Field guide
Installing corrugated sheet safely
The right order of operations for laying corrugated zinc-aluminium sheet on a timber-framed roof — and how to keep it watertight.
01Tie off first
Set your anchor at the ridge and clip in before you carry a single sheet up. Never work a sloped roof without fall protection.
02Lay to the prevailing wind
Start at the end away from the prevailing wind so each new sheet laps over the last on the weather side. Snap a chalk line at the eave to keep the run straight.
03Fix at the crown
Drive self-drilling screws through the top of the corrugation, not the valley, so water runs past the fixing. One screw every second crown at each purlin.
04Lap correctly
Overlap side laps by one and a half corrugations and end laps by 150mm. Seal end laps with butyl tape in high-rainfall areas.
05Cap the ridge
Finish with the pre-bent ridge cap lapped over the top course, screwed through the crown and taped underneath to lock out driven rain.