Seal basement concrete floor before engineered wood install?

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Supporting Member
Supporting Member
Apr 28, 2012
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I own a 1940s home with a basement. The walls in some areas of the basement were bowing, which is common here in western Pennsylvania due to wet soil and collapse of the terra cota exterior footer drainpipe. SO we all get interior french drains...

I want to furnish the basement again by framing, hanging drywall and placing an engineered wood floor.

I now have an interior french drain with only a few inches of concrete over the drain trough. The drain was installed 2.5 years ago and there has never been water in the sump. The concrete floor was painted in the past but much of that pain is no longer present. The floor is a very smooth concrete, with no cracks, no flaking, and no evidence of moisture.

1. Should I use concrete sealer on the entire floor?
2. If so, should I use a sealer or a dryloc-type paint product?
3. Do I need to remove all of the existing paint, or can I leave and seal over any intact paint?
4. Any feelings on engineered hardwood? I don't think that it is a truly wet location.


Contractor retired
Nov 4, 2010
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Chiliwack BC Canada
I have seen this glue used, I have not seen the concrete testing before but it looks like a good idea.


Well-Known Member
Jan 8, 2011
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If it was mine I'd be installing as a floating floor over a manufactures suggested vapor barrier.
What's the manufacture have to say?
There should be install directions on line.
All a top side sealer is going to do is keep the dust down and float over the old paint.


Well-Known Member
Jun 21, 2013
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If you've go the height available:
lay down plywood sub floor fasteners are good.
cover that with (and I'm sorry I don't know the name of the product): I found it at a floor supply company -- big boxes might have it. Its pricey (was for me) about $200/5gal. And properly applied (ie thickness) it'll take about 20 gallons to cover 24x12
Then lay your finish floor over that. In this pic the product is what you see. plywood underneath that -- and the entire floor covers old 1960s no vape slab and new slab (see the jog in the wall) with what is probably sub-standard vape protection (ie a heavy plastic sheet) I laid 3/4 hardwood over it 8 years ago and have had zero probs -- the footprint is not prone to flooding, has very little soil, mostly ledge rock and a steep slope on two sides. Even so, I found rotted two by fours in a corner at the unseen end of the wall on the right. the stuff dries to a rubbery consistency.