Minimum Slope For Membrane Roof

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Minimum slope for membrane roof.

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. 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. 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. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.

Asphalt shingles continue to be the most widely installed roof covering option in north america. 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. With regards to metal roofing the profile refers to the shape adopted by the metal sheets when they are bent to form the panels. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.

This means for every 12 horizontal units the roof must rise a minimum of 2 vertical units. Asphalt shingles minimum roof slope roof pitch r905 2 2. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.

The 12 year weatherbond warranty is to date the best i ve found in the category of residential low slope roofing products. The minimum roof slope for metal roofs is dependent upon the roof profile. Many building codes have a slope requirement for membrane roof systems. Asphalt shingles can only be installed on roof slopes of 2 12 or greater.

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. 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. The idea is to provide positive drainage toward roof drains so there is no ponding water 48 hours after a rain storm. To get the minimum pitch for a metal roof the vertical rise per foot is divided by the horizontal slope.

This 1 4 12 minimum roof slope requirement also applies to spray polyurethane foam spf roof. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.