[Username10]

It’s a house from the 30’s. I just added carpet Squares early spring this year. We’ve had a French drain in our basement for about 10 years. I noticed a mildew odor and i found out this morning after lifting a square (they’re not glued) that only the ones on the perimeter have mildew underneath. I’m not terribly surprised but at the same time these squares weren’t cheap and i hate to just abandon the carpet idea.

I work in people homes and noticed recently another homeowner had an area rug in his older basement and it gave me an idea. Maybe i could replace the perimeter squares with something more breathable. These squares have a rubber membrane on the bottom so i figure that’s trapping moisture.

Any creative ideas?

 

[chandler48]

Ceramic tile and a large area rug. Carpet and laminate flooring are the last two things I would install in a below grade situation, especially one that has had potential moisture problems (french drain)

 

[Username10]

Thank you for that. I should’ve known. Hopefully i can sell the carpet squares on eBay for at least half of what i paid $700

 

[Bud9051]

A friend used carpet squares for a quick conversion of his garage to an entertainment area. When done he stacked then on the side to get his car back in. Was great for our card games.

Very difficult to eliminate moisture vapor coming up through the concrete and anything that blocks it allows it to accumulate as you discovered.

Best
Bud

 

[Username10]

Oh nice. Yeah they seem like such a great idea. I always had concerns about moisture. I underestimated what seemed like zero moisture. I’ll start off by lifting the perimeter squares until i get some tile or something.

Too bad i can’t just seal the perimeter sub slab out a foot to stop the migration of moisture?

 

[Bud9051]

Movement of moisture and moisture vapor is one of the laws of physics, always trying to equalize any difference, wet moves to dry. If you seal the perimeter that moisture will just continue to migrate towards the middle. Even if you sealed everything the moisture level would increase until everything under and around the foundation was equal.

By allowing the floor to dry to the inside you reduce the accumulation and things don't get wet. It sounds like you have most of the moisture problem under control, just avoid any flooring that blocks the drying to the inside.

Bud

 

[Username10]

Yea just funny how it only goes for the perimeter carpet squares. Where the French drain is. Please don’t think I’m arguing i just don’t want the hope to distinguish lol.

FYI there’s never been visible moisture since the French drain was installed 10 years ago. So yes, i see it also as moisture wicking up through the concrete regrettably. Funny we have carpet in the other finished half of the basement and there’s no smell there. It was professionally installed by Lowe’s many years ago so maybe they did something different or the carpet just breathes better i don’t know but it kinda gave me a false sense of confidence i guess.

 

[Nealtw]

It’s a house from the 30’s. I just added carpet Squares early spring this year. We’ve had a French drain in our basement for about 10 years. I noticed a mildew odor and i found out this morning after lifting a square (they’re not glued) that only the ones on the perimeter have mildew underneath. I’m not terribly surprised but at the same time these squares weren’t cheap and i hate to just abandon the carpet idea.

I work in people homes and noticed recently another homeowner had an area rug in his older basement and it gave me an idea. Maybe i could replace the perimeter squares with something more breathable. These squares have a rubber membrane on the bottom so i figure that’s trapping moisture.

Any creative ideas?

Tell us about this french drain, if done properly the water should be well below the slab? Was it put in a trench or is it a box drain against the outside wall?

 

[Username10]

It’s below the slab. I was finished level with the existing floor. Two sump pumps, one in opposite corners of the basement and when it rains, often they are running water out. There’s drain tile between the wall and the floor and a plastic frp like material which i think is supposed to catch water in the event the walls were seeping but they never do and direct it into the drain tile.

Makes you wonder how would the water migrate up through from the drain tube and the filler rock?

 

[Nealtw]

It’s below the slab. I was finished level with the existing floor. Two sump pumps, one in opposite corners of the basement and when it rains, often they are running water out. There’s drain tile between the wall and the floor and a plastic frp like material which i think is supposed to catch water in the event the walls were seeping but they never do and direct it into the drain tile.

Makes you wonder how would the water migrate up through from the drain tube and the filler rock?

Like this or like that.

 

[Username10]

Probably more like the bottom. We paid $5000 for a 1000 sf perimeter. It was 2 weeks before Christmas and his last job of the year lol. I think i see what you’re getting at. Good grief.

 

[Nealtw]

Probably more like the bottom. We paid $5000 for a 1000 sf perimeter. It was 2 weeks before Christmas and his last job of the year lol. I think i see what you’re getting at. Good grief.

That system has water in contact with the slab before it gets to the drain so wicking is almost a sure thing.


In the better system.
See they have sheet poly on the wall to catch any leaks the poly under the slab should be part of the wall poly in one piece or taped.

 

[AllanJ]

Won't mildew develop behind the poly' sheet on the wall and behind the black plastic angle?

 

[Nealtw]

Won't mildew develop behind the poly' sheet on the wall and behind the black plastic angle?

Only if you alloy warm moist air to leak thru the wall and the insulation to come into contact with the poly.

 

[Username10]

So since the moisture is wicking through only on the perimeter i was thinking of removing those tiles and painting the slab with sherwin Williams porch and floor enamel in a color that will help the floor at least have a finished look. The room is kind of a multipurpose room. Laundry, office, exercise, storage so i think it’ll suffice.

Do you think the paint might force the moisture to migrate to the “inland” tiles OR will the latex paint allow the moisture to evaporate and enable the French drain surface to “breathe”?

I get that this can be mostly theoretical. I appreciate your opinions. I’m trying to avoid “throwing the baby out with the bath water” if you will.

 

[Nealtw]

If it wasn't a problem before you put carpet down, I would leave it bear concrete and let it evaporate and track the humidity in the room

 

[SeniorSitizen]

The same thing can happen on a concrete floor without a basement and excellent exterior perimeter drainage. A rubber backed industrial throw rug, for muddy boots, just inside a shop door will ( some days only ) depending on atmospheric conditions, form water under the throw rug but never in the more interior areas of the floor. It's really no mystery, and certainly not caused by Aliens.:wink2: