Roof Layout Formula

Minus ridge thickness to allow for ridge becoming pole plate roof peak will be slightly higher ridge thick must be same.

Roof layout formula.

We included a roof pitch chart below the 7 12 example image and the calculator below that. Pitch also has its own denotation determined by the rise in inches in 12 inches. The truss is a framework consisting of rafters posts and struts which supports your roof. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally.

It is often compared to slope but is not exactly the same. If this isn t practical then perform the same measurement on the underside of the roof. Roof volume top of wall plate to under rafters 1346 75 ft top of wall plate to top of rafters 1868 05 ft. Enter the extension wall length into wall length and double the extension wall width then minus ridge thickness into the wall width entries.

Overhang the overhang should be measured from the outer edge of the exterior wall to the furthest point of the rafter. Roof pitch roof pitch is the measurement of a roof s vertical rise divided by its horizontal run. Outside top plate edge to ridge top edge common 10 11 3 4. H b x tan α 2 common rafters b 2 x cos α hip rafters h 2 b 2 2 hip roof area 2 x common rafters x roof base length where h roof rise b roof base width α roof pitch tan tangent cos cosine.

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. Having the correct pitch is important. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. Which is equal to 1 4 or 1 3 the total span of the building not counting any overhang.

Porch roof extensions for hip roof porch extensions from an existing building wall you can use half the calculator results. Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak. For instance a 4 12 pitch denotes a roof rising 4 inches for each 12 inches. The important point to keep in mind when you use your truss calculator is that every truss calculation is completely unique and is based on the size of your roof and its specific dimensions.

Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. Here the overhang is 320 13 inches. Here the number is 941 86 inches. Pitch for a gable roof the most common is generally 1 4 or 1 3.