Minimum Slope For Membrane Roof

Asphalt shingles minimum roof slope roof pitch r905 2 2.

Minimum slope for membrane roof.

The idea is to provide positive drainage toward roof drains so there is no ponding water 48 hours after a rain storm. The minimum slope for a flat roof is 1 4 per foot or 1 4 12 but some owners or insurance companies require a minimum slope of 1 2 per foot. To get the minimum pitch for a metal roof the vertical rise per foot is divided by the horizontal slope. For example the international building code 2018 edition ibc 2018 prescribes a 1 4 12 minimum roof slope for asphalt built up polymer modified bitumen thermoset and thermoplastic single ply and liquid applied membranes in new construction.

And if the performance of single ply epdm roofing on commercial installations is any measure weatherbond 110 can certainly last much longer than 12 years if it s properly installed. All nails must be covered with a membrane. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.

The minimum roof slope for metal roofs is dependent upon the roof profile. Minimum pitch for metal roof. The 12 year weatherbond warranty is to date the best i ve found in the category of residential low slope roofing products. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.

With regards to metal roofing the profile refers to the shape adopted by the metal sheets when they are bent to form the panels. Unroll and position the roll. This means for every 12 horizontal units the roof must rise a minimum of 2 vertical units. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.

This 1 4 12 minimum roof slope requirement also applies to spray polyurethane foam spf roof. Asphalt shingles continue to be the most widely installed roof covering option in north america. When the slope is rather steep 3 12 25 and above it is best to mechanically fasten the membrane by adding roofing nails to the horizontal overlaps every 12 in 30 cm before covering them with the next membrane strip note. Many building codes have a slope requirement for membrane roof systems.

The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. International building code 2012 edition ibc 2012 section 1507 require ments for roof coverings states all membrane roof covering systems except coal tar built up roofs have a design slope minimum of one fourth unit vertical.