I have radiant heating tubes running under my subfloor. When installing the backer board it is painful, impossible in some situations, to try and hit joists for every seam. We are using thinset to set the backer board in. I have used 1-1/4" screws on every joist, but there are a few locations where a shorter screw would be nice. Say 3/4" - 1". Any chance I can find a shorter screw that will work in this situation?
You are not supposed to hit the joists when installing the backer, it's fastened into the subfloor. 1 1/4" wouldn't penetrate the joists much anyway. You can use roofing nails instead of the screws. But 3/4" fastener is too short. I'd stay with 1 1/4". Your tubes aren't that close to the subfloor is it?
TILE GUY - retired- TROY, MI - Method & Product suitability consulting.