Fastener Allowance for Expansion

All roofing and cladding are subject to expansion and contraction due to temperature extremes. This is particularly evident with darker colours and long spans where the expansion may be as much as 8 mm for a 10 m sheet. Screws fitted with profiled washers to allow for thermal expansion must be installed centrally through a 9 mm diameter pre-drilled hole in the roof sheeting.

Clause Number: 
Revision Category: 
1 - Minor Errata
Revision Detail: 

Fixed 8 mm for style consistency.