I am going to close off a window between two rooms with an MDF board of suitable size. The other side is already closed off and I'm a bit afraid that if I attach the board directly to the studs holding the old board and tighten it until the new board is exactly level with the wall, there is a risk that the studs may shift, causing the wallpaper on the other side to crack. I want a small spacer as a buffer, and I'm wondering if there is a good material that is somewhat resilient so that I can tighten the screw to compress it until the board is positioned just right. (Filing wooden spacers to the exact thickness seems a bit challenging, as it's only when you really tighten it that you know how it sets.)
