Solve Synthetic Turf Seams Problems

Most synthetic turf problems are seam failures due to poor adhesive selection because both buyers and installers don't realize the importance of using a "high green strength" adhesive. However, most of the seam installation problems and durability problems later can often be solved by using a "high green strength" adhesive.

Q: Please explain the term "high green strength" adhesive, plus the difference between it and one with low green strength.

A: High green strength adhesives have inherently high tack/grab/gripping properties during installation, as opposed to most adhesives that are low green strength (oily/slippery liquids) after application and during cure.

High green strength adhesives overcome the troublesome forces of turf movement that plague turf during installation, particularly outdoors, such as "wind lift"; edge curl; creep; wrinkling; buoyancy from unexpected rain; expansion and/or contraction due to surface temperature changes from desert heat; freezing; sunlight; shadows; passing clouds; etc. Conversely, low green strength adhesives are the opposite (slippery, no grip) also causing "squeeze-out," "oozing" and "foaming" through seams.

Q: Now that we know the differences, can you give us some generic examples of good high green strength adhesives that overcome installation problems and oppositely, those that do not have high green strength?

A: One-part liquid urethanes that are solvent-free do not have green strength. Additionally, their high isocyanate (NCO) contents above 8 percent cause nightmares and a host of installation problems ranging from crystallizing (turning solid) at about 50° F and not re-liquefying when warmed, to foaming under the turf and through seams in high humidity, to slow cure in low humidity, to negligible tack and "grab," which allows unwanted turf movement during installation.

Oppositely, many solvent-based one-part urethanes with low NCO from 3 to 6 percent have high green strength, which enables turf installations ranging from sub-freezing to hot desert temperatures. Also, they do not crystallize on cold days, do not foam on humid days, and do not stop curing in dry desert-like conditions. Unexpected rain immediately after application doesn't hurt them. Hence, installers don't have to "babysit" them during installations or immediately after.