The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
Min roof slope salt box house.
You can also divide the rise over run multiply by 100 and get a percentage.
Because of the asymmetrical design of the saltbox roof it is a great option for people living in the northern climates where rain and snow are plentiful.
The unique design allows for the back roof to suffer most of the winter snow while the steep slope allowed for snow to slide off of the roof limiting snow buildup and the potential of the roof failing due to heavy snow loads.
Building a building with a saltbox roof is a little more complicated than your traditional truss roof.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
You could also opt for a pvc flat roofing membrane.
You must make sure that the pitch of the roof coincides with the walls that are used to frame the rear of the building.
A saltbox roof is similar to a gable roof but has different slopes and or spans for the front and rear sides of the roof.
Great for northern climates.
Builders decided that the saltbox house was one of the most practical choices for the region.
So you would need to pick the right option as most regular standing seam metal roofs will require a roof pitch of 2 12 or even 3 12 at a minimum.
To calculate a saltbox roof select saltbox from the roof type dropdown list or select the corresponding button on the toolbar.
A 4 12 pitch is around 18 5 degrees but not exactly.
Thus a 4 12 pitch would be a 33 slope.
The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run.
However rise over run is more efficient and easier to understand for the average diyer.
This will result in one wall being higher than the other.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
As exemplified by the ephraim hawley house a famous connecticut saltbox built in the 1680s and.
Sturdy and understated they are.
The resulting shape also known as a catslide was almost triangular with one long roof slope plunging two and a half stories from the ridge almost to ground level and a short steep slope nearly parallel with the wall on the other side.