Inspection Safari: Carpet Stain Blocker Failure

carpet stain blocker

Sometimes when I receive an inspection request, the stated reason and the actual complaint are different. Today’s Inspection Safari is a perfect example of such a complaint.

A major carpet mill asked me to inspect a carpet for “stain blocker failure.” Most of today’s carpets are made using some type of stain resistant technology. So a permanent stain is often covered by the carpet warranty. My job would be to see if this stain was something that might be a “warrantied defect.”

I called the homeowner to schedule an appointment and asked him if there was a problem with a stained carpet. He said, “Yes, AND the carpet is coming apart.” He explained that the spot had been professionally cleaned five times. The last time it was cleaned, the technician “was aggressive” with the cleaning and the carpet delaminated (separated)! So now I also had to determine the structural integrity of the carpet.

When I arrived at the home, I saw that the reoccurring pet urine stain was on top of a carpet seam. The top layer of the carpet (primary) had separated on both sides of the seam, but the bottom layer (secondary) was still attached to the seaming tape. First, I had to verify the cause of the stain. Then I had to find out why the carpet had separated. Was the delimitation caused by the urine/ cleaning, or was there an underlying weakness in the carpet itself?

I have reproduced the body of my inspection report here. It explains my methods and conclusions:

Overall, the appearance of the carpet is excellent. Tufts are well twisted in the high usage areas. The carpet pile looks clean and fluffy.

A dark gray area, 8” X 14”, is found along an unsealed seam in the living room walkway near the slider. The primary backing has separated from the secondary backing up to 3” on each side of the seam. The secondary backing is still firmly attached to the seaming tape. The spot smells from urine. I tested pH at “7”/ neutral. I shined a 5X ultraviolet lighted magnifier over the affected area. The face fibers did not glow but the secondary backing glowed blue, indicating the presence of urine. The UV light also did not indicate any seam sealer between the primary and secondary backings of the cut edges.

I checked two pieces of attic scrap. Primary/ secondary lamination is excellent. The backing is soft and flexible. I lightly misted a neutral spotting solution onto a small portion of the affected area. After gently tamping in the solution with a soft brush, I lightly blotted the treated area with a white terry cloth towel. Soil immediately transferred to the towel and the area lightened noticeably, indicating that the stain blocker is working effectively.

I pulled up the carpet at the bedroom end of the hallway to check the pad type. the corner that I pulled up was urine-soaked. The tack strip pins were rusty from the moisture.


The CRI (Carpet and Rug Institute) Carpet Installation Standards 2011 states:
“CAUTION: Failure to properly prepare seam edges often results in: • edge ravel • edge delamination • tuft loss • seam separation • safety concerns”

The Mohawk Warranty states:
Improper Cleaning and Maintenance or Inadequate Care
These Mohawk warranties do not cover damage to your carpet caused by improper cleaning, improper maintenance or cleaning materials or inadequate care.

Improper Installation
These Mohawk warranties do not cover damage to your carpet caused by improper installation. Examples include, but are not limited to, wrinkling due to insufficient stretch, loss of tufts due to improper seam sealing, and seam peaking.

These Mohawk warranties do not cover carpet odors.

Stain Reappearance (Wicking)
These Mohawk warranties do not cover reappearance of previously cleaned stains. If warranty conditions set forth in this brochure are met, stains that are saturated and result in wicking will release with additional re-cleaning.”

It is my opinion that the reoccurring stain is either due to wicking or re-contamination by the pets. The delamination is caused by a combination of urine contamination, overwetting by the cleaning technician, and lack of seam sealer.

Glenn Revere IICRC #113098

This tale shows you that things are not always as they appear. A stain might be a stain. Or it might be wicking. Or it might be a “revisit” by a pet. A delaminated carpet might be a badly made carpet. Or a badly made seam. Or “overly aggressive” cleaning. Or all of the above.

Stay tuned for more Inspection Safaris.


Who is Glenn Revere?

Glenn Revere has been a carpet expert since 1973. He’s a certified flooring inspector and the author of All About Carpets, the only book written to protect and inform you about your carpet choices, from carpet buying and carpet warranties to carpet care and maintenance. You can find him on Facebook, Google+ and Twitter.

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