Most carpet installations require that two pieces of carpet align and attach to each other. The joint where the two pieces of carpet meet is called a seam. Seams are often glued together; however, the installer must bring the carpet pile together for the seam to show as little as possible. One of the tools used to bring the carpet pile together during the seaming process is called a seam roller.
How a Seam Roller Works
A seam roller is a hand tool that contains two small metal axles that have toothed metal wheels attached to them. Each axle is set on a pivot that allows the seam roller to put pressure on the carpet seam. When the installer aligns the center of the seam roller with the seam, the wheels push the carpet seam together and blend the pile from both carpet pieces together on the seam.
Why Use a Seam Roller
If the installer simply puts a carpet seam together by hand during a carpet installation, any imperfections in the seam become readily apparent. Likewise, the seam will likely be visible since the carpet pile was not blended together during the seaming process. The seam may also come loose; by contrast, a seam roller applies pressure to the seaming tape or seaming adhesive during the adhesive's curing or cool-down processes, securing the seam in place.
Padded Carpet Installation
Whether the installation is over tackless strip and padding or directly glued to the floor, an installer should use a seam roller every time he joins two pieces of carpet together to form one contiguous piece of carpet. For a padded installation, he should use a seam roller to apply pressure to a seam made using a seaming iron and hot-melt seaming tape. This allows the seam to lie flat and the carpet pile to come together once the seaming tape cools down completely.
While the installer attaches carpet pieces in a glue-down installation directly to the floor, it is still critical that he use a seam roller on any seams made on a glue-down installation. Like the padded carpet installation, the seam roller will apply pressure to the seam while bringing the carpet pile together. This has the net effect of presenting a flat seam that is difficult to see once the carpet glue cures completely.