Are 1-1/4" cement board screws enough to hold the cement board and the tiles if I shim the studs wit

[Mini Me]

Due to an offset between the plumbing and the shower drain I need to float the wall on the short side of the shower base with like 3/4-1/2" so I am using top to bottom shims I am not sure if the screws that I have (1-1/4" Durock screws https://www.homedepot.ca/product/cg...k-cement-board-1-1-4-in-200-screws/1001341803 ) fit the purpose.

Can I still use then ? (they will be 1/2" in cement board, 3/8" in the shim and 3/8" in the stud

Just to play safe I bought these screws that are from a different manufacturer

https://www.homedepot.ca/product/ba...ar-drive-cement-board-screw-140pcs/1001157616

not sure if I can still use them with USG Durock cement boards

It seems that for both it is essential to have a larger head, coarse thread, resistant to corrosion and sharp enough to penetrate the cement board which is stronger than the dry wall

 

[Jadnashua]

1-1/4" screw, through 1/2" board and 3/4" shims means it won't penetrate the stud at all! I'd want at least 3/4" INTO the stud. I would not rely on the shim to hold the board when screwed through it.

Some brands of cbu screws are better than others...since you want the head to end up flush and penetrate without being a problem and not screw-jacking the panel up off the studs, the shape of the point is important. On some, the bottom of the head has a rib on it that acts like a countersink so the head will be able to become flush.

 

[Sponsor]

 

[Jeff H Young]

too short. I'd go 2 inch

 

[Mini Me]

Since then I had to sister all the studs and give up on using shims because it was a disaster on one of the walls, the one I had to float like a little bit more than 1/4in
I used 1 1/4" screws since I alread had them