Roof Pitch Requirements

Buildings with multiple roof.

Roof pitch requirements.

Anything above that will require you to put out higher cost because they are already considered as higher pitch. Whichever roof pitch you choose make sure that you select a roof covering that is designed. The minimum pitch is typically 3 12 meaning the roof should rise 3 inches for every 12 inches of horizontal foot. Your shed roof pitch may also be influenced by your project specific requirements to let light into the building through the roof or create storage space in the roof void.

The way pitch also known as roof slope is measured is rise over run. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. Minimum roof pitch for a covered porch minimum roof pitch. For every 12 horizontal feet the roof changes 8 feet in vertical height.

The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. 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. The covered porch roof pitch should match the existing house.

Let us recap on the minimum roof pitch required for each type of roofing material. Clay and concrete tile requires a minimum roof pitch of 2 1 2 12 or greater. 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. Metal roof shingles require a minimum roof pitch of 3 12 or greater.

The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code. Examples of extreme slopes range from 1 4 12 almost flat to 12 12 sloping down at a perfect 45 degree angle. Match pitch of existing roof. The standard of lower pitch actually ranges between 1 12 to 5 12.

Asphalt shingles require a minimum roof pitch of 2 12 or greater. For most home styles roof pitches fall in a range 4 12 a moderate slope up to 8 12 fairly steep. The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run. 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.

With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 200 for slate roofs.