Minimum Angle For Pitched Roof

Normal roof slope for typical installation.

Minimum angle for pitched roof.

To convert between american roofing ratios and pitch degrees follow these steps. Divide the first part of the ratio by 12 to work out the pitch. The loft space would be much larger with a roof pitch of 45 degrees. The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.

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. For that reason flat roofs are limited to these types of covering materials. 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. Find the inverse tangent of the pitch to find the angle in degrees.

The roof pitch calculator is a convenient online tool you can use to quickly assess the pitch of your roof to determine the length of rafters you need. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. If 4 12 and above is normal and 2 12 is minimum what about properties with roofs in between the two such as a 3 12 pitched roof. The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7.

Pitched roofs can also be used to incorporate roof lights angled in a specific direction or dormer windows artists commonly use north facing roof lights to allow cool light into their studios. But since there is still a wide variety of slate roofing systems there are occasions when the minimum pitch can go down to as low as 15 0 depending on the uniqueness of the roof. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 200 for slate roofs.

Minimum roof pitch for shingles. A 12 12 pitch roof has a pitch angle of 45. However you can only use this pitch with built up roofing or specialized synthetic roofing. Normal shingle installation is allowed for all roofs with a pitch of 4 12 and above.

Asphalt shingles continue to be the most widely installed roof covering option in north america.