If asphalt shingles are to be installed on a low slope roof special steps are required to avoid short roof life and roof leaks.
Roof slope multiplier table.
Typically the steeper the roof is the higher the price will be.
Understanding the roof pitch chart process.
If the home measures 20 x 40 and has a 7 12 roof then to calculate the slope of the roof follow these steps.
800 multiplied by 1 16.
Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio.
Take the area of the roof s footprint say it s 5 000 square feet and multiply 5 000 by 1 118.
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.
And for a roof with a slope of 6 12 that number 1 118 is your roof slope multiplier.
For example if you measure 4 inches the pitch of your roof is 4 12.
Divide the rise by the run the run is 12.
Low slope roofs are from 0 to 3 12 in pitch.
Step 1 multiply 20 and 40 which equals 800.
Also see our page quick reference.
Some sources consider low slope to include 3 12 pitch roofs.
Step 2 find the value of 7 12 from the roof slope multiplier table which is 1 16.
Simply multiply this number by the area covered by a sloped roof to obtain the total surface area of the roof itself.
Find the square root of the result.
See below after the table for directions on how to convert any roof slope from one form to another even roof slopes not shown in the table.
The hip and valley factor varies according to the slope of the roof as shown in the table below.
For any roof slope expressed as x in 12 rise in run the hip and valley factor is determined by finding the square root of rise run 2.
Notes to the table above.
A roof pitch multiplier also called a roof pitch factor is a number that is multiplied by the area covered by a sloped roof to produce the area of the actual surface of the roof.
The first thing that you need to understand before picking any selections from a roof pitch multiplier chart is to ensure that it s affordable.
That gives you 5 590 square feet which is the actual area of the surface of the roof.
This will give you the rise over run or pitch.
Degrees to roof pitch rise in run to see a table.
It s just a little math.
Step 3 multiply step 1 and step 2 i e.
Although there s isn t any standard pitch of a roof used on all kinds of sloped roofs you can determine the range of pitches by using a roof angle calculator and by considering factors like the local climate and roofing materials.
The roof pitch multiplier is a number that allows you to find the total surface area of your roof.
The following table shows how the same common roof slopes can be expressed using rise in run ratios degrees and percentages.
