Roof Slope Conversion Factor

In that case the multiplier is multiplied by the run of the rafter the horizontal distance that will be covered by the rafter.

Roof slope conversion factor.

Here are the equations you may use to solve for the length of the slope and the rafter. Use the following formula which also describes a right triangle. For example if you measure 4 inches the pitch of your roof is 4 12. Since pitch is the rise over a 12 inch run divide the run by 12 to get the multiplier in this case 120 12 10.

Degrees to roof pitch rise in run to see a table. The headache of using pythagoras and trigonometry can be spared by making use of these charts. On blue prints architects engineers usually display the pitch of a roof in the format shown on the image where number 4 represents a rise and number 12 represents a length. In essence a roof pitch chart is provided as a rough guide usually by a roofing company to help you see what the average roof pitches tend to be.

You could calculate the slope factor for every single roof pitch but as a public service many roofing companies provide slope factor charts. Multiply this amount by the slope factor 960 1 1180 1073 28. Also see our page quick reference. The roof pitch factor is also used to calculate the length of common rafters.

Multiply the roof length by the gable wall length 40 24 960. The following table shows how the same common roof slopes can be expressed using rise in run ratios degrees and percentages. For instance the ever last roofing company distributes a chart to the general public. Two most common methods 4 12 or 4 12 are used for marking the pitch of a roof.

Charts list the slope factor for various pitches usually from 1 12 to 12 12. A 10 slope roof should not be confused with a 10 pitch roof as a 10 slope roof means that the roof rises by ten inches for every foot of run. See below after the table for directions on how to convert any roof slope from one form to another even roof slopes not shown in the table. You can also calculate roof pitch even without using a roof slope calculator.

The total run is the distance from the peak to the edge of the roof which in this case is the total width divided in half which is equal to 10 feet or 120 inches. A roof pitch of 4 in 12 4 12 has a rise of 4 and a run of 12. The combination of two numbers are used to display or show the roof pitch. Rafter rise run this formula is from the pythagorean theorem.

This will give you the rise over run or pitch. The area of this roof 1073 3 sq. The area of a hip roof equals the area of a gable roof with the same dimensions. Usually they come in the form of a roof pitch diagram chart but other times it will be presented to you in a conversion format.

Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter.