How do you calculate the slope factor of a roof?

The roof slope factor is written as “x/12,” where “x” is the vertical distance you measured from roof to level. For instance, if the measurement was 3, your roof slope factor would be 3/12, and you would have a roof with a low slope.

What is a 25% roof slope?

Example: For a slope of 25%, 25 divided by 100 = 0.25. 0.25 x 12 = 3. giving you a slope of 3-in-12.

What is the code minimum for roof slope?

The minimum roof slope allowed by code for any type of roof is ⅛-in-12 (0.60 degrees), applicable only to coal tar pitch roof systems. All other flat roof materials require a minimum slope of ¼-in-12, which is why flat roofs are properly known as “low-slope” roofs.

What is hip and valley factor?

What is a Hip and Valley Factor? The hip and valley factor is a number that is multiplied by the run, or horizontal distance covered, of a common rafter to determine the length of a hip or valley rafter. Repeat, the horizontal distance covered, not the length, of a common rafter.

How do you calculate the rise and run of a roof?

Calculate the roof rise using the figures for unit rise and total run. Multiply your figure for unit rise by your figure for total run to get the total rise. Using the example, it would be six inches times 13 feet. The total roof rise in the example equals 78 inches.

What pitch is too steep to walk?

Most roofers consider a roof a “ Walk “ until it is 8/12 or more. So a common roof pitch of 4/12 or 6/12 would be OK to walk on . An 8/12 roof or steeper usually requires roof jacks or scaffolding .

What kind of roof do I need for a 1/12 pitch?

Mineral-Surfaced Roll Roofing can only be installed on roof slopes of 1:12 or greater (8% Slope). This means for every 12 horizontal units, the roof must rise a minimum of 1 vertical unit.

Does a roof have to be a certain pitch?

A: Roof pitches traditionally range from 12.5° (anything less is considered a flat roof) up to 75°. The key is ensuring the correct roofing products that are suitable for the roof pitch.

Is a valley rafter the same as a hip rafter?

A hip rafter is called for only when framing a hip roof, but a valley rafter is needed on both hip and gable roofs whenever roof planes intersect.

What is roof Valley?

A roof valley is formed where two roof slopes meet. Water collects in a valley to flow off the roof. Your choice of valley installation method is critical because, when improperly installed, valleys are risks for serious leaks. Essentially, there are three main ways to shingle a roof valley: woven, closed-cut and open.