Installer tips for pattern matching, seam sealing By Mark Aydin

Remember the first days working as a carpet installer when the assumption was once you knew how to seam, stretch and carpet stairs you could potentially go out on your own. Then you got a job that involved pattern matching and the seams didn’t look quite as they should. This was in part due to lack of experience and/or use of improper techniques, as well as not having the right tools or equipment.

Pattern matching carpet requires some prep work. To begin, gather as much information as possible about the product and the manufacturer’s tolerances. In general, be ready to make correction of one-inch in a 12-foot length for bow, 1.5 to 2 inches for skew, three-quarters of an inch to 1.25 inches for pattern elongation, and a half inch to 1.5 inches for edge deviation and/or trueness. These tolerances can vary depending on the manufacturer and carpet selection. Because of this, it is good practice to call the manufacturer’s toll-free helpline and speak with the technical department, regardless of whether confident you can deal with the tolerances. Next, take time to truly understand skew, bow and trueness of edge. Skew is a distortion in pattern squareness that is visible when the pattern on one side is slightly ahead of or behind the pattern on the other side.

Bow is the amount of deviation across the width, typically measured at the centre of the breadth. Bow occurs when seams or patterns are stretched out of alignment, curving away from and back toward a seam or centering point. A distortion visible as wavy or crooked pattern lines when viewed across carpet width is referred to as bow. Trueness of edge is one of the most underestimated elements that could ruin all your prep work. It describes S-shape edges that are nearly always present in some degree on all broadloom carpet and will need to be corrected by stretching the affected areas. Carpet may or may not have true edges, but all patterned carpet will have some bow and skew. Prior to installation, examine each carpet roll for pattern bow, skew and trueness of edge. Inspect the carpet across several breadths to determine where you will need to correct for bow and skew. The tolerances are based on how much a qualified installer can correct them by stretching the carpet. A power stretcher and matching seam/repair stretcher are necessary to correct for bow and skew. Always dry-fit the carpet before making any cuts, adjustments and bonding to the floor.

This will help you better understand problem areas and how best to address them. Once laid, it is time to seal the seams. This is one of the most crucial aspects of any carpet installation. When properly done, it prevents water from penetrating the flooring underneath and seam peaking, which is when the carpet tents up at the seam instead of lying stretched and flat on the f loor. To begin, apply a bead of seam adhesive to the cut edge of one side to seal both trimmed edges. Ensure the bead thickness is sufficient to cover the primary and secondary backing without contaminating face yarns. To bond together, join the seams while the adhesive is still transferable.

Mark Aydin is owner of Victorious Carpet and Flooring in Toronto. He is a certified residential carpet and resilient flooring installer, and a certified instructor for carpet and resilient flooring with the International Certified Flooring Installers Association in Canada. Mark is also a member of the Canadian Floor Cleaning and Restoration Association and previously sat on its board of directors.