FOAM CUSHION MATERIAL
The Purpose of this webpage is to educate you about foam cushion materials which are used in
furniture. There are many different grades of foam that are available to the Upholsterer. This
webpage will explain the rating standards for foam material so that you will have a better
understanding of what makes a particular foam suitable for various applications. There are not
necessarily "good" foams and "bad" foams. There are, however, good and bad uses for each
particular type of foam which determines your level of satisfaction and comfort with your
DO I NEED TO REPLACE MY FOAM?
If your foam cushion material is older than about 10 years, or if it is
beginning to have a "rounded" front edge, or if the seat foam doesn't offer
you the support you need to feel comforatable, then you are probably ready for new foam.
Foam production technology has made some very significant advances in the past decade.
Foams of varying densities and ILD ratings are now produced which offer the Upholsterer an
opportunity to select a specific type of foam based upon its intended use. Foam is rated
according to various performance tests. The results of these tests allow an Upholsterer to know
how the foam will "feel" and in what ways the specific foam may be used.
I mentioned the "rounded" front edge as a clue to the need for new foam. This effect occurs
over time because you tend to use the front of your cushion to a greater degree than the rest of
the cushion. As a result, that portion of your cushion becomes worn or compressed faster than
the rest of the cushion. Some Upholsterers will use their steamers to restore the foam to its
original shape but this is only a temporary fix and the foam will soon loose its shape again.
Another cause for this condition is that the foam never was the proper density to be used as
seating foam and as a result it has lost its shape in a relatively short period of time.
WHAT MAKES A GOOD FOAM?
There are three performance tests that are of primary concern in evaluating the suitability of
foam. The first concern is if the foam is rated as HIGH RESILIENT (HR). The next concern
is the DENSITY rating of the foam. And finally, the INDENTATION LOAD DEFLECTION (ILD)
rating is of equal importance as the foam's density rating.
HIGH RESILIENT (HR) foam is what you might think it is. It is a foam material that is
produced to offer a longer useful life than non-HR foam. HR foam is often also rated as fire
resistant (FR). Tell your Upholsterer that you are concerned about fire safety and long life of
your new foam and ask him to verify that your new foam is rated both HR and FR.
If you are reupholstering furniture which will be used in a public setting, most States have
Furniture Flamibility Laws that will require you to use HR-FR foam materials.
The DENSITY rating of furniture foam is expressed as a two digit number which may range
from 18-35. Actually, there is a decimal between the two numbers which makes the density rating
of the #18 foam a 1.8 foam. In the production of foam, there are two basic ingredients which
are the urethane chemical that is the foam, and air. The more chemical that exists in the foam
material, the higher its density rating will be. In the above example, the 1.8 rating means that
there is 1.8 pounds of chemical in each cubic foot of foam material. A cubic foot is equal to
an area that is 12" x 12" x 12". This particular foam would be rather low in density and would
not be a good material to use in seat cushions. It would, however, be suitable for back cushions
as back cushions do not need to support your body weight as seat cushions do. Most people prefer
the comfort of a low density foam in their back cushions for the soft feel that allows them to
"nest" into their chair.
The next rating of concern is the INDENTATION LOAD DEFLECTION (ILD) rating. This is a
measure of how much pressure it takes to compress the foam 25% of its thickness. For instance,
if your seat cushion is 4" thick and has an ILD rating of 33, it would take 33 pounds of
pressure to condense the foam to a thickness of 3". In normal operations, most shops prefer to
use a foam with a density rating of 3.1 and an ILD rating of 33 for sofa and chair cushions.
They'll usually use a back cushion foam which is a 2.4 density with an ILD rating of 18. This
foam material produces a medium-firm back cushion. Where a softer back cushion is desired
the 1.8 density/ 11 lb. ILD foam material may be substituted.
On dining room chairs, where the thickness of the foam is generally lower (1-2"), it would
be recommended to use a foam with a density rating of 2.8 and an ILD rating of 41 to compensate
for the reduced foam thickness. Where some reupholstery clients prefer the softer feel of the
33 lb. foam for dining seats, It is usually recommend increasing the foam thickness by 1/2" if
the chair style lends itself to that option.
Below is a chart which describes some of the different foam materials. Notice how an entirely
different ILD rating can be produced using a density rating in the 2.7-2.8 range. This should
illustrate the importance of the ILD rating in selecting a suitable foam for your needs. A
high density foam is not necessarily the proper firmness.
You will note that the ILD ratings of the foam materials in the chart range up to 61 lbs. While
these very firm foam materials are available and have their specific and appropriate uses I
would never recommend the use of any foam material higher than a 41 lb ILD rating for seat
cushions. The 50 and 61 lb ILD foam materials may be used for such applications as kneelers
or fitness equipment pads where the foam thickness is limited to 1-2" and the higher ILD rating
is necessary to compensate for the limited thickness of the foam.
||Soft back cushion, envelope feather/down cushion
||Firm back cushions, XX-Exta soft seating
||Extra firm back cushions, Soft seating
||Medium soft seating
||Medium seating.(Exceeds industry standards)
||Medium firm seating
||Medium firm seating
||Firm (2" Dining chairs)
||Extra firm seating
||Extra firm seating
WHAT ABOUT "CUSHION WRAPS"
Cushion wraps are a layer of material that is installed between the foam material and the fabric
cover. A commonly used cushion wrap material is DACRON. It is commonly recommended to use as
cushion wrap and is further recommended that the dacron material be laminated to the foam using
special foam glues.
The purpose of the dacron wrap is to soften the sharp edges of the foam to give it a more soft
appearance. The dacron wrap also helps to protect your fabric in the event of a liquid spill by
allowing the liquid to pass through your fabric and the dacron and settle in the foam. While the
spill may keep your foam wet for several days, there will be a barrier between your foam and
your fabric which will allow your fabric to dry out rather than continue to soak up the wetness
from your foam. Even a dry spill,such as dirt, will have less of a soiling effect on your fabric
with a dacron wrap as the dirt will pass through the dacron to some extent and not be ground
into your fabric as much. Another advantage of a dacron wrap is that some foams and fabric
backings are somewhat abrasive. Each time you get into, or out of, your chair the fabric and
foam rub together to some extent. The dacron wrap will eliminate this abrasive action and
extend the life of your fabric and/or your foam. The dacron wrap should be laminated to the foam
to prevent the dacron from moving and bunching up inside of your cushion cover. A laminated
dacron wrap will likely increase the cost of your foam cushions, but should be considered a good