1 12 Roof Slope

A 4 12 is a roof slope that rises by 4 inches for every 12 inches across.

1 12 roof slope.

This means for every 12 horizontal units the roof must rise a minimum of 1 vertical unit. Thatch is one of the oldest roofing materials and needs a steep pitch to drain properly some types of stone roofs have a very restrictive roof pitch. Mineral surfaced roll roofing can only be installed on roof slopes of 1 12 or greater 8 slope. Then you ll be able to measure slope from an unfinished attic space under the roof.

Slope ratio a roof that rises 4 inches for every 1 foot or 12 inches of run is said to have a 4 in 12 slope. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. Using a tape measure make a pencil mark 12 inches from the end of a carpenter s level. High and low pitch examples two examples at each end of the spectrum.

If a roof rises 1 in a length of 12 this is 1 12 roof pitch. A pitch over 9 12 is considered a steep slope roof between 2 12 and 4 12 is considered a low slope roof and less than 2 12 is considered a flat roof. Display of roof pitches 1 12 through 18 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.

The table below shows common roof pitches and the equivalent grade degrees and radians for each. Most roof s have a pitch in the 4 12 to 9 12 range. A 4 12 slope is enough to accommodate water runoff but is not suitable for regions that are. Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter.

Examples of extreme slopes range from 1 4 12 almost flat to 12 12 sloping down at a perfect 45 degree angle. This forms an angle of 18 5 between the horizontal section and the roof and creates a gentle incline that is seen as a midpoint between a low pitch and medium pitch roof. 1 12 roof pitch angle 4 76 degrees. For most home styles roof pitches fall in a range 4 12 a moderate slope up to 8 12 fairly steep.

With insufficient pitch a roof can leak rain and with a pitch too great its stones will fall loose.