Carpet Pads Insulating Underlayment

Carpet Pads / Cushions Insulating Underlayment

Carpet pads or cushions literally make or break a carpet. I must admit that I did not fully understand the importance of carpet cushion until I did the research for this column. Once it was explained to me, it made perfect sense. I'll try to do the same for you in this short space.

Carpet Backing

Carpets are simply thousands of threads or fibers that are held in place by a backing. The threads or pieces of fiber are sewn through the backing. If the backing flexes or bends too much, the fibers become loose. The same thing can happen if there is no flex to a carpet backing. The fibers can actually come out of the backing. If this happens, the carpet looks worn and it can actually fall apart.

Cushions are the Foundation

A carpet cushion works to absorb the impact of foot traffic on carpets. This keeps the fibers tightly bound into the backing. However, if you allow the backing to flex too much by using a thick pad, the backing can actually stretch or break allowing the carpet fibers to separate from the backing. You walk a fine line in order to preserve the carpet integrity.

Thinner is Better (Often)

It stands to reason that a thinner carpet cushion will flex less than a thicker cushion. If you want your new, expensive carpet to last in high traffic areas such as stairways, hallways, or other high volume traffic areas, select a thinner, denser cushion (no thicker than 3/8 inch). This will protect your carpet.

Carpets Over Concrete Slabs

The stimulus for this column and bulletin was based upon several letters I received from people whose houses sit on slabs. They complained about cold floors in the winter time. Upon researching the topic I found that you can insulate beneath a carpet quite effectively. Not only will the carpet cushions act as insulators, you can also install a fantastic recycled fiberboard insulation product.

The fiberboard insulation product is comprised of recycled newspaper. It is extremely dense and offers an R value of 1.2 for a 1/2 inch thickness. This means that if you install this fiberboard and then use a 1/2 inch prime urethane cushion, you can achieve an R-value of 3.3 beneath a carpet. That is an outstanding accomplishment. Cold carpeting or floors will be a thing of the past.

Sound Control

Carpet cushions and the above mentioned insulating board will also help control noise. This may be a consideration if a bedroom is over a family room. It may also be helpful in an office or light commercial environment. Carpet itself helps absorb the air borne sound waves. However, a cushion beneath a carpet will further absorb and dampen the vibrations which transmit noise to another room or space. If you are building a new home and are concerned with sound transmission between floors, you should pay close attention to the sound deadening properties of the insulation board coupled with a resilient cushion.

Selecting a Carpet Cushion

All too often homeowners pay little or no attention to their carpet cushion or pad. They let the sales person do this task. It can be a costly mistake. However, as you continue to read this bulletin, you will find it is not necessarily a simple decision.

The carpet cushion industry formed an association to help promote the benefits and importance of carpet cushion. They have some excellent literature which I suggest you read. One article in particular is a must. It is titled Benefits Of Carpet Cushion. It tells you exactly the minimum type and specifications of carpet cushion to select for each room of your house. I suggest you check this article and one titled Cushion Criteria on their website under Consumer Info.

Carpet Cushion Council
P.O. Box 546
Riverside, CT 06878
203-637-1312
www.carpetcushion.org

Insulating Fiberboard

As hard as I tried, I could only locate one manufacturer of carpet insulating fiberboard. That is not to say another is not out there. However, one New Jersey company specifically manufactures and markets a board for this purpose. They have great literature. The Carpet and Rug Institute is in the process of certifying this underlayment. Call the manufacturer and ask about ComfortBase.

Homasote Company
Box 7240
West Trenton, NJ 08628-0240
800-257-9491

Carpet Cushion Insulating Values

The following is a listing of the thermal performance of carpet cushions. You will notice a huge difference among different types. The values listed are R-values. R value is a measure of resistance to heat loss. To put the cushion values into perspective, ordinary fiberglass wall insulation has an R value of a little over 3 per inch - 11 for 3.5 thickness.

Data courtesy of the Carpet Cushion Council, P.O. Box 546, Riverside, Connecticut 06878, 203-637-1312 Send them a regular#10 self addressed stamped envelope and ask for free carpet cushion information!

Carpet Cushion Types / Descriptions

A huge majority of carpet cushions will fit into one of the below categories. As you might expect, there are different grades of material within each category. The higher grades are often used in commercial installations where foot traffic over carpet is extreme. Be sure to ask what will do best in your residential application. As with most things, higher cost often means better quality.

Fiber Carpet Cushions

Perhaps you have seen a fiber pad before. Possibly it was a natural fiber pad such as jute or animal hair. You can also purchase synthetic fiber cushions and ones that are resinated recycled textile fiber. These cushions tend to produce a firm foundation for the carpet. The grade of this type of cushion is measured by ounces of cushion per square yard.

Sponge Rubber Cushions

Sponge rubber cushions come in two basic types: flat or waffled. The flat cushions tend to be stiffer or more firm than the rippled or wavy cushions. Once again, the grade is measured in ounces of rubber per square yard.

Prime Urethane Foam Cushions

Now it gets confusing! You can purchase three types of prime urethane cushion: conventional prime, grafted prime, and densified prime cushion. The first two (conventional and grafted) are made by mixing chemicals to produce the urethane. There is a wide range available. They have different densities and different levels of firmness. You will have to consult with the carpet people to see what will work best for you.

Densified foam is a special cushion which can be made to certain specifications. If a carpet company needs a cushion with a specific density, this can happen using this material. Its grade is determined by foam density or weight of foam per cubic foot.

Bonded Foam Cushions

These are the types that most people are familiar with. Bonded foam cushions are multicolored in nature. Shredded pieces of urethane foam are fused together into a giant sheet. As with all of the other cushions, density is measured by weight per square yard of material.

Frothed Urethane Foam

These are commonly higher density foam cushions. Urethane is bonded to a non-woven sheet of material much like the foam backings you find on padded carpeting. They can give a nice, firm foundation for carpeting.

Carpet Cushion Buying Tips

The greater the traffic which will traverse the carpet, the thinner the cushion should be! Select a cushion no thicker than 3/8 inch. Purchase as much weight per square yard as you can afford.

Bedrooms, dens, and other low traffic rooms can have a thicker cushion. A 1/2 inch cushion will deliver high resiliency and protect the carpet if it has a high density.

Don't cut costs on the cushion or buy it because it looks nice. The cushion is the foundation of the entire system! Laying an expensive carpet over the top of a cheap cushion is nonsense. Don't be swayed by a salesperson. Ask about density, weight, etc. If the salesmen looks puzzled, go to another store!

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