Rant: People keep using gripper strips that are way too thick for standard underlay

Caught a job last month where the previous guy used 10mm grippers with 8mm foam, and the carpet was buckling at every doorway - has anyone else had to rip out bad strips because someone ignored the height specs?

3 comments

3 Comments

skyler_kim1mo agoMost Upvoted

Last year I measured a job where the builder swore 10mm strips with 6mm underlay was fine, but the nap height on the carpet itself pushed everything over the limit. Nobody ever talks about how the carpet pile compresses under door thresholds and makes that height difference even worse. Maybe we need to start factoring in the carpet's actual thickness, not just the foam, when picking strip size.

margaret_singh11mo ago

Yeah @skyler_kim, learned that one the hard way on a job last spring-pile height always screws the measurements.

simonmoore23d ago

Read an article just last month from some flooring trade journal that did a deep dive on this exact problem. They tested like 15 different carpet types with different underlay and strip combos. Turns out the actual compressed pile height under a door threshold can be a full 3mm more than what you'd measure with a gauge on open floor. So you're not just dealing with the underlay thickness, you're dealing with the carpet's whole profile mashing down under the door. Thats why I always add 4mm to whatever the underlay and strip spec says on paper. Better to have a tiny gap than to be shaving door bottoms on every room. That article really hammered home that nobody talks about the dynamic compression factor.