Polyester Seam Fabric for Joint Reinforcement GoBoard® Seam Fabric is a lightweight, point-bonded polyester fabric designed to reinforce GoBoard panel joints and changes of plane. It strengthens the completed joint when used with GoBoard Pro Sealant but does not replace the sealant or provide waterproofing by itself. Stronger GoBoard Joints and Thinset Bonding The alkali-resistant fabric increases joint strength by more than 50% and improves shear bond strength by more than 30%. It also creates a bondable intermediary surface between GoBoard Pro Sealant and thinset mortar for a stronger tile backing assembly. Faster Preparation for Tile Installation Thinset mortar can be applied after the fabric is embedded into wet GoBoard Pro Sealant without waiting for the sealant to skin over. The 3" × 300' roll can be cut to the required length for reinforcing GoBoard joints and transitions in applicable wall and floor installations.