Fireplaces, Heating Stoves, Flues and Chimneys - wonderboard behind woodstove

I'm planning on using wonderboard mounted on ceramic risers behind a woodstove. My problem is this. I'm using half inch board attached to wall studs every sixteen inches or so. Even with this many the board still has movement when pushed. It bows under pressure. I plan on putting ceramic tiles over the wonderboard but am concerned that the flex in the board will screw things up.

I'm pretty sure that this is fairly standard stuff for behind a stove but I can't figure out how the smart guys install it to make it rigid.

Thanks

Derek Roberts

Hello Derek
add a stud and make it 8" o.c. or a fire block top and bottom and in the middle this will make it stiffer should be all you need to do use thins set to install the tile......Good Luck