Question: We were asked to remove roll crush on some wall to wall wool carpet. It has an Action Bac backing. We were given the criteria of truck mount or hand steaming by the manufacturer. We elected to use our truck mount at 250 psi.(machine was set at 300 psi). We wet the carpet and groomed the yarn with a brush rake, followed by a glide wand. The result was significantly less than a 100% correction.
Answer provided by Jeff Bishop, SCRT Technical Director: Typically roll crush, especially on wool carpet, results from shipping or storing carpet rolls with multiple separate carpet rolls stacked on top in a hot vehicle or warehouse.
Procedures for correcting roll crush are: to dry vacuum the carpet and identify precisely where the crush bands are located;
- using the hottest water you are able to generate at low pressure (150-200 psi), go over the banded areas twice using normal double application of block-stroking technique. Move slowly to enable the heat to swell the yarns, particularly during the second pass;
- a second technician should then groom the carpet immediately, standing the pile upright relative to the crushed pile lay direction.
In large areas this is the most practical technique. In smaller areas, a hand-held steam generator (carpet steamer or wallpaper steamer) can be used on the carpet crush bands followed immediately with grooming with a carpet brush (not a carpet groomer or comb).
The problem with using a truckmount for correcting roll crush is that the vacuum that follows hot-water injection instantly cools the pile so you loose the effect of heat in swelling the yarn even when followed by grooming. Regardless, when this technique is used, grooming the pile upright should occur immediately after the second stroking sequence. If you wait to groom after the whole room or area has been rinsed, the effect of heat is totally lost.
Response: The manufacturer's representative first accused the installer and then us of faulty work. He thought that we were overly aggressive with a steamer and left indentations from the machine used. Defined as “machine heat-pressure streaks.”
JB: If so, those can usually be eliminated by immediate grooming following moist-heat application, which is essential to stand the fiber upright, before it cools and especially before it dries.
Response: We did not use a steamer. We are meeting at the client's home on Monday to take a look at the carpet and to see what, if anything, can be done. The manufacturer will be bringing their repairman.The steamer I use for correcting roll crush is made by a major manufacturer of carpet installation tools.
Do you have any suggestions in general about reversing roll crush on this carpet? See above. How would your approach differ if this was a nylon carpet?
JB: No difference, however, synthetic nylon polymer may be more responsive to steam-vacuuming in returning to its original configuration. But, be sure that you understand the difference between roll crush in nylon or wool as opposed to olefin since olefin is far less resilient and therefore, less likely to respond to corrective measures.
Response: I am hesitant to continue since the manufacturer may be looking for a scape-goat. I have no desire to inherit their problem.
JB: Stand your ground, they don’t know anymore about it than you do.
Response: I realize that you are limited because of not being able to see the carpet.Thanks!
