1/2" Thick Memory Foam Carpet Pad - Do I need a Moisture Barrier Padding or a Memory Foam Pad?

Do I Need Moisture Barrier Padding?

Should I upgrade to a Moisture-barrier pad? What are the pros and cons of moisture barrier padding? 

What is a Moisture Barrier Pad?

Moisture Barrier Padding is a special carpet padding with a layer of plastic on the top. This is to help prevent liquids from soaking through the carpet backing and into the padding and to the sub-floor.

One pad maker says on their website: “A moisture barrier helps prevent spills and accidents from penetrating the cushion, so they can be blotted from the carpet quickly and easily.”

However this statement does not make any sense to me. Once a liquid goes through the carpet backing and lands on the top of the padding, it cannot be blotted up. 

Is Moisture-Barrier Padding Necessary?

Some carpet salespeople recommend a Moisture Barrier Padding or some other type of padding upgrade to almost every customer. Why? Because they make more money. Maybe they actually think this special padding has some useful benefits. The padding manufacturer’s brochure surely says so. 

Moisture Barrier Padding is more costly than a standard Rebond padding. Upgrading to any specialty padding, including pad with a moisture barrier, can cost you plenty. If you upgrade from a standard 6-pound density Rebond pad to an 8-pound density moisture barrier pad, it can easily double your padding cost.

Do you really need to upgrade your padding? In most cases no. however, I find that many homeowners are easily mislead into thinking that a Moisture Barrier Padding can solve some of their problems.

Here is what I mean…

They say that a Moisture-Barrier Pad will prevent spills from soaking through the pad. 

While this is true, what benefit does that provide? Any amount of liquid that is spilled and soaks through the carpet will quickly spread out on top of a moisture barrier pad. Some say that if the padding seams are sealed with duct tape, that liquids will not be able to soak through. You can’t trust this to hold true.


Don’t count on that, because moisture barrier pad is not waterproof.

Carpet Knee-kicker TeethHave you ever seen the sharp teeth on a carpet knee kicker? It’s a tool used all around the room to help stretch in the carpet.

What do you think those 16 razor sharp spears will do to that thin layer of plastic on the top of your Moisture Barrier Pad?


Carpet Power Stretcher TeethThen there is the carpet power stretcher. A tool required to properly install any stretch-in carpet over pad.

Take a look at these long teeth. There’s over 50 sharp teeth that can easily go through the carpet backing and puncture plenty of holes in any moisture barrier pad. 


So, I think that any liquid spills near the pad seams or around the perimeter of any room might easily find a way underneath a Moisture Barrier Pad and become trapped underneath. Is that mildew I smell? 

Carpet Cleaning Limitations

When you have your carpets cleaned, their steam cleaning equipment can’t reach old spills that may have soaked through the carpet backing and landed on or dried on top of the plastic Moisture Barrier


Carpet and padding side view - Is Moisture Barrier Padding a good choice?The job of a carpet cleaning professional is limited to cleaning the carpet surface fibers. They are trained to never to clean any deeper or beyond the carpet backing. To make it clear, they are not able to clean as deep as your padding.


Carpet cleaning professionals are trained to never over-wet your carpet. If a carpet cleaning person were to soak your carpet through the carpet backing and into your carpet padding, your carpet would take way too long to dry. That could cause permanent damage to your carpet backing. It can cause wrinkles and waves. It can even cause mold and mildew to form under your carpet and under your pad. 

1. Moisture Barrier Padding In Basements

Some homeowners have a serious moisture problem in their basement and might think that a Moisture Barrier Padding will be beneficial by preventing moisture from coming up through the pad and carpet. 

Unfortunately, because concrete is porous it can allow moisture to evaporate upward.  A moisture barrier pad can trap moisture under the pad and can promote the growth of mold and mildew, potentially causing a hidden health hazard. 

In basements, it is better to use a padding that can breathe. That way, if any moisture is under the pad it can evaporate up any away and lessen the chance for mold and mildew to develop.

2. Moisture Barrier Padding For Pet Urine Accidents

Some homeowners think that a moisture barrier pad will help with pet urine problems, perhaps making it easier to clean up the accident and reduce urine odors. This is not true because any liquid that soaks through the carpet backing will spread out on top surface of the moisture barrier padding.

While the viewable wet spot you see on top of the carpet may appear to be just 2 inches in diameter. Under the carpet it could easily spread out to be 8 to 12 inches in diameter or more. The liquid is now stuck on the top surface of the moisture barrier padding just below the carpet backing.


Carpet cleaning equipment is not designed to suck up spills that soak through the carpet backing. 

Liquids that soak through the carpet backing will spread out and dry on the surface of a moisture barrier padding. This makes the pet accident or spill much more difficult to clean up since the size and scope of the accident can be misleading.

Once pet urine dries on top of the padding, the odor will become more evident as foot traffic and regular vacuuming will continue to disturb and reactivate the affected area. 

Every time you steam clean your carpets, the steam can “reactivate” any dried urine on top of the pad. Since some pets tend to have accidents in the same spot over and over again the problem becomes magnified and compounded. This is why I see no benefit in using a moisture barrier pad, for homeowners seeking to alleviate a pet urine problem. 

3. Moisture Barrier Pad Over Hardwood Floors

Homeowners often install carpet and pad over beautiful hardwood floors. Some folks think that using a moisture barrier pad will help protect their beautiful hardwood floors from being ruined from any potential liquid spills.

Prolonged exposure to moisture can cause serious damage to hardwood floors. Potted plants and pet accidents are the moist common cause of damage to hardwood floors when a moisture barrier pad is used.

Some say that if the padding seams are sealed with duct tape, that liquids will not be able to soak through. If any spills fall near a compromised pad seams or near the outer edge, any spill will get underneath the pad and become trapped underneath. If not able to evaporate quickly, damage to the hardwood floors could be substantial over time.

From all my experience in the flooring business I’ve learned one thing for sure; that water (or any spill) will somehow find a way to soak through any moisture barrier and can cause significant damage, especially if trapped  without any way to evaporate off. 

For homes with hardwood floors, using a pad without a moisture barrier would be my suggestion. Most minor liquid spills would be able to evaporate and dry within a short period of time before causing serious damage to the hardwoods below.

Beyond the Moisture Barrier Pad

In the end, some folks spend a significant amount of money on specialty pads hoping for the best and end up not getting the results or benefits they expect. I don’t generally recommend using any specialty pads because overall I think they are overpriced, have limited benefits and may cause more problems then they solve.


Some carpet manufacturers are offering a warranty extension if you buy their specialty padding. 

Most homeowners never file a carpet warranty claim. If you consider the increased price of the pad against the limited benefits from an extended carpet warranty, you might find that it is not worth the added expense. 

I don’t recommend buying any padding that will increase your new carpet warranty limits unless you have money to burn.

Any good quality Rebond type padding with sufficient density (minimum 6 to 8 pound density) can likely do the job just fine and save you money.

Selecting the right carpet, choosing the right pad, getting qualified installation and buying from a reputable dealer are the four most critical factors in buying new carpet. Read through my website for more information and insight about how to buy new carpet wisely!

The Carpet Professor Says…

If you suspect you have a water leak or moisture problem in your basement you need to fix the problem before you install any flooring product. There are many simple ways for you to test your concrete basement for moisture problems.

I suggest you research this further to make sure your basement does not have any moisture problems before you install any flooring products.

Read more about Carpet Padding  


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