Roof Measurement Formula

Total rise total run in feet x rise per foot the tan value for my 9 degree slope roof tan 9 0 1583.

Roof measurement formula.

You can assess this in two ways either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof. Measure both the width gable side and the length eave gutter side. In the united states a run of 12 inches 1 foot is used and pitch is measured as the rise of the roof over 12 inches. So if you divide your answer of a product of length times height by two you will get the area of a triangle.

On a ladder beside the roof place the level a foot or so up the roof hold it level and measure from the 12 inch mark on the level s bottom straight down to the roof. To calculate total rise if i knew the total run say we had made an on roof measurement we take the following steps. See the diagram. 1 roof square 100 square feet.

Pitch measurement method 1 1. Make sure to document the number of chimneys skylights or other obstructions and include dormers in your measurements. We ll use satellite imagery and trigonometry to calculate your roof s measurements. First measure the length and width of each surface on the roof then multiply these values to get the square footage of that surface.

If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. If your house has a hip roof then it does not matter which side is the length and which is the width for an accurate result. Calculate unit rise for the roof rise. It is often compared to slope but is not exactly the same.

Often you express roof pitch as the ratio between the rise and the run in the form of x 12. Includes result for hip valley factor slope factor and the roof slope in degrees. 8 inches and you have an 8 in 12 pitch. The length l times the height h of a triangle is twice its area a2.

This is only important for gable roofs as the calculator uses a specific formula to estimate roof run length of gable. If this distance measures 4 inches you have a 4 in 12 pitch. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. If you re going to use an area calculator you can do this separately for each level of the home to ensure a more accurate calculation.

Roof reports and wall reports made easy. Once you have this measurement you can then measure the footprint of the home and estimate the actual roof calculation based on the particular angle of the roof. Roof pitch refers to the slope which the rafter creates.