Basement (concrete) subfloor options

[Borrall Wonnell]

Generally speaking, I thought the 'proper' basement subfloor method was: Vapour barrier, 2x sleepers (optional rigid insulation between), plywood/OSB

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 mold/rot.

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 problem.

FWIW, I want to install an insulated subfloor suitable for hardwood installation (with minimum height).

Cheers, Dave

[bamboo]

[Tom The Great]

I saw that option too, but the price seems a little high. Does anyone sell the plastic part seperate?

tom @

[Pete C.]

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 underlayment.

[TomCase]

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 found:

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!

Good luck!

[Borrall Wonnell]

Hi all,

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.

Cheers, Dave

[e-mail] wrote:

[Pete C.]

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.

[Goedjn]

Glue it in place.

[Chris M (SilverUnicorn)]

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

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.

Chris

[hallerb]

first address any and all basement moisture problems.......... otherwise your just wasting your time

underslab perimeter drain with sump pump

[Tom The Great]

Real sweet, I was looking for such a product. Thank you.

I see you also so used expanding foam, satified with it?

tom @