Roof Rafter Multiplier

You can also calculate roof pitch even without using a roof slope calculator. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement.

roof rack gutter protector roof hail damage claim process roofing coshocton ohio roof repairs cheshire roof repairs kelowna roof replacement on suv roofing contract must contain roof rack cox

Roof Pitch Multiplier What Is It How To Use

Roof Area Calculator Surface Area Multiplied By Pitch

Tfd Multiplier Table

Conversion Of Plan To Pitched Dimensions

How Much Does A New Roof Cost Complete Guide Roofpedia

Calculating Roofs Gables

Step 5 rafter size.

Roof rafter multiplier.

2 5 1 1 multiplier 2 75 m does not give the required span of 3 000 m. Measure the rise of your roof. Remember practice makes perfect. A roof pitch of 4 in 12 4 12 has a rise of 4 and a run of 12.

So the actual roof surface if it were laid down flat on the ground would be 1 118 times larger than the footprint of the roof. Rafter rise run this formula is from the pythagorean theorem. Use the following formula which also describes a right triangle. Read the rafter size in the left column of table 10 1 for the 3 3 m span chosen.

If the home measures 20 x 40 and has a 7 12 roof then to calculate the slope of the roof follow these steps. And for a roof with a slope of 6 12 that number 1 118 is your roof slope multiplier. Find the value of 7 12 from the roof slope multiplier table which is 1 16. 800 multiplied by 1 16.

Where a is the rise of the roof b is the run of the roof and c is the rafter hypotenuse of the triangle with side lengths a and b. Multiply step 1 and step 2 i e. The hip and valley factor is a number that is multiplied by the actual run horizontal distance of a common rafter to determine the length of a hip or valley rafter. Pitch rise run 1 5 6 25.

Students should use the sin cos and tan funtion rather then the multiplier table to calculate the length of the roof members. That gives you 5 590 square feet which is the actual area of the surface of the roof. Calculate the roof pitch as the proportion of rise and run. It takes some time to get use to these functions.

Take the area of the roof s footprint say it s 5 000 square feet and multiply 5 000 by 1 118. The next option in table 10 1 is 3 3 m. Calculate the rafter length substituting these values into the following formula. Multiply 20 and 40 which equals 800.

Divide the rise by the run the run is 12. Let s say it is equal to 1 5 m. The more you practise the more familiar you become using these functions. This indicates a 190 45 mm rafter size.

This table provides the hip and valley factor for common roof pitches as well as the underlying equation for the factor. Find the square root of the result. The slope of the roof provides the rise and the run to be plugged into the equation. The formula for the roof pitch multiplier comes from the famous pythagorean theorem.

Here are the equations you may use to solve for the length of the slope and the rafter. Rafter rise run 1 5 6 2 25 36 38 25rafter 38 25 6 18 m. This exceeds the rafter span proposed without using the multiplier so is suitable. 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.

Includes result for hip valley factor slope factor and the roof slope in degrees. Now solving for c in the equation above gives.