Usual Roof Pitch

Roof pitch varies depending on culture climate style and available materials.

Usual roof pitch.

Greek says one must keep rafter length in range of 1 9 to 1 7 th of span but as per roman style the standard dimensions are kept about 1 3 to 2 9 th of span with an angle of 23 to 24 degree. Pitches lower than 4 12 have a slight angle and they are defined as low slope roofs. Usually average roof pitch is determined using the same roof length method. In the usa the range of standard pitches is anywhere between 4 12 and 9 12.

Express roof pitch as the ratio of the amount of the vertical rise of a roof or rise over the corresponding horizontal distance or run you write the pitch assuming a run of 12 inches thus the ratio would describe how much a roof rises for each foot of the run. There are some standing seam metal roofing options available from atas and other manufacturers that can be installed on a roof with pitch of 1 12. 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. You could also opt for a pvc flat roofing membrane.

Pitches of less than 2 12 are considered flat roofs even though they may be very slightly angled. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. In the uk the typical house has a pitch between 40 50 although 45 should be avoided. Commonly it is 3 4 th of span as per gothic rafter must be equal to span.

There is no standard universal roof pitch. Pitches above 9 12 are very highly angled and are designated steep slope roofs.