Generally speaking, I thought the 'proper' basement subfloor method
Vapour barrier, 2x sleepers (optional rigid insulation between),
However, I read an article recently that implies that the vapour
barrier will trap moisture between concrete and create a potential
moisture problem (even in apparently 'dry' basements). Instead, the
recommended method was to apply rigid polystyrene directly to the floor
with no vapour barrier, followed by sleepers/plywood. Supposedly, the
polystyrene allows moisture to pass through and reduces the chance of
Has anyone else heard of this practice? I actually found more than one
article about it...and the use of a vapour barrier appears to be a big
FWIW, I want to install an insulated subfloor suitable for hardwood
installation (with minimum height).
Over by the plywood in the Home Depot are these panels made for what
you are trying to do. They are what appears to be tongue and groove
underlayment supported on a plastic substrate with many channels to let
air or moisture pass through.
Might be worth a looksee.
Borrall Wonnell wrote:
I suspect that particular design is patented so you probably won't see
it separate for a while.
I have see a drainage product from Exxon called "Tiger Drain" that is a
convoluted plastic mesh mat (very strong) with a filter fabric bonded to
one side intended for use vertically behind retaining walls that I
suspect would function as desired if laid flat under your floor
I believe the product you saw at HD was this:
I used it to help finish a room in a walkout basement and it worked
great. Yes, it is a bit more expensive, but here are the advantages I
Small, each piece is only 2' x2', trimming around posts, doors,
closets, etc is much easier.
Portable, I was able to fit an entire rooms worth (50?) of pieces
inside my car.
Easy to handle, one person can do it all. Sure one can handle
4'x8' sheets of plywood by yourself, but it's a pain.
I got mine at Menards (upper Midwest HD wanna be). It's on sale right
now for $4.58 with a $50 giftcard if you spend over $500!
OP here. Surprisingly, the DRIcore system is available at several
retailers in my location, which is (sort of) good news for me. It
seems good for drainage/height, but doesn't appear to have much
insulation value. I don't think it supports a floor covering like
hardwood, so I would likely require an OSB/plywood covering on top of
the DRIcore (long staples, etc.)
My basement is pretty cold, so I have been avoiding DRIcore as an
option despite the advantages. It sells for about $8 (CDN) for a 2'x2'
piece. FWIW, I believe that another company sells a liner system
similar to the DRIcore base. I forget the name of said company.
Any opinions on placing extruded polystyrene (R5/inch) directly on the
concrete floor? That's essentially what I originally asked about.
It will eventually fail if it is actually carrying the floor load. Small
movements against the concrete with gradually grind the PS to dust. If
you shoot down PT 2x material to actually support the sub floor and use
the PS in between they should last.
If you just want th eplastic that's on the bottom of the DriCore you can
look into Delta products.
We used Delta FL in our basement and it's fantastic. Was $187 per roll, and
we used 3 rolls in our 900 sq. foot basement.
Info is at www.deltafl.com
Here are some pics of our install. We placed pergo directly over the Delta
FL product using a barrier in between for sound/insulation/warmth.
e-mail me if you have any questions about this.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.