Low Slope Roof Section

The usual slope for asphalt shingles is a 4 or greater rise for every horizontal foot of run.

Low slope roof section.

The membrane will outlast the shingles and seal around all nail penetrations. Low slope structural roofing generally used on roof pitches ranging from 12 to 3 12 consists of interlocking panels commonly called standing seam roofing that run vertically along the roof surface. A 3 per foot slope is considered low but may be acceptable if a double layer of felt is used. These panels generally come with a painted mill finish or a clear acrylic finish.

For anything less than that you should use a roofing material specifically made for low slope roofs. That includes soldered metal roofing or synthetic membranes. Vertical end laps should be at least 3 inches and horizontal laps 6 inches. Some building codes allow as low as a 2 slope with asphalt shingles if additional steps are taken.

Significant insight may be found in asce 7 section 8 4 as referenced in ibc section 1611 2. Then apply standard asphalt shingles over the membrane. Iko roof fast low slope roofing components are engineered and manufactured to meet those particular challenges. The only function the three tab shingles perform at that low a slope is decorative that s a legitimate use of shingles when you wish to preserve a consistent appearance but they do not function as a weather barrier in such installations that function is being performed it s being performed at all by the underlayment and or flashing below the shingles which in this case must be a material with self sealing properties to prevent water intrusion at the shingle s fasteners.

Low slope roofs present special challenges in terms of preventing unique types of damage. 1 cover the entire surface with a self adhesive flashing membrane such as grace ice water shield there are many equivalent products. Roof fast 95 base iko roof fast 95 base is a self adhesive product that can easily be cold applied on low slope roofs. The reason water ponds on a low slope roof is a possible misinterpretation of the 1 4 in 12 minimum slope by the building code.

For a low slope residential roof there are two main options. Regular asphalt shingles and standard skylights will work at pitches of 4 12 or greater but at lower pitches you have to use different materials. Roof coverings installed on low slope roofs roof slope 2 12 in accordance with section 1507 shall resist impact damage based on the results of tests conducted in accordance with astm d3746 astm d4272 cgsb 37 gp 52m or the resistance to foot traffic test in section 5 5 of fm 4470. For buildings with low slope roofs less than 2 12 slope the wind speed at eave height is used.