Our Tile backer board fixing washers have been specially designed to provide an easy secure way to fix Thermopanel, marmox and wedi type insulation boards to floors and walls. We hold large stocks of Washers and Tile Backer Boards, so please check out the other items in our shop. If you are unsure of what you require please do not hesitate to contact our help team. Our advice is free and we are here to help. The washers are easy to fix and have been specially designed for use with Tile Backer Boards in three specific ways: 1: The washers are countersunk to allow the screw head to pull into the board but the outer rim of the disc to remain flush with the board surface. This is to maintain the flat board surface ready for easy unhindered application of the subsequent layers.