Roof Measuring Formula

8 inches and you have an 8 in 12 pitch.

Roof measuring formula.

L 30 feet h 12 feet 30 12 2 180 square feet. Next place your ladder against your house at the gable end. 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. Rafter rise run this formula is from the pythagorean theorem.

Don t use this as your only method of measuring. How to calculate your roof square footage first measure the length and width of each surface on the roof then multiply these values to get the square footage of that surface. 1 roof square 100 square feet. To find the squares divide the overall roof area by 100 and then round up.

If your roof measures 48 feet 15 m x 24 feet 7 3 m multiplying its length by its width would give you a square footage of 1 152 square feet 107 0 m 2. Make sure to document the number of chimneys skylights or other obstructions and include dormers in your measurements. For instance if the roof is 1550 square feet then it is 16 squares. To calculate the area of your roof first you ll need to calculate the pitch of it.

Use the following formula which also describes a right triangle. Climb to the top of your roof. 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. First use your measuring tape to measure 12 inches on your large level and make a mark at the 12 inch line.

So if you divide your answer of a product of length times height by two you will get the area of a triangle. It is often compared to slope but is not exactly the same. If this distance measures 4 inches you have a 4 in 12 pitch. This is only important for gable roofs as the calculator uses a specific formula to estimate roof run length of gable.

The length l times the height h of a triangle is twice its area a2. You can also calculate roof pitch even without using a roof slope calculator. Keep in mind that using google earth isn t going to give you a 100 percent accurate reading but it will give you a basic idea of the size of the roof for your calculations for the roofing materials. 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.

This is simply 100 square feet of roof. Pitch measurement method 1. Here are the equations you may use to solve for the length of the slope and the rafter. Measure both the width gable side and the length eave gutter side.

Just use it as a starting point and you ll have a fairly basic idea of what you re dealing. If its pitch is 6 in 12 a pitch multiplier of 1 12 multiplying 1 152 sq ft 107 0 m 2 by 1 12 would give you an overall square footage of 1 290 square feet 120 m 2.