Minimum Pitch For Flat Metal Roof

Even though manufacturers say 1 4 12 is acceptable.

Minimum pitch for flat metal roof.

However you can only use this pitch with built up roofing or specialized synthetic roofing. Roofing material or system. In 12 0 25 in 12 1 19 built up roof coal tar pitch. Low slope roofs are not totally flat their roof slope generally ranges from 1 4 12 to 3 12.

Most metal roofs will have minimum pitches of three in twelve but this might sometimes go down depending on whether there are special installation procedures issued by the manufacturer regarding that particular roofing material. The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run. To get the minimum pitch for a metal roof the vertical rise per foot is divided by the horizontal slope. Low slope metal roofs have simple geometries and are easier and less expensive to install that medium to steep slope roofs.

Low slope metal roofs require less material which reduces the overall load on the building s structure. 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. The minimum slope for lapped non soldered seam metal roofs without applied lap sealant shall be three units vertical in 12 units horizontal 25 percent slope. That is a 14 degree angle.

9 46 built up roof asphalt. Minimum metal roof slope depends on the roof profile building design climate and site location. That means there is at least 3 of vertical rise to the roof slope for every 12 it goes back horizontally. In retrofit projects a sub framing system is attached to the existing flat roof surface to provide a minimum 12 roof pitch.

Moreover low slope metal roofs are not prone to the degradation experienced by organic materials enabling these roofs to better resist the elements. Minimum required slope x in 12 minimum required slope degrees asphalt shingles. 18 43 asphalt shingles with special underlayment requirements 2 in 12. Corrugated metal roofing has the same minimum pitch.

That said if you want to have a metal roof that is worth its weight in value that doesn t come with a ton of problems the minimum pitch for metal roof applications should be kept at around at least a 3 1 2 12 three and a half on 12 or above.