
Reason being --- before investing time and money into finishing a basement you want to ensure there won't be any chance of water infiltration than can ruin those thousands of dollars invested.
There are too many folks that finish basement spaces without ensuring the conditions are favourable before proceeding --- later to be tearing out ruined walls and flooring from moisture-- along with all sorts of mold issues.
So, having said all that ( or my rant for the day ) ............
Yes , applying XPS rigid foam directly to the foundation is a superior method of insulating the space. This provides a continious and uninteruppted insulation thermal break, along with the low permeance value of XPS also provides the needed vapour barrier.
In your case you also have the cripple, or knee , or pony wall ( whichever term you like ) that's framed on top of the masonary part of the foundation. Usually these types of wood framed walls are conventionally insulated with batt insulation placed in the stud bays , covered with over with a poly vapour barrier ( or in the case of you folks in the US you may have, instead of a poly vapour barrier, faced batts which has been removed from the market place in Canada a long time ago ).
If you end up with a *shelf* -- the masonary part of the foundation is thicker than the wood framed upper portion -- you can leave the insulation in that cripple wall in place and if covered with a poly vapour barrier this too can stay -- as an option.
In which case the XPS can be applied to the lower masonary part of the foundation and up to the bottom of the cripple wall. At the point where the two different materials meet you can use foam in a can to seal the seam or use a house wrap tape.
Otherwise, you can use the XPS all the way from floor to ceiling ( including the rim joist area.). Just make sure to remove any existing vapour barrier first.
Make sure to seal all seams with foam in a can or house wrap tape.
The floor ........
XPS about an inch thick can be put down on the concrete floor sealing all seams -- lay 5/8 plywood over top and fasten through to the concrtet below.
This provides a warm , good base for any type of finish flooring you wish to apply.
The XPS also provides a vapour barrier between the concrete and finish floor.
Another option is to apply a plastic dimpled sheet good over the concrete floor coverd over with 5/8 plywood. The dimpled plastic sheet can be found anywhere that sells foundation waterproofing materials. Two products by Platon and Superseal work very well.
With this arrangement you end up with an air barrier ( created by the dimpled plastic ) as the insulation but also allows any water seepage that may occur to flow freely toward the drain and won't contact the plywood sub-floor.
There is a product called Dricor which is basically the same concept as above. It comes in 2ft X 2ft tongue and groove panels with a plastic dimpled adhered to an OSB panel.
2 cents worth.
"" an ounce of perception -- a pound of obscure "