Roof Truss Minimum Pitch

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.

Roof truss minimum pitch.

The best outcome of the pitch depends on the covering of the roof. However roof pitch is technically measured and defined differently and will not be discussed here. Most metal roofs will have minimum pitches of three in twelve but this might sometimes go down depending on whether there are special installation procedures issued by the manufacturer regarding that particular roofing material. 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.

To get the minimum pitch for a metal roof the vertical rise per foot is divided by the horizontal slope. For example if you use a heavy load of asphalt shingles a minimum pitch of 2 12 is needed for proper drainage. Rafter length from rise. I e 4 inches of rise per 12 inches one foot of run.

Note that roof pitch is sometimes used in parallel with roof slope. Wilson roof truss ltd. If you can t get the heel height most residential trusses will have a 3 top cord. Calculate the height of a common truss using the building width and the slope of the roof.