Just moved into a small cottage on a slab. House sits on a hill over deep
sand, so no drainage issues. Summer and winter, a semi-finished room has a
damp concrete floor - sometimes, the water even pools slightly. I'm pretty
certain that it's condensation rather than intrusion from below or sideways.
I'd like to finish the room, and wonder about sealing the slab before
putting down linoleum or something else. Is there a best solution to remove
the (small amount) of accumulated salts? After that, should I dry out the
room with heat and then use epoxy paint, or what?
If it is condensation, then sealing the floor will not change a thing.
If it is not condensation, then you need to tackle the problem from the
outside to keep the water away from the foundation or remove it before it
gets to the foundation.
I might suggest that if it is condensation (easy check - tape a square
of aluminum foil on the floor. In a couple of hours come back. Moisture on
top is condensation moisture under is coming through the concrete.
Condensation forms on a floor in a puddle ? I never heard of that and
think you need a cold floor and very hot humid air to make that
happen, Right. Do your cold water pipes consense , that would happen
first before the floor if it was condensation. You cant paint it till
it is dry, to me it sounds like ground water. Get a moisture meter and
the floor will need an acid wash for paint to bond. If it ever dries
Hey - luck is with me for once. I noticed that it's only wet on warm humid
days after cold night, whether or not it rained. Mopped selected areas of
the floor with plain water, and after drying they stayed dry. So I'll clean
it all carefully, and paint with epoxy paint or just put down tar paper
Thanks for suggestions-
Don't need one - that's the beauty of it. It was just an accumulation of
hygroscopic salts on the cement that created the problem - first time I've
seen this. When I washed them off, no more condensation, even on the wettest
day of the year and after a cool night. Drainage and air circulation here
are excellent, so everything should be fine. Pre-treatment before linoleum
probably isn't necessary, but is easy enough.
Pound a hole in the floor, and put in a sump and pump,
then put 1/2" of foam insulation, and 1/2" plywood, on
top of which you put whatever flooring you want.
The sump should take care of any water from outside,
and the insulation will take care of any condensation from
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