Since more and more of these types of products are being sold and used I wanted to share with you a recent claim that resulted from a moisture barrier pad. The consumer had carpet in her home that had been down for several years and replaced it when they did some renovation to the house. This house is about a half a block away from the beach and has a crawl space under it. When the consumer went to buy new carpet she was sold a moisture barrier pad because she has pets. She was concerned about the pets relieving themselves on the carpet and having it go into the pad and the floor beneath it. The dealer told her this moisture barrier pad would be a good product to use because it would prevent any pet urine from going into the floor.

After about a year the consumer noticed she could not get a closet door open, because the floor had warped. When she investigated she found that everywhere in the house where carpet was installed the floor warped. She was amazed that this was happening, as anyone would have been, since she had lived in the house for about 17 years and had never experienced anything like this. The only thing that was different was the new carpet and pad. When the carpet and pad were pulled up it was immediately revealed that the plywood subfloor was damp and as a result, it warped. When they went under the house they found no sign of moisture that would indicate a massive intrusion of water.

Being so close to the beach on the ocean this house sat on land that had a naturally high water table. The water vapor being emitted from the earth had been there all along, it wasn’t anything new. The old carpet had a foam pad beneath it that would allow moisture vapor to pass through them and naturally evaporate into the air. With the replacement of the old carpet and the addition of a moisture barrier pad, which had a barrier on both sides, the moisture, in the form of a vapor, could no longer evaporate through the floor. Instead, it was trapped beneath the pad at the wood floor allowing the wood to absorb the moisture vapor, which eventually saturated the wood, resulting in it warping.

All of the affected plywood is this house has to be replaced. What happened here and who’s at fault? The use of this type of pad in this location caused the problem. Being this close to the water, a house with a crawl space and earth beneath it, whether it has sand, gravel or any other material, is going to have a high level of moisture vapor emission. If you block the moisture, trapping it in the wood, the wood will absorb the moisture and be adversely affected by rotting, warping or lifting. The dealer should have thought of this. Granted, he would have had to understood the situation, but he is responsible because he sold a product which created the problem. The pad manufacturer should also know that this type of reaction can occur with their product when there is ground water or a high level of moisture in the earth beneath the house. Now if you’re thinking, “but yeah, Lew, how were they to know?” They are supposed to know. If you offer a product for sale you have to know the positive and negative sides of it. If it will cause a problem when moisture in the substrate or earth exists, the manufacturer should understand how his product will affect this natural condition, it’s common sense. The manufacturer of the pad then also has a responsibility for the damage caused to the subfloor.

Replacing all of the plywood is going to be a very involved and expensive task. They don’t know yet if the floor joists were affected but if they were, they too will have to be replaced. Any way you look at it this is a major undertaking and imposition for the consumer and it’s not their fault. The carpet by the way is fine and it has no responsibility in what has happened. Once the floors are replaced, the carpet can go back down over a pad that has no moisture barrier properties.

I’ve commented on these moisture barrier products before. The first issue of concern is that even if they stop moisture from going into the floor, it has to pass through the backing of the carpet first. If the moisture happens to be pet urine it doesn’t make any difference if it doesn’t get to the floor because once it gets into the carpet backing and the latex it’s near impossible to do anything about it. The only way to fix it then is with a flame thrower or a knife. The carpet is basically ruined once you invade the backing with an aqueous, residual, odorous substance. Unless you stop such an invasion of the carpet, above the carpet, putting something beneath it to stop moisture from going into the floor is, in my opinion, kind of stupid. It would be like wearing a bullet proof vest, beneath your skin. It would stop the bullet but not before it ruined the wearer.

This is one of those cases where a product that sounds like a good idea, isn’t. Creative marketing it may be but when you stop and think about it, it’s not logical, useful or effective. And in this case it really backfired. Don’t let this happen to you. This makes a plain old defective carpet look real good.