Insulated concrete slab compatibility with linoleum or vinyl plank
This is my first post – hopefully it’s in the right category.
Our house is ~20 years old. For the last 15 years, I’ve has wall-to-wall carpeting glued directly to the concrete floor in my basement. No functional problems.
I’m looking to replace the carpeting with something that is durable, stain-resistant, and long lasting. Current front-runners are Marmoleum (linoleum, so “greener”) and a FloorScore-certified low-VOC vinyl plank (Karndean).
According to our plans, the concrete floor assembly is:
– unsealed 4″ concrete slab (with a smooth but unsealed surface)
– on 2″ Styrofoam SM
– on 6 mil poly (BUT I’m not 100% confident that it’s present)
– on 6″ of compacted gravel
The concrete is apparently dry (never feels or looks wet). There is no sump pump (outside drainage is good). Location is Eastern Ontario, Canada.
Marmoleum pre-installation steps require a slab alkalinity and moisture check. I don’t yet know what the pre-installation steps are for vinyl plank.
Should I be concerned about mold, or adhesive (or other!) failure, from moisture that will now be contained/trapped within/on the slab by the new, effectively impermeable, flooring? Especially given (a) the possible absence of the poly layer or (b) if the poly is directly on GRAVEL.
Thanks very much,
Mark
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Replies
We have had two houses with Marmoleum on a concrete slab.
First one, a fifties era split level, had problems with it lifting after install. (I assume no insulation or poly under that slab.) We had it spot glued back down a number of times before it settled down. And yes, the dealer and Marmoleum rep did moisture tests that came back negative. Fortunately eventually the floor reached "stasis", and we enjoyed it for ten years after.
We have Marmoleum in a number of rooms on concrete in our new home. This house we know had boatloads of gravel, perimeter drains, poly and insulation. Moisture testing was done prior to the install; one of the few positive things about a long build, the slabs had cured and tested dry enough. However, even at that we did have one little bubble at a perimeter wall, easily fixed by the installer.
Our experiences for what they are worth.
Thanks Andrew - this is very helpful information. I assume that since you have Marmoleum in your new home that you're happy with its durability. Would you mind commenting on that?
I'm hoping someone will also comment specifically on the "water vapour consequences" of having insulation + non-existent poly or poly directly on gravel.
Thanks again,
Mark
I used glue down vinyl plank in my house and it's been great. I had a 4" slab, 2" xps foam, 6 mil poly, and a layer of clean stone chips. Slab was well cured at glue down time. No bubbles or lifting at all.
IN a retail space I built out for one of my chocolate shops, I used the Karndeen on the mid-eighties above grade, no-poly-underneath slab and it is great. People think it is real hardwood. The nice thing about it is that if there is one damaged piece, you can remove it and replace just the damaged piece. With sheet goods this is not usually an option. In the stock room I used the much less expensive VCT. In my original chocolate factory circa 1925 building which is a very large arts and crafts bungalow (built with solid poured concrete walls and an 8 foot high basement ceiling, incidentally- I had heavy vinyl sheet goods on the floor of the basement. When I bought the place I ripped that up. It was severely curled in the corners where moisture had loosened the glue. I tore it up and found some evidence of water and some mildew. Nothing too bad. But I bleached the floor, dried it good, sanded it with heavy grit floor sander and laid ceramic tile with a modified thinset. That was about 19 years ago when I spent a lot of time bending my back. It has proven a good investment. If you don't want to use tile, then I recommend the Karndeen.
Mark,
It sounds like your basement slab has good specs. Why do you think that the builder failed to follow the specs? Have you drilled a hole in the slab and noticed that there is no poly?
If you've had carpet on your basement slab for 20 years, with no mold problems, my guess is that your slab is pretty dry.
Everyone: thanks for your replies.
Martin: Poly may well be present - I haven't drilled a hole to check. If it IS present, it's directly on the compacted gravel; I thought that might be a problem (breaks in the poly) because most details I've read about have the poly on top of the insulation, not on top of the gravel. But Figure 2 in the following document suggests it would be OK.
http://buildingscience.com/documents/insights/bsi-059-slab-happy