I need to hang some hardibacker on a bathroom wall whose studs are a little over 3/4" back from a surface that the hardibacker needs to be flush with. I was going to rip wood strips a bit over 1/4" thick and attach those to the studs in order to bring the hardibacker flush with the existing wall. When I hang the hardibacker I want the screws to be firmly in the studs. The longest scews that are normally sold for CBU are 1 5/8" thick, which would mean that there would be less than an inch of the screws' threads in the wall studs. Which is less than I feel comfortable with. I have a box of 2" stainless steel decking screws that are long enough, but I'm concerned that the head on them is not wide enough. The head on CBU screws is about 3/8", the head on the stainless screws is 5/16". I have three questions.
Despite my doubts, would 1 5/8" CBU screws be long enough in this situation? Someone suggested that if I attach the 1/4" strips with construction adhesive that they would effectively become part of the existing studs.
If I use the stainless screws, will the smaller head be a possible problem?
Should I be taking an entirely different approach to this?
i think both solutions you have would work just fine.
if you use the shorter screws:
when you cut the 1/4" furring strips, make sure they are wide enough (say 6") so that when you attach it to the wall studs there is lots of surface area. also with the construction grade adhesive. then screw that into the studs and it will pull in tight so the glue will take hold. put the screws 1.5" from each end (top and bottom).
then when you attach the hardibacker try to get the screws to run down the center of your furring strip. so the 3 screws per stud are at least 1" away from each other (hence a 2nd reason why the wide furring strip).
do you need to insulate the walls and add vapour barrior with hardibacker? would be a good time to do it if required.
"if you can't be handsome, at least you can be handy" -Redgreen