Commercial slab on grade, moisture problem.

[Brandon Whitmore]

Building: 30ish year old commercial slab on grade

Problem: Water seeped through the slab causing mold/ mildew to carpet.

Questions:

1)When were vapor barriers first required under slabs?

2)If there are drainage issues against the foundation, but water only enters in the middle of the slab, would it be a vapor barrier issue, or can vapor barriers only prevent some water seepage?

My buddy is a landscape contractor who does maintenance on a commercial property. There were drainage issues on the property, and my buddy had bid on a drainage system not too long ago. Last month, the irrigation system somehow started to kick on more than it was supposed to. To make matters worse, we had a very wet month of May, so the soil was already saturated. This led to a couple of inches of standing water up against the foundation on the drainage issue side of the building. The standing water was below slab level according to the contractor.

The landscape contractor got a call from the property owner telling him that the carpet in the middle of the building was damp, and there was mold/ mildew growing on the underside of it. The owner is saying that there is 30k in damage caused by the contractors negligence.

Any thoughts/ opinions?

[David Meiland]

Sure are a lot of variables in that scenario. Why does the building owner think the irrigation is the sole source of his problem?

[Jim Katen]

Building: 30ish year old commercial slab on grade

Problem: Water seeped through the slab causing mold/ mildew to carpet.

Questions:

1)When were vapor barriers first required under slabs?

I don't know. But I do know that we were *supposed* to be putting them in in the early 70s back east.

2)If there are drainage issues against the foundation, but water only enters in the middle of the slab, would it be a vapor barrier issue, or can vapor barriers only prevent some water seepage?

Unless it's detailed with extraordinary care (it never is), the vapor barrier won't prevent bulk water entry. That's not its purpose anyway.

My buddy is a landscape contractor who does maintenance on a commercial property. There were drainage issues on the property, and my buddy had bid on a drainage system not too long ago. Last month, the irrigation system somehow started to kick on more than it was supposed to. To make matters worse, we had a very wet month of May, so the soil was already saturated. This led to a couple of inches of standing water up against the foundation on the drainage issue side of the building. The standing water was below slab level according to the contractor.

The landscape contractor got a call from the property owner telling him that the carpet in the middle of the building was damp, and there was mold/ mildew growing on the underside of it. The owner is saying that there is 30k in damage caused by the contractors negligence.

Any thoughts/ opinions?

Has the building owner ever had this problem before?

Was there ever carpet there before, or is the carpet new?

I think it's very likely that standing water around the building could have caused this, but I'm certain that in past years, there's been lots of standing water there. Irrigation systems can seldom produce as much standing water as mother nature does on a regular basis. How was this building in the winters or '96 & '02?

That said, your buddy ought to just call his insurance company.

- Jim Katen, Oregon

[kurt]

A vapor barrier isn't going to do anything in saturated conditions. Inasmuch as most of them are 6 mil visqueen, they don't do much of anything period.

What's the carpet pad? Seems most installers have forgotten that concrete slab installs need the breathable fibrous stuff. If they put down conventional foam pad, they built a mold factory.

What do folks call that fibrous stuff? We call it "hair pad", or "jute", but that's slang; what's the real name?

[Scottpat]

A vapor barrier isn't going to do anything in saturated conditions. Inasmuch as most of them are 6 mil visqueen, they don't do much of anything period.

What's the carpet pad? Seems most installers have forgotten that concrete slab installs need the breathable fibrous stuff. If they put down conventional foam pad, they built a mold factory.

What do folks call that fibrous stuff? We call it "hair pad", or "jute", but that's slang; what's the real name?

We never see anything but foam pads on concrete slab homes. Last time I saw the "hair" pad you are talking about was on a 1960's home that had the original carpet! I don't think I have even seen anything but foam pads in the flooring stores.

My understanding is that the foam carpet pads that are used have a breathability factor and allow vapor to move through.

As for the wet slab??

Water standing along the side of the foundation is not a good thing. It could be that a channel has been cut in the ground by the water and it is being funneled to the center of the slab, I have seen this before.

With a 30 year old building water is just not suddenly going to start seeping up from the ground in the middle of the building unless something has suddenly changed to cause it. That is if it has no prior history of water problems.

[Marc]

What about sub slab plumbing breaks? Either fresh water supply or waste lines. Lotsa possibilities.

Marc

[Brandon Whitmore]

Thanks all.

I wish I had more answers, but that's all he told me over the phone last night. He wanted me to go out there and look things over, but I passed. I stick to residential inspections and to things I know more about. Trying to figure out the exact cause of the water entry could be tough, if not impossible.

[kurt]

We never see anything but foam pads on concrete slab homes. Last time I saw the "hair" pad you are talking about was on a 1960's home that had the original carpet! I don't think I have even seen anything but foam pads in the flooring stores.

The 60's stuff is not what I'm talking about. I know that crap; it's worthless. The stuff I'm talking about now is synthetic woven carpet cusion, pretty soft, very durbable. I've heard it call rag pad also.

My understanding is that the foam carpet pads that are used have a breathability factor and allow vapor to move through.

I think you're right in that it's been engineered and mfg. to breath within parameters, but those parameters are near perfect conditions in the first place.

It's not hard to saturate a foam pad with excessive moisture, where it then retains more water than it breathes. I find it enough to point it out.

Of course, this depends on lots of variables, but the jute pad really breathes excellently; it's the only thing I'd use in any basement or over any concrete slab.