Knauf Cement Board Screws — Alkali-resistant

Special screws with an alkali-resistant coating for fixing AQUAPANEL cement boards and GUARDEX exterior panels. Designed to withstand the alkaline environment of cement — where a standard screw would corrode.

Cement boards and exterior glass-mat boards create an alkaline environment with a high pH. Standard phosphated screws corrode, leaving rust and losing strength. These screws feature an anti-alkali coating and a special head/thread (maxi) that ‘grips’ the hard cement board, for secure, permanent fastening indoors and outdoors.

Which screw should I choose:

Always use an alkali-resistant screw for cement board/external glass-mat board — never a standard plasterboard screw.

SN / NP (sharp) → thin metal studs.

SB / DP (self-tapping) → heavier studs, no pre-drilling required.

AQUAPANEL → maxi screw SN/SB & pointed/drill-pointed cement board screws.

GUARDEX (facades) → AQUAPANEL Screw Exterior GMR (NP pointed / DP drill-pointed).