Minimum Pitch For Corrugated Plastic Roof

The pitch is measured in inches of vertical rise per foot of horizontal run and the 5v crimp profile shown above requires a minimum slope of three in twelve or 3 12 3 inches vertically per 12 inches horizontally.

Minimum pitch for corrugated plastic roof.

3 pre notch rafters to compensate for allow a 1 minimum pitch per foot for adequate drainage. The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run. Corrugated roofing is a great material on traditional pitched roofs but it has severe limitations when the pitch gets below 5 degrees. The standard of lower pitch actually ranges between 1 12 to 5 12.

That is why all roofing manufacturers recommend the 5 degree pitch as the minimum slope and they will not provide any guarantees if it is installed flatter than this. In most occasions a pitch of three in twelve is preferred but this should also take into consideration the manufacturer s recommendations as well the unique condition of the corrugated metal roof. For a secure and attractive finish you should use molding strips on top of the rafters. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.

If your roof has a shallower pitch you may need to use additional weatherproofing measures. Just like other metal roofs the minimum pitch for a corrugated metal roof largely depends on the profile of the roof. The cladding should be supported at maximum centres as specified by the manufacturer and fixings should be a minimum of 50mm from sheet ends. Allow 7 4 from floor to bottom of front header for best ventilation.

Corrugated metal roofing has the same minimum pitch. However you can only use this pitch with built up roofing or specialized synthetic roofing. Anything above that will require you to put out higher cost because they are already considered as higher pitch.