Avoiding Metal Roofing Problems
Damage investigations from 2016 have revealed that some metal roofing systems have sufficient strength to resist extremely high winds, while other systems have blown off during winds that were well below design wind speeds. When metal roofing (or hip, ridge, or rake flashings) blow off during severe weather conditions, water may enter the building at displaced roofing; blow off roofing can damage buildings and injure people. This is because the wind uplift forces are greater than the weight of the roof and the “tie-down” fixings are, in some cases, not strong enough to resist the uplift effect.
A total of 123 building sites were inspected from January to October 2014 covering 26 Perth suburbs and WA’s South West coastal region
More than 50% of those metal roof inspections showed defects and were found not satisfactory. Mostly related due to missing tie down system of the roof structure. Many roof carpenters were not aware of the new requirements (AS 1684.2- 2010). and neither the building inspectors or compliance officers.
628 metal roofs showed some defects (mostly missing tie down straps) and only 308 of them were found satisfactory. Some other could not be evaluated due to lack of access to the roof void.
The current Standard for Pre-Purchase inspections states:
A pre-purchase inspection should not be construed to be any of the following:
- code compliance inspection. Commenting upon codes and standards is beyond the scope of a typical pre-purchase inspection
- The Report is not a certificate of compliance that the property complies with the requirements of any Act, regulation, ordinance, local law or by-law, or as a warranty or an insurance policy against problems developing with the building in the future.
That means that some building inspectors for your pre-purchase inspections won't and don't need to report on any missing tie down straps as a pre-purchase inspection it is not a compliance inspection!