Screws and fixings for installation
How to choose the right fixing
Trade tip: For external window fixings, always specify A2 or A4 stainless steel over BZP zinc-plated. BZP screws corrode behind UPVC profiles over time, causing staining and seal failure that is expensive to fix and voids most manufacturer warranties.
Frequently Asked Questions
What screws do I need for uPVC windows?
Self-tapping window screws (3.9 x 13mm) for beads, handles and hardware. They tap their own thread without pilot holes or splitting the plastic. For frame-to-subframe fixing, use longer frame fixings (70mm+).
Can timber-to-steel screws go through steel without pilot holes?
Yes — TechFast timber-to-steel screws have a No.3 drill tip that self-drills through steel up to 5mm thick. No pre-drilling required.
What is a waferhead screw?
A screw with a large, flat, low-profile head that sits almost flush. Used for frame-to-frame connections where a protruding head would interfere with glazing beads or sealed units.