36mm Galvanised Steel Tile Backerboard Washers For use with Thermopanel Tile Backer Boards with the appropriate screws, our slimline galvanised steel washers grip tightly into the surface as they become almost flush with the board. Dimensions (each washer): 36mm diameter ( 5mm diameter screw hole). Thermopanel Tile Backer Board Fixing Washers, tailored for Thermopanel, Marmox, and Wedi boards, offer a robust solution for securely attaching insulation boards to both floors and walls. With a unique countersunk design, these Tile Backer Board Fixing Washers ensure the screw head integrates seamlessly into the board. This design choice guarantees a consistently smooth board surface, primed for the addition of subsequent layers.