Moisture barrier

[ford35lh]

Whoever put down the concrete floor in my garage neglected to
put a moisture barrier under it. Since I moved in I have put down
a layer of poly a few times and need to do it again.
Its unheated and uninsulated.

Has anyone tried a paint that will not let moisture pass thru ???

[34fordy]

With respect, I do not believe that moisture passes through the concrete. The moisture is in your building and the cold floor draws the moisture from the air. This is just like a cold glass of beer or water in the summer that starts to drip water down the side of the glass.

[38bill]

I would think an epoxy paint would work best but any paint can blister if there is too much moisture.

[tomcarman]

Concrete is most certainly porous and permeable. Meaning it absorbs water and it is flexible. Microscopic voids allow water to enter and when under hydrostatic pressure from the ground upwards will indeed infiltrate. Subsoil conditions are a factor, particularly over say a substrate of clay where water cannot percolate. The mixture, or some would say "hotness" of concrete is also a factor. In a typical residential application the mixture isn't very "hot", thereby resulting in a softer and permeable slab. Without a vapor barrier below it will be very difficult to stop water infiltration. A whole house perimeter drain system may be of help. I have also seen success with a sump pit and pump. 34Woody is also correct in that interior condesation will occur. Law of physics in a nutshell? Cold air meets warm air condensation occurs.

[tomcarman]

34fordy. Sheesh, where's my mind. Woody? Seriously? Ask my wife.

[34fordy]

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Originally Posted by tomcarman

34fordy. Sheesh, where's my mind. Woody? Seriously? Ask my wife.

I am 75 years old. A woody would be great! LOL

[5851a]

Humid in my area and every time garage was opened condensation on the floor. I used the old carpet from the house and laid it in the garage and helped a lot.

[Kube]

I have always had thick plastic placed beneath any concrete I've had poured. It makes a world of difference in any situation.

[alanwoodieman]

there is an water based epoxy that we got from lowe's. we used this in my son's garage and it really helped. while we were doing this we also got some sort of anti-slip to go in it, ground glass I think.

[KiWinUS]

I had the same problem with my lil garage built in late 40's Just over a year ago I turned it into a studio for my daughter & needed to fix the problem & after some research used "Sherwin Williams Armourseal Rexthane" It is amazing turned this well used floor into a showpiece (well compared to what it was) It is resistant to almost everything. No primer needed single stage , must use correct respirator as it is powerful. Goes on easy is expensive fortunately we have a friend thats a store manager. If completely fixed moisture problem, I highly recomend it.
Good-luck!
Cheers
Tony


Kurt makes a great point. I will add my garage is well above grade in well drained ares. Anything like paper or wood absorbed moister through the old floor, or a 5gal bucket of lacquer thinner would always be wet underneath, rusted the bottom out of my nut & bolt bins.Just a few of the issues I had.

[Kurt in NJ]

Another thing to look at is drainage---- is the garage floor below grade( the level of the dirt outside--- when it rains does water puddle against the walls, I used to have water in basement when it rains, found the ground sloping toward the house, fixed the grades and extended some of the downspouts away from the walls and mostly cured it
If part of your floor is below grade you might have to dig around the outside and put in some drainage to allow trapped water to escape

[Vics Stuff]

If you have heat in that space , which will dry the space out causing a wicking effect of the slab from the ground under the slab . As mentioned from previous posts without a vapor barrier under the slab you will always have water issues , unless you seal the slab surface as mentioned also. Make sure that you seal the edges well against the foundation.
Vic

[Tony, NY]

If you want more opinions, you can go to our sister forum The Garage Journal. Here is a sample for moisture barrier. https://www.garagejournal.com/forum/...isture+barrier

[B-O-B]

I had a problem with water seeping thru the block wall in the garage. They make a paint that will stop the leak. I can't remember tho as it was 30+ years ago. Google block wall sealer.

[flatford8]

I used Dry-Lok on the low block wall of my place. Stopped the moisture from coming thru when the rain dripped off the roof.......Mark

[flathead48]

You might want to check with a local ready mix co, they are very knowledgeable and might know a good sealer.,