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For the uninitiated, the January/February installment of "You Make the Call!" explored a residential double-glue carpet installation of an expensive, imported carpet in which bubbles began appearing in the traffic lanes one month after the project was complete(photo 1).

The bubbles were steamed and rolled down, and they have yet to reappear. A year later, however, the problem began appearing elsewhere.

As I stated before, the installation professional responsible for the project is a CFI-certified master installer I happen to know quite well, and one who takes pride in the work he does. Because this project involved an imported product, the installer requested the mill's recommended installation instructions prior to starting the job.

The mill recommended a premium multi-purpose adhesive be used to secure the carpet to the pad. As discussed in the earlier article, the bubbles were discovered to be forming in the carpet, not the pad.

The following is a summation of information gleaned from the data specification sheet and an unused remnant of the carpet submitted to a laboratory for material analysis of the backing system's composition. The material was dissected and visually evaluated (photos 2 and 3).

The backing/coating is a textile, non-woven polypropylene with hot-melt polyethylene adhesive. The secondary backing appears to be a stitched, fleece-like material adhered to the primary backing with the hot-melt polyethylene. The pile is comprised of 100 percent polyamid.

This carpet is not usually used for a double-stick install. It is normally found in stretch-in installs or direct-glue applications. Based on the composition of the materials used to make this carpet, a multi-purpose adhesive should work.

Well, not all multi-purpose adhesives are created equal. The adhesive used on this job was not a solvent-free, water-based latex product. This particular adhesive contains 5 percent petroleum distillates, or solvents. The primary backing of this carpet contains a hot-melt polyethylene adhesive (e.g. plastic soda bottles).

Are things starting to gel yet? Now what do you think? You Make the Call!

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You have probably surmised that a chemical reaction took place between the solvents in the multi-purpose adhesive and the adhesive found in the carpet backing. This reaction caused the primary backing to be compromised, leading to the dimensional instability that ultimately resulted in the bubbles.

What about the seam sealer? If it had been a solvent-based product, what do you think would have happened at the seam? In this case, the seams and the wall base were installed with solvent-free adhesives, and as a result no bubbles or bonding issues developed.

It is important to remember that, when working with a product you are unfamiliar with, creating a paper trail detailing your attempts to complete the work properly is crucial. If you are instructed to work in a certain manner, document it. Then, if that approach proves faulty, you will be able to demonstrate both your diligence and from what source the order came.

I would like to thank CFI master installer and FCI columnist Michael Hetts for going above and beyond the call of duty to assist a fellow installer; be assured the effort was much appreciated. Additionally, many thanks to Benny Wood at Advanced Adhesive Technologies for taking the time and patience to explain to this layman the laboratory results and chemical terminology.

Editor's note: Due to the high volume of calls and letters regarding the problem discussed in the January/February 2002 article "Bubble, Bubble, Toil and Trouble," columnist Bill Baxley agreed to revisit and expand on the subject in this installment of "You Make the Call!"