Does moisture barrier padding work?

A waterproof padding that eliminates worries about spills and pet accidents on my carpet?

I’ll take it.

Or is it too good to be true?

That’s not a simple question to answer, but the purpose of this article. I’ll cover what moisture barrier padding is, does it do what it claims, and more importantly, should you buy it.

What is moisture barrier or waterproof padding?

Let’s start with the basics:

Moisture barrier padding is floor padding that has layer that prevents liquids (spills, urine, etc) from passing from the floor to the floorboards, and it also prevents vapor from coming up from the base floor (concrete, etc) through the carpet.

The hope of this type of padding is to make moisture less of a headache. Your dog’s pee can be removed by simple blotting it up… you don’t have to worry about ripping up the carpet to clean the subfloor (padding or plywood) to get rid of the smell. OR you don’t have to worry about basement moisture seeping through your floor.

Does it work?

It definitely is waterproof. A salesman can hold up the pad, dump a cup of water on it, and show you how the water sits on top of the pad.

The problem is this doesn’t always solve your problem, and it sometimes makes your flooring problems worse.

That’s what we’ll cover below:

Why a small crack in the moisture barrier is a big problem

Some people buy moisture barrier padding and are disappointed because it actually made their moisture problem worse.

Picture this:

Your dog pees on the floor. It seeps through the carpet and hits the padding. The moisture barrier holds the urine on top of the padding, except there is a crack in the moisture barrier where urine seeps through.

Now, the liquid is trapped under the padding because the barrier doesn’t allow it to evaporate back up. Pooled water in a dark space is a great habitat for mold growth. Not good.

Okay, so you make sure your moisture barrier doesn’t have any cracks in it. It may not be so easy…

Good installation is critical

“Cracks” in moisture barrier can happen in a few ways:

Sometimes the edge where the wall and the padding meet has a gap, sometimes the moisture barrier is installed with staples (this makes little cuts in the barrier), and sometimes it’s not sealed with the proper tape.

Long story short: correct installation of moisture barrier requires an installer that knows what they’re doing. (shameless but relevant advertisement: you can click this link to get free estimates from 3 pre-qualified installers in your area)

I don’t recommend moisture barrier padding for basement moisture in most cases

You might find a retailer who sells you moisture barrier padding to fix your basement moisture problem. But when you really think about it, moisture barrier padding doesn’t make sense in a basement. Basement moisture comes through the ground, and it’s going to whether or not you have a barrier in place.

In fact, the moisture barrier could make things worse, much worse. The barrier will do its job to repel the moisture, but now the moisture is trapped between the concrete floor and the pad. The stale water acts like a petri dish for mold.

Now, there are exceptions to this. If you have a mild moisture problem, sometimes putting a vapor barrier under your floor can prevent it from warping. So I’m not completely against preventing vapors from seeping up.

However, I still go back to the fact that if you have a vapor/moisture problem, it’s not worth the risk of installing flooring in that room. At least, don’t install flooring that can be damaged by the moisture.

I do like moisture barrier for pet accidents

Animal urine is one of the most common moisture problems facing homeowners, and it’s also one that moisture barrier padding can make much less problematic. Typically, urine absorbs through padding and into the floor board. Eliminating the bacteria and odor from urine that’s penetrated the padding requires pulling up the carpet and pad—not a cheap fix.

This is where moisture barrier padding comes in. If it’s installed correctly, the urine will pool on top of the padding, instead of penetrating it. Then, the fluid can be sucked up without seeping into the floorboard. Keep in mind, if you don’t get all of the urine up, it will be sitting on top of the padding and underneath your carpet, which can lead to a pool of bacteria.

It’s worth investing in professional (see above) help to make sure as much of the urine as possible is removed.

What about newer, breathable moisture barrier pads?

What if you could have a padding that acted as a barrier to spills and urine from soaking into the floor below, but was “breathable” in the direction of the subfloor to the carpet? Theoretically, this would eliminate all of the problems of moisture barrier padding (trapping moisture between the subfloor and padding) and would still have the benefit of stopping urine and spills from absorbing through the padding.

Today, this padding is available, or at least it claims to be. I haven’t heard feedback from enough people using it to see the results, but I do like the idea of this type of pad.

That said, I don’t think it changes what I’d use the pad for. I’d still consider moisture barrier for pet problems and spills, but I’d avoid it for basement moisture.

Captain’s tips on what you should do now:

Moisture barrier padding is one of those newer inventions that comes with a lot of marketing hype. Hopefully, this article helped you cut through it.

I don’t think it gets the thumbs down for everyone (looking at you pet owners), but you have to make sure that you have a knowledgeable installer. Also, make sure you’re not in the camp of people where it will make the problem worse.

Here’s what I recommend you do next:

  1. Consider getting the opinion of a pre-qualified carpet installer by clicking here.
  2. Check out our carpet padding page to get an unbiased look at all of your padding options.
  3. If you plan on buying carpet, check out our unbiased carpet buying guide if you haven’t already.

Still have questions on moisture barrier padding? Let me know in the comments below.

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Becky Townzen
19 days ago

I have tore the carpet out ,pet urine and moisture built up over time carpet wouldn’t dry. Padding looks ,spill proof padding. Could i put new carpet over existing pad ? Or do I have to replace all of it ?

2 months ago

We just moved into a new house and surprise! the whole basement was used as a bathroom for the previous owner’s pets. We don’t have pets (and don’t intend on getting any soon). Our installer recommended a rubber pad in the basement but I’m concerned with the breathability of the rubber on the concrete. What are your thoughts?

Stevie Good
3 months ago

Within the last year we replaced the carpet in a couple bedrooms of the house. Beneath the carpet is parquet wood flooring and beneath the parquet is the concrete foundation/subfloor. The parquet in the left room, before we ever dove in, had loose tiles. We thoroughly went throughout the room and plucked up all the loose tiles and re-glued them back into place. Before we decided to go back with the carpet, we were going to repair and refinish the parquet, hence having re-glued to loose pieces. We also removed the tacking strips for the carpet, but only in the… Read more »

Peter S
4 months ago

I’ve just started reading up on replacing carpeting in our house. Do I need moisture barrier padding if I have a good carpet with high quality stain and pet urine resistance?

Joe D
8 months ago

I just had some bedroom carpet installed today. I had bought it from a very reputable, 30 year old local business. I chose the most expensive padding available party because of the two sided moisture barrier it promoted. It went over a concrete slab foundation and I wanted to insulate and avoid humidity. I checked on the installers as they were beginning to lay the carpet, and noticed they didnt tape over the seams in the padding. When I questioned it, the lead installer said it doesnt need it because they used glue so the pad wont move. It seems… Read more »

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