Carpet seam visibility is one of the most common problems cited by consumers, according to flooring specialist Tim Clavey's site. The industry standard requires only that seams be tightly abutted, have no frayed edges and continue the pattern match where applicable. These guidelines leave significant room for problems to develop when installation does not take into account other factors such as carpet material, traffic patterns and usage. Locating seams under strong lighting will help to hide them, as well as putting them under furniture.
Seam separation can occur when the primary and secondary backing on the carpet separates, a process called "delamination." This process causes pulling at the sewn seams and rippling of the carpet surface. Seam separation, where the carpet is the weakest, often occurs in high traffic areas. A professional installer will know not to place the seams in these areas, but it's a smart idea to mention where the high traffic areas are located to any installer who works in your home.
Seam fraying often occurs in doorways where carpeting meets other types of floor surfaces like wood, tile or vinyl flooring. The fraying may even show part of the carpet backing. Professional installers generally put a bead of seam adhesive on the carpet edge to prevent this problem, but some skip this important step. Ordinary wear and tear on carpeting at these high-traffic points can cause the edges to fray.
To repair separations in carpet seams, remove any old glue at the separation site, cut down frayed ends and carefully match the seam into its correct position. Lift the carpet edge and apply adhesive, then melt the adhesive with an iron. To repair fraying problems, add a carpet bar at transitions to other types of flooring. You may need to stretch the carpet to remove ripples to make it fit snugly under the bar, which is then nailed down to the subfloor. You may need to cut away a large area of the fray and re-stretch the carpet to fit under the bar. For serious seam separation or constant fraying problems, consult with a carpet professional to do the repairs properly.