By Terry Weinheimer, The Weinheimer Group inc
Carpet delamination or separation of the carpets primary and secondary backing is one of the most misunderstood complaints in the carpet industry. Carpet delamination claims usually start out as concerns with seam appearance, a buckled or rippled carpet, fraying at room edges or fraying next to hardwood, ceramic, laminate or other hard surface floor.
The installer is called out to look at the carpet. Upon turning back a portion of carpet the installer is concerned with what appears to be a light spread of latex on the back of the carpet. Perhaps a chalky white powder is coming from the carpet back. While these may be real carpet delamination concerns, more often than not this is not a manufacturing defect and the consumer or “carpet professional” is not seeing a true carpet delamination problem.
In this article I will discuss some of the more common concerns seen by The Weinheimer Group and other expert inspectors when investigating carpet delamination claims. I will also offer some tips for identifying carpet delamination and lamination problems.
Carpet Delamination: Top 10 Alarms
1.Carpet is fraying and looking ragged next to the wall and at transitions.
2.Seams fraying and opening on cut pile carpet.
3.Yarn pulling out at seams on looped pile carpet.
4.The edge of a new roll of carpet shows backing separation.
5.Carpet backing has what appears to be skips in the latex.
6.Carpet backing appears to have a light coat of latex in some areas.
7.Chalky powder coming from the back of the carpet.
8.Ripples developed after the carpet was installed.
9.The back of the carpet appears to separate easily when pulled.
10.The bonding agent on the back of the carpet is brittle or crumbly.
To understand carpet delamination it is helpful to have a basic understanding of carpet manufacturing especially as it relates to the back of a carpet.
Simplified Explanation of Carpet Backing Manufacturing Step
1)Face yarn may be of a natural or synthetic material the most common being nylon, polyester and olefin.
2) Primary backing is most commonly a pre-formed, tear resistant woven or non-woven polypropylene fabric. The yarn is stitched into this material in a process called tufting. As the yarn is sewn into the primary back it is either left as a loop of yarn so that a looped pile carpet is created or a blade cuts the loop to create a cut pile carpet. Sometimes only some of the loops are cut to create a cut and loop design. Beside providing a fabric to sew the yarn into, the primary back contributes to the dimensional stability of the finished carpet.
3) Bonding agent: The typical bonding agent is styrene-butadiene-rubber (SBR) latex adhesive. The adhesive secures the yarn that has been tufted into the primary back and binds the primary and secondary back together. On a tufted carpet the bonding agent is usually the only way that the yarn is locked into place.
4) Secondary backing: While some natural fabrics are still used, most commonly the secondary backing is a woven or non-woven polypropylene fabric. This second backing is laminated to the primary backing using a bonding agent. The secondary backing adds dimensional stability to the carpet and makes it slide easier as the carpet is stretched during installation.
Carpet adhesive contains economical filler, most commonly calcium carbonate (marble dust), the same material used in plaster for swimming pools and buildings. The calcium carbonate does not contribute to the properties of the carpet. The filler is used to lower cost and increase viscosity.
During manufacturing and just prior to the application of the secondary back to the primary back the bonding mixture is heated and applied to the primary back to better bind the yarn. Frequently a precoat of SBR latex is applied to better lock in the yarn. During the application of the secondary backing pressure is added to help bond the backings. The carpet typically passes through an oven that dries and cures the latex.
Carpet Delamination What Causes it?
When carpet is manufactured it has a raw edge. We all understand that if a garment fabric has had the selvage cut off it needs to be hemmed or have a serged edge applied to keep it from fraying. The raw edge of a carpet backing fabric is no different in the sense that if it is not protected it to will fray. To protect that raw edge the carpet must be fully tucked between the tack strip and the wall so that the threads from the raw edge of the back will not work to the surface.
As with the backing around the walls, threads from the raw edges of the backing when not adequately tucked or protected will work to the surface. As you walk across these transitions or vacuum the carpet in these areas the back of the carpet can be separated. When it is difficult to protect the edge it is often advisable to use an adhesive along the raw edge to seal it.
The seam is looking ragged, tufts start pulling out, and perhaps the backing of the carpet is slightly separated in random areas. Remember, that carpet has a raw edge. Most of you have seen a shirt, dress or jacket pull apart where it was not had its raw edges properly hemmed or serged at a seam. The same is true with carpet and therefore most carpet manufacturers and the Carpet and Rug Institute state that prior to seaming a bead of seam adhesive is to be used on the cut edges of the backing. Unfortunately many installers will skip this process as it is time consuming and they just hope they will not get stuck with the problem when it occurs.
Remember that the loops are just sewn into the backing on a tufted carpet.These loops are usually locked in only by the adhesive that is applied during manufacturing. If you pull on a loop you can pull out a row of yarn and potentially the length of the installed panel. When a row of loops is pulled out the backing becomes frayed making it easier for the next row of loops to release. It is extremely important to apply a sealer to the raw edge of a looped carpet at the time of seaming. If this process is skipped or the sealer is not applied correctly a row of yarn can be pulled out.
When an installer unrolls a new roll of carpet for installation he may notice areas where the edge of the carpet backing is not laminated. The installer and consumer see these separated edges and they may think the carpet is delaminating. In reality, when carpet is manufactured the bonding agent may not coat the outside edge adequately and this is usually not a defect. During seaming the edges are to be cut back far enough (usually 1 – 2 inches) to provide a secure edge. If a carpet back is separated too far to properly trim the edge, the carpet should not be installed and the manufacturer should be contacted.
If you have what appears to be a skip, try lifting with an awl. If the secondary back can be lifted away from the primary back it is obviously separated. An occasional short random skip should not be a problem and for peace of mind, coating it with a bit of seam adhesive will assure you that it adequately secured. If these skips are severe the installer should not install the carpet and the manufacturer should be contacted. It is also important that a carpets back should not be bent for rolling or stepped on when turned back during cutting or installation. Folding and stepping on a bent back may break the bond and create what appears to be a skip.
This may be higher quality latex with less filler. Perhaps the bonding agent is not latex and instead a different bonding agent, perhaps poly vinyl chloride (PVC). With many bonding products the backing of the carpet will be harder to separate even when the coating appears light. If the backing appears to separate as easily as the peel on a ripe banana it may be a true delamination concern.
A chalky powder may be seen on the floor below scraps of a recently installed carpet. A corner of the carpet is lifted and more of this chalky powder is seen on the top of the pad (cushion) where it has fallen from the back of the carpet. When the back of the carpet is bent or shook more of this powder falls out. The first reaction is that the adhesive is failing and the backing is going to come off.
Powder coming from the back does not mean the carpet is going to delaminate. Remember that the bonding agent has filler in it that is made of marble dust the same ingredient in plaster. With high filler content some of this powder is going to come out. Unless the delamination pull test indicates low lamination strength or the backing is falling off without external help this is rarely a delamination problem.
Some times ripples or wrinkles develop after a carpet has been installed. Some times the carpet is “restretched” and new ripples occur within days, weeks or months. When this occurs installers and retailers often believe that there must be a delamination or dimensional stability problem with the carpet.
When a new carpet is installed it should be power stretched. Even if Hercules is installing the carpet a knee kicker is not a power stretcher. A spike on the end of a pole attached to a power stretcher head is not a power stretcher. When you see poles (pipes) stretched out across the room and attached to a power stretcher head, this is the typical, proper way of power stretching. There are circumstances where it may be necessary to use other forms of stretching, especially in very large or extremely small areas.
When ripples develop and the carpet is restretched, just kicking out or stretching out the obvious wrinkles is not going to take care of the problem. A proper restretch includes removing the furniture from the rooms, lifting the carpet at all edges and power stretching all of the carpet in both width and length. When necessary some seams will need to be reworked. When ripples recur and the carpet has not been properly and fully restretched there is little basis for this being a manufacturing problem.
As we discussed, most carpets have two backs on them called a primary back and secondary back. Many installers mistakenly believe that if they can easily separate the secondary back from the primary back the carpet must be defective. Again let me remind you that the secondary back is there to add dimensional stability. It does not require a high bond between the primary and secondary back for the backing system to be doing its job. The fact is that the FHA standard for carpet lamination strength is only 2.5 pounds. As a method of comparison I performed a test on an orange and found that it required a minimum of 4 pounds pressure to remove the peel.
As we discussed earlier the responsibility of the bonding agent is to lock the yarn into the primary back of the carpet and provide sufficient lamination to hold the secondary backing in place. At times it may require more than the minimum 2.5 pounds of pull to separate the primary and secondary backing and yet the latex appears hard, brittle or crumbly. A hard, stiff backing may indicate a possible dimensional stability problem even when the latex is not brittle or crumbly. Hard or even soft or sparse combined with brittle or crumbly is an indicator of a potential delamination problem even when one has not occurred. Usually testing will be required to confirm a problem.
Identifying the Causes of Delamination
If the backing of a carpet is just falling off this is a delamination problem. This may be manufacturer related delamination due to breakdown of the latex or other bonding agent that was used to laminate the primary and secondary back. It is important to understand that water damage such as that from a large spill or leaking plumbing, improper wet cleaning coupled with slow drying and also urine can also cause the breakdown of the latex bonding agent.
Delamination is usually first seen as ripples or seam separation. If ripples are seen, it is usually fairly easy for an experienced person to determine from the surface if the carpet is loose or the problem is delamination. Check for delamination by pushing your hands toward the ripples and watch how these wrinkles move. If the ripple suddenly stop this is typically localized delamination. If the ripples continue to move all the way across the room lift the edge of the carpet and if delaminated it will be visible. If you do not see delamination you are pushing the ripples in a loose carpet. If you are unsure of what you have found the best way to be sure is to turn the carpet back and check it visually.
When is a delamination concern a true manufacturing problem?
Manufacturing delamination will usually be seen as the secondary back literally falling off. Frequent causes of delamination are inadequate latex coating and excessive filler. If you have to pull on the backing to remove it this is usually not delamination. The FHA standard for laminate strength on carpet is only 2.5 pounds per inch so it does not take a lot of pull to remove the secondary backing. Hard, crumbly latex that easily rubs or breaks off the carpets back even when the laminate strength is presently in excess of the 2.5 pound minimum is a good indicator of a manufacturing problem. Remember that the secondary backings major job is to provide dimensional stability and ease the stretching of the carpet across the pad.
If the back of the carpet is falling off and the back is stained, or tacky feeling the delamination was caused by water damage, improper cleaning or urine damage which are site and maintenance related problems and not manufacturing.
If you believe manufacturing to be the problem or a contributor you should have the carpet looked at by a professional carpet inspector who will be able to make test or send a specimen out for a test. The manufacturer may also require a specimen of uninstalled carpet for testing of their own. If a remnant is not available cut out a piece from a closet or other area that has not experienced foot traffic or preferably not been cleaned.
Although there are no established industry wide definitions for delamination, for the purpose of this document the following term is specified.
Delamination: a condition in which the secondary back has separated from the primary back.
Seam Delamination: a condition where the secondary back has separated from the primary back along the seam edge. May first be identified as fraying and loss of tufts at the seam.
Large area delamination: a condition resulting from the breakdown of the latex or other agent used to bond the primary and secondary backs
Latex: A water emulsion of synthetic rubber, natural rubber, or other polymer. In carpet, latex is used for laminating secondary backings to tufted carpet, back coating carpet and rugs, and for manufacturing formed cushion. Almost all carpet latex consists of styrene-butadiene synthetic rubber (SBR) compounded with large quantities of powder fillers. The later are most often whiting, which is calcium carbonate. Latex is the raw material from which rubber is made.