Will be putting up some of this stuff as a tile backer around a tub. Any tips on: 1) cutting it 2) screwing it or otherwise attaching to wall- do I use regular black wallboard screws or go with galvanized deck screws? 3) will the little wallboard thing you can put at the end of a drill to properly set screws work with cementboard?
I just did a shower surround with CBU, and was my first time installing it - onto metal studs, but a couple things I learned:
- Cutting: my circular saw did well with a special carbide blade attached... DONT try to use a regular blade, will spark and probably ruin your saw. BUT, it creates a massive amount of dust, so do well away from the house outside with a mask and goggles. Also, I found that a utility knife w/ carbide blade worked better, just a little slower. I bought a carbide tipped 1 1/4" circle hole cutter bit for my 12 volt cordless drill, and that worked real well for getting the shower head and handle fixture holes cut.
- Mounting on the wall: like Ron said, they sell special screws for Hardibacker/Durock. In my mind, worth the extra couple bucks because I was worried about water/rust. Be sure to spread a separate coat of thinset over them.
- Mounting: I'm curious if the pros will agree, but I found that pre-drilling with a carbide tipped bit through the CBU and into the metal stud, then going back in with the Hardi screws on my screw gun made it much easier. I arrived at this method because some of the initial screws I just went in on the end of the CBU on the stud came real close to the edge of the CBU piece and caused it to crumble on the edges.