Roof Pitch Multiplication Factor

You need to first figure out the dimensions of the roof by multiplying the length with width to calculate the square footage.

Roof pitch multiplication factor.

Multiply the result by the factor and this is the length of the roof from base to ridge. For example suppose you have a 4 12 pitch roof and the width of the house is 28 feet. For roof slopes expressed as x in 12 rise in run the roof pitch multiplier is determined by finding the square root of rise run 1. On blue prints architects engineers usually display the pitch of a roof in the format shown on the image where number 4 represents a rise and number 12 represents a length.

Looking at the chart the factor is 1 0541. Dividing the house width by two equals 14 feet. Roof pitch factor calculator. Pitched roof provide you protection again heavy rains.

If the home measures 20 x 40 and has a 7 12 roof then to calculate the slope of the roof follow these steps. 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. Two most common methods 4 12 or 4 12 are used for marking the pitch of a roof. The roof pitch factor will help in figuring out the exact roof estimate.

Step 3 multiply step 1 and step 2 i e. To obtain an accurate roof pitch measurement properly measure the rise and run. In order to calculate roof pitch find every inch the roof will rise for every 12 it runs or spans. From the roof pitch factor table note down the roof pitch conversion factor corresponding to the roof pitch calculated.

To find the roof pitch you need to place a level across the top ridge with a 12 mark that rests directly above the center top of the ridge. 800 multiplied by 1 16. Using a tape measure make a pencil mark 12 inches from the end of a carpenter s level. The combination of two numbers are used to display or show the roof pitch.

Then you ll be able to measure slope from an unfinished attic space under the roof. If you have already decided that you are going to have pitched roof on your house then you have made a nice decision. In our example the roof pitch was calculated as 9 12 which has a factor of 1 25 in the table.