Maximum Spans and Permissible Unsupported Overhang
The permissible spans between purlins or rails and the maximum unsupported overhand at eaves are detailed in the table below.
|Profile||Max Centres||Clear Span||Max Centres||Clear Span||Max Sheet Overhang|
Ensure all purlins and rails are within the specified spacing for the profile and end lap to be used and are firmly fixed to the structure.
If possible please commence laying sheets at the gable end away from prevailing wind.
It is necessary to mitre opposing corners of two sheets where four sheets intersect (detailed in diagram).
Mitres should be clean cut as a straight diagonal.
Do not box mitre under any circumstances as the weathering effectiveness will be seriously reduced. Clearance of assembled mitre should be within 3 to 6mm to ensure adequate weather sealing.