How To Work Out Flat Roof Percentage

Calculate the rafter length substituting these values into the following formula.

How to work out flat roof percentage.

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. The most precise way to find the roof s slope is by measuring it from the underside. For ground snow loads greater than 20 pounds per square foot the roof load is equal to 70 of the product of the exposure thermal and importance factors the ground snow load and 20 pounds. Measure the rise of your roof.

If you have any concerns as you are determining your flat roof snow load consult with a structural engineer or roofing specialist. Extend it upward so it is perpendicular to the level. Working on one of the previous example lets assume we have a slope that has a run of 10m with a rise of 500mm. Locate the level s 12 inch mark.

I ve checked the room dimensions up and down left and right and i can t get anywhere near the threshold but i m nervous. I just want to check how this is calculated. How to work out slope percentage if we want to work out the percentage of a slope you first must ensure you convert the units so they are the same similar to working with the ratios above. Pitch rise run 1 5 6 25.

Rafter rise run 1 5 6 2 25 36 38 25rafter 38 25 6 18 m. Here s what i did. Use a level against the underside of the rafter you re measuring to get the most accurate value. If this distance measures 4 inches you have a 4 in 12 pitch.

Measure the vertical distance from roof to level. Calculate the roof pitch as the proportion of rise and run. Let s say it is equal to 1 5 m. Move the tape measure along the the roof until it hits the level at exactly the 12 inch mark.

Access one of the rafters then take the measurement this way. Hold the 0 mark of the tape measure against the roof.