Profiled metal roofing tearing at fixing points

Cause

The use of rivets instead of screws does not allow thermal movement to occur

Repair

  • it is important to make repairs because metal tearing or other deformation at fixing points may result in leaks through the roof

  • replace rivets with roofing screws. (Nails are not recommended – they have a higher risk of coming out and a poorer seal under the head)

  • where profiled metal sheet is a dark colour or a long span, allow for thermal expansion. Pre-drill 9 mm holes in the sheet roofing and install roofing screws in the hole centres with profiled EPDM sealing washers (see drawing) to allow for expansion

  • screw fasteners should go through the crests (the high part of the profile) and at least 30 mm into timber purlins

  • always tell someone else when you plan to work on a roof and take the appropriate safety precautions. You can find details here

Cause

Fixing holes are too small to allow sufficient thermal movement

Repair

  • as above