Purlins must be at the correct centres and not less than 25mm square, supported by rafters. A useful tip is to use a timber spacer to keep purlins square to eaves.
If cutting is necessary, use a fine toothed hand saw or circular power saw, lubricating the cut with general purpose lubricating oil to prevent binding.
3. Laying the sheets
Commence fixing sheets at the opposite end of the roof to prevailing winds. Stagger the sheets using half a sheet to start the second course.
Nail through sheet crown into purlins or decking. Nail every corrugation at sheet overlaps and at the top and bottom of the slope. Nail centres may be reduced to alternate corrugations at intermediate purlins.
5. Fixing ridges
Commence fixing ridges at the opposite end of the roof to prevailing winds. Overlaps should be 125mm. Additional purlins should be fitted to suit.
Verges should be formed by either nailing the final corrugation over a raised barge board or using a ridge piece to lay over the verge
7. Fixing Gutters
Do not overhang fascia by more than 70mm. Draughts may be reduced by using Coroline Polyethylene fillers at eaves..