Sealing concrete floor

[Dog Ma 1]

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?

Thanks-

DM

[Joseph Meehan]

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.

[m Ransley]

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 out.

[bill]

[default]

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 the inside.

[Dog Ma 1]

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 under linoleum.

Thanks for suggestions-

DM

[Bill Schnakenberg]

Can you say 'Dehumidifier'?

[Dog Ma 1]

"Bill Schnakenberg" wrote

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.