Here’s a situation that has generated several complaints lately and is, it seems all of a sudden, a real concern for commercial carpet dealers, manufacturers and general contractors. What I’m talking about is the use of self-adhering, clear plastic carpet protective material, placed on top of carpet after installation to prevent soiling and other influences from affecting the carpet surface. The concept of this product is certainly a good one – a light weight, self-adhering, clear plastic protective film that covers the carpet surface to protect it from soil and other contamination prior to the end user occupying the finished space. We’ll look at four specific cases where this material caused a problem.
In one of the cases the general contractor had put down the plastic covering in a large office environment on several floors. The plastic was put in place, on top of the carpet shortly after the installation. When the plastic was removed they noticed the carpet had discolored dramatically. All over the carpet were streaks of discoloration and mottling, like irregularly shaped lines. The general contractor was in a pickle because they were the ones who were responsible for putting the plastic on the carpet. The dilemma was that they had created the problem through their action and now needed to determine what exactly happened and what, if anything, they could do to correct the condition. Unfortunately there was nothing they could do to reverse the damage to the carpet. What happened?
What happened was the plastic was placed on the carpet right after installation, before the adhesive used to glue the carpet to the substrate was fully dried and cured. The plastic placed onto the carpet surface to protect it actually damaged it. Trapped moisture from the drying adhesive could not escape through the carpet. The trapped moisture destabilized the dye, weakening it and caused it to migrate and distort the coloration in the carpet. This disturbance and actual degradation of the dye caused the discoloration of the carpet. Once the dyes are changed or migrate in the carpet it is impossible to reverse this process. The moisture trapped during the curing of the adhesive created an environment in the carpet that forever changed its appearance.
Had the general contractor waited for the adhesive to cure, which could have taken as much as 48 hours or more depending on conditions, he would not have encountered the irreversible problem he created. In a conscientious effort to protect the carpet and keep the construction work going he destroyed the carpet and was forced to replace it – never an inexpensive undertaking.
The manufacturers instructions on the protective plastic material state that it should not be placed on the surface of the carpet until the adhesive used to glue the carpet in place has cured and dried. They make this statement because they have experienced this problem before and they have been blamed for the carpet being damaged. To prevent this from happening again, and taking the blame, they wisely inform the user of the product not to employ it until the adhesive dries.
There are other forms of moisture that can affect the carpet if the plastic covering is left on too long. The moisture in the air, in the form of high humidity, can be enough to cause a problem with the color of the carpet, especially if the carpet is nylon or wool, both of which will absorb moisture. Nylon will absorb about 4 to 5 percent of its weight in moisture and wool as much as 27 percent. If the moisture is not allowed to evaporate from the carpet because it is trapped, it can and will cause a reaction in the color of the carpet. And here’s a fact that should really scare you, even if the carpet is a solution dyed nylon, the color can be affected by putting plastic covering over it while there is moisture present in or under the carpet.
Where would the moisture come from under the carpet if not from the adhesive used to install it? From the substrate, of course, in the form of moisture vapor emission, which when trapped while trying to pass through the carpet to escape, would wreck havoc on the carpet. Now two things would have to be working in conjunction in this type of a situation for this to happen. The substrate would have to be volatizing a high volume of moisture vapor after the carpet was installed and the plastic would have to be on the carpet for an extended period of time, like a week or more for example. Even so, just a few days might be enough to cause a change in the carpet color if there was enough moisture trapped in the carpet.
Another big problem that can occur from putting self stick protective plastic covering on the carpet is adhesive residue being transferred onto the face of the carpet. This light, sticky residue will attract soil to the carpet like a magnet causing a light carpet to turn black and a dark carpet to get darker. Here’s two cases where this happened, one having made the Bernardsville, New York newspaper on June 24, 2004.
A new $4.5 million municipal building was constructed in Bedminster Township, New York and scheduled to open on June 29,2004. The problem preventing the opening was caused by the plastic covering designed to protect the carpet from soiling during construction. When the plastic was removed it seemed the carpet had turned color. At first officials thought a chemical in the adhesive used to glue the carpet down had caused the discoloration. However, upon further investigation it appeared that the adhesive from the plastic had penetrated into the carpet causing dirt and dust to stick fast. “It turned the carpets orange – just like the color of the soil in Bedminster,” the mayor said. The carpet manufacturer offered to provide the township with a chemical cleaning solvent to get rid of both the adhesive and the dirt. If the carpet won’t come clean it will have to be replaced, which would involve waiting about 8 weeks for new carpet to be produced. The general contractor put the plastic on the carpet and has accepted full responsibility for the damage and pledged to replace it if the cleaning did not work. All of this has delayed the scheduled move-in to the new facilities. None of this is the carpet manufacturers or carpet contractors responsibility.
In a related situation, a general contractor places the plastic covering on the light colored carpeting in the corridors and offices of two renovated buildings of a single client. In one building the carpet looks fine when the plastic is removed, and it stays that way. In the other building the carpets on every floor got black after the plastic was removed and in addition to that, everything that had been placed on the plastic was showing up on the carpet surface. This included the base of plastic buckets, the cleats from the drywall finishers’ stilts, panels from modular furniture, etc. All of the outlines of these things could be seen clearly on the surface of the carpet. Why? Because the adhesive from the backing of the plastic covering had been pushed into the carpet by the concentrated weight placed upon it. This caused a heavy adhesive residue in these areas, which allowed soil, adhering to these areas, to reveal where pressure from the object placed on the plastic came in contact with the carpet. Also visible was the outline of the plastic edges. Again we asked the question why? If one building with the same carpet was fine why was the other one such a mess?
We conducted a series of tests to determine the answer to the questions. We obtained a roll of the plastic left over from the job as well as a large scrap of new carpet and a section of the affected installed carpet, cut from one of the corridors. The plastic was applied to a section of the new carpet and then inserted in a Hexapod test, which subjects the carpet to the pressure and motion of a twelve pound hexapod shaped object rolling around in a drum. Another piece of the carpet was tested the same way, the plastic removed and then tested again with an accelerated soiling test. The plastic left a residue on the surface of the carpet when subjected to the hexapod test, indicating some adhesive transferred off the plastic and onto the carpet surface. The section of carpet tested with the plastic on, and then removed, and then tested with the accelerated soiling test, resulted in the carpet turning black with dirt. The soiled section was then cleaned and tested a second time to determine if there was still a residue, which would attract soil and there was. This sample was not as dirty when removed from the test because we had succeeded in cleaning a lot of the residue off the carpet the first time. But there was still a light adhesive residue remaining, which continued to attract soil. We used water based soil cutting agents, a water based cleaner with hot water extraction and then alcohol, none of which completely removed all of the residue. A pure solvent could not be used in volume to clean the carpet, even though it would work, because it would also compromise the integrity of the carpet backing. The carpet still got dirty again after all of this, not nearly as bad but noticeably due to the light color it was. Our client in this case replicated our cleaning procedures on sight, with a little more aggressive action, without complete and acceptable success – they had to replace the affected carpet. But did we answer why one building was affected and not the other? Here’s our answer to that question. The adhesive on the plastic used in the affected building may have been heavier and therefore left a residue. The temperature and humidity in the space could have been higher causing the adhesive to weaken and soften and transfer off. There could have been more moisture on the surface of the affected carpet due to humidity in the air or moisture vapor emission from the concrete beneath the carpet causing the pressure sensitive adhesive to weaken. Remember these were two different buildings, next to each other on the same block but separate structures. The manufacturer of the carpet used in these two buildings, wisely, and I’m sure from a bad experience, had a notice in bold letters on their spec sheet that plastic covering was not to be used on their carpet products. This absolves them from any liability, though they did offer help in this case with the cleaning.
The last case involves a woven wool/nylon blend carpet, 80% wool and 20% nylon. The plastic covering had been placed on the carpet the same as in the other cases. After the plastic had been removed and the carpet subjected to traffic it was noticed that the face fibers were sticking together. The residue from the plastic covering could be felt on the surface of the carpet. Because the natural wool will hold the adhesive residue more aggressively, and did, the fibers in the carpet were sticking together. Again, the general contractor was responsible for this problem because they put the plastic down but they looked to the carpet contractor and manufacturer for answers.
The reason the plastic covering is used is because it is strong, self sticking and easy. The reasons it can create problems, you just read. It can leave a residue that will attract soil and be near impossible to remove and even if it can, the cost to do so is considerable because it is a labor-intensive task. It can cause the color in the carpet to migrate if moisture is trapped, this the manufacturer of the product warns against.
As a flooring contractor, general contractor, manufacturer or other party responsible for the well being of the carpet, you should state that the carpet should be protected and how. The safest way to protect the carpet from the conditions you just read is with brown kraft paper, although it can and does rip and travel or better yet use Masonite boards. Any adhesive material on the top of the carpet is going to leave at least some residue. You can’t control the conditions in the air, under the carpet or in the work-space that could create the problems we’ve discussed in this issue.
Because the problems with self-adhering plastic coverings have been such a concern lately it is my opinion that they should only be used if you can insure there won’t be a problem from the product or from some other influence, especially where construction work is still on-going. There should be a mention on spec sheets, as some manufacturers have already done, that this product could cause a problem as a result of its use, and that you will not be responsible for any damages. This should also go for the flooring contractor and any other contractor responsible in whole or part for protecting the carpet. The use of self-stick plastic covering has adversely affected carpet, causing costly cleaning and/or replacements and gives carpet a black eye. The carpet has nothing to do with the problem other than the fact that it is the material being affected. Whoever causes damage to the carpet should be responsible for repairing, cleaning or replacing it. I’m not saying not to use this material but you have to know what can happen in some cases if you do.
Author – Lewis G. Migliore – The Commercial Flooring Report
LGM and Associates – The Floorcovering Experts