A carpet inspector posed a question today about how long you should keep traffic off newly installed carpet when it’s directly glued down to the substrate. The reason for the question was indentations in the carpet surface that, they say, would not come out from furniture having been placed on it. The carpet was glued down in office areas and the furniture was moved from one side of the room to the other to accommodate the installation. Immediately after an area was carpeted the furniture was moved back onto the newly installed sections. The furnishings included heavy filing cabinets, desks and divider panels. This furniture was not set up on the newly installed carpet but it was stored and stacked because they had to wait for the opposite areas to be carpeted before they could arrange things the way they wanted them. The complaint is there are indentations in the level loop nylon carpet from the furniture being placed on it immediately after installation while the adhesive was still wet.
I can appreciate the logistics behind an installation procedure like this. Instead of having to remove all the furniture so all the carpet could be installed at one time, it makes perfect sense to move the furniture from one side of the area to the other side. The problem arises when and how you do this.
Placing heavy objects on newly installed, glued down carpet with a woven synthetic backing, when the appropriate amount of adhesive is applied, could cause permanent indentations. This can happen because the appropriate amount of adhesive would be an amount applied with a 1/8 x 1/8 “U” notched trowel and a spread rate of 5 to 8 yards per gallon. This is a thick application of adhesive. The carpet should be rolled after installation to push it into the adhesive and insure there is proper transfer and adhesion. Placing heavy furniture with a small “foot print” on carpet that is low profile with a thick layer of adhesive under it can cause the adhesive to ooze far up into the backing and even penetrate the base of the carpet yarns depending on the construction of the carpet. If the material is porous or if the backing has ribs in it with a woven synthetic secondary backing it is possible the adhesive will penetrate far up into the carpet. It could certainly penetrate far enough into the carpet to permanently hold down more of it than you would normally expect. If this happened there could be permanent indentations in the carpet.
Normally, indentations in level loop nylon carpet will relax out by themselves under normal ambient conditions. If they don’t come out on their own they can be steamed out using a Jiffy Steamer or similar steaming unit to force them out. You have to be careful using live steam on a carpet glued directly to the substrate though because you could break the bond of adhesion or weaken it.
When the adhesive is wet however, and heavy weight is placed on it and allowed to sit, the indentations could be permanent. As, explained, the weight of the furniture could push the carpet far down into the adhesive, the adhesive far up into the carpet and when it dries it can hold the carpet in that shape. If this should happen the indentations may never completely come out. This would be like glueing a piece of paper in place with an adhesive and then pressing your finger tip into the paper creating a permanent indentation.
So, what should you do if you have to install carpet under these conditions? The furniture should be moved on flat sliders across the carpet and plywood or masonite should be put down where you slide, walk, carry and place the furniture. This way the pressure from all this activity will be dissipated over a wider area and the plywood or masonite will prevent indentations in the carpet and adhesive squeezing up into the carpet backing.
Actually, traffic should be kept off the carpet for at least 24 hours before any traffic is placed on it so the adhesive can set up and not be disturbed. If you’re installing a carpet with the double stick method, that is, glueing the pad to the floor and the carpet to the pad there should be absolutely no traffic on the carpet for at least 24 hours.
It may be rare that you experience this type of a problem but it can occur. I’d be willing to bet that installation failures that occur within a relatively short period of time in traffic areas of direct glued down installations could fail, in part, due to too much traffic on the carpet too soon after it’s installed. There is no industry standard for this and there is no published guideline for it either but common sense, which is at times a rare commodity, should tell you this is not a wise thing to do. This is a problem caused by whoever said to move the furniture onto the newly installed carpet. The dealer should protest this action and insist on no traffic on the carpet or at least insist plywood or masonite be put down. This is not an installation problem, nor can the manufacturer be blamed. It’s the fault of whoever said it was ok to put heavy furniture on newly installed carpet.