Roof Measurement Formula

Often you express roof pitch as the ratio between the rise and the run in the form of x 12.

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. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. Includes result for hip valley factor slope factor and the roof slope in degrees. 1 roof square 100 square feet.

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. 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. This is only important for gable roofs as the calculator uses a specific formula to estimate roof run length of gable. Calculating an area of a triangle when estimating a roof.

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. We ll use satellite imagery and trigonometry to calculate your roof s measurements. Calculate unit rise for the roof rise.

If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Roof reports and wall reports made easy. 8 inches and you have an 8 in 12 pitch. Make sure to document the number of chimneys skylights or other obstructions and include dormers in your measurements.

It is often compared to slope but is not exactly the same. The length l times the height h of a triangle is twice its area a2. Pitch measurement method 1 1. 0 1583 rise run.

If this distance measures 4 inches you have a 4 in 12 pitch. Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run. See the diagram. 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.

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. Measure both the width gable side and the length eave gutter side. First measure the length and width of each surface on the roof then multiply these values to get the square footage of that surface.