Minimum Slope Of Pitched Roof

The minimum roof slope for metal roofs is dependent upon the roof profile.

Minimum slope of pitched roof.

The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code. It is uncommon to find a roof below 15 but for those very low pitch applications there are interlocking clay pantiles available suitable for use down to 12 5. A ratio is the most common way of expressing roof pitch or roof slope but degrees are also possible. With regards to metal roofing the profile refers to the shape adopted by the metal sheets when they are bent to form the panels.

If a roof slope rises say 4 inches when measured 12 inches along the bottom of a horizontal roof truss the roof slope is said to be 4 12. Roof pitch is the measurement of roof steepness. Asphalt shingles can only be installed on roof slopes of 2 12 or greater. To get the minimum pitch for a metal roof the vertical rise per foot is divided by the horizontal slope.

The minimum roof pitch for shedding snow is around 30 or a 6 12 or 7 12 slope although this is not a definite as the material of your roof the direction of the snow and wind are some factors that can affect whether or not snow will slide as roofs of as little as 10 have been reported to shed snow. The metal roof minimum slope doesn t stray far from other building with different material. The standard of lower pitch actually ranges between 1 12 to 5 12. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.

The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run. Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio. The minimum pitch is typically 3 12 meaning the roof should rise 3 inches for every 12 inches of horizontal foot. However you can only use this pitch with built up roofing or specialized synthetic roofing.

So if your roof rises 4 inches for every 12 inches of horizontal length then the pitch of your roof is expressed as 4 12. Minimum pitch for metal roof. The way pitch also known as roof slope is measured is rise over run. This means for every 12 horizontal units the roof must rise a minimum of 2 vertical units.

Note that roof pitch is sometimes used in parallel with roof slope. Traditionally a minimum roof pitch of 20 was recommended in bs 5534 but modern tiles and slates have now been designed for applications as low as 15. However roof pitch is technically measured and defined differently.