Why do some Torchon membranes wrinkle at the line of the plywood joints?
A. This is more likely to occur to fully bonded membranes with APP modification. SBS membranes, which have a high degree of memory, are less likely to show this wrinkling or ridging even if fully bonded. Spot bonding or using an un-bonded but mechanically fixed underlay or first layer eliminates this problem.
