After stripping the flooring to the bare concrete slab, I removed the wood trim at the bottom of the wall. There is an irregular 1/4" gap between the slab and foundation along the complete length of the outside walls. Most likely, the gap is due to shrinkage over the 40 years since the house was built.
I'm planning to install a Pergo-type laminate floor over the recommended vinyl vapor barrier. I'll extend the barrier up the walls 1-1/2", so it covers the gap but will be concealed by the new floor molding. Should I fill the gap, with caulk or some other flexible material?
Many houses have a french drain for drainage where the slab meets the walls. Though it's usually wider than 1/4", more like an inch.
Also, your construction technique here seems a bit odd, as is sounds like your planning on putting the floor molding right up against the foundation wall? No inside wood framing or furring stips for sheetrock or similar?
I'm a bit confused ........ is the gap on the outside of the house or is it the gap on the inside, between drywall and the slab? It is normal for there to be a gap on inside at the bottom of drywall; it is the reason for being for baseboards. If drywall went to the floor, it would not allow for expansion/contraction or settling.
When we repainted and tiled our LR/DR, I put color-matched caulk along the baseboards all around. I was thinking, at the time I did it, that wet mopping might get under the baseboard a little bit, get absorbed by bare wood and cause the paint to crack or peel. It was only a few months later that our washer hose broke and flooded kitchen and DR. Caulking the baseboard helped contain the flood :o)
We have a neighbor who had a brand new Pergo-type floor whose water heater died and flooded his place, ruining his floor. The vapor barrier is great for protection from moisture outside the layer of flooring, but you need to prevent any water from inside getting under the flooring - it is composite and will be trashed by water.
I don't have Pergo, and would not want it for that reason. Pergo instructions, in part: "The expansion spaces, all expansion spaces,between the Pergo flooring and walls, the doorway transition or other fixed objects such as pipes for radiators, sinks, water supply to water closet or toilet flanges MUST be sealed with Pergo Sealant or 100% mildew-resistant silicone. b. The space around the perimeter of the Pergo floor must be 1?4" wide and sealed prior to installing the wall trim. The 1?4" expansion space must be completely filled with sealant to avoid water getting underneath the floor."
Here is a link:
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As I understand laminate flooring, keeping moisture out of it is CRITICAL.
It's a reasonable assumption since most slab homes do not have the foundation wall above grade. Usually just a footer and slab with sill plate on the perimeter. But who knows, it could be a unique construction.
In any case, I would seal it unless the OP can find evidence it really is a drain (like a drainpipe or sump pit nearby) Use a flexible caulk urethane caulk should be effective and not too expensive. Silicone or Silicone II caulk will work albeit at a higher price. Don't bother with latex caulk, it keeps airtight but will fail if water pushes from outside. Even if there is not a water problem, sealing will keep things like radon gas out (if your location is prone to that)
I was going to cancel my last message - my brain finally clicked in. So, it's a basement. Back to the Pergo instructions.........also say not to install the flooring on a floor with a sump or a floor drain.
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