If possible, have a helper steady the ladder from ground level while you work. If you’re working with a rectangular roof, be sure to measure both the longer and shorter hips separately. You’ll need both sets of dimensions in order to accurately tab out your roof’s total square footage. Jot down eat dimension separately in a notebook or scrap sheet of paper. Don’t forget to label which dimension is which. It’s not necessary to measure the vertical sides of your roof, or to figure out its slope. To find the square footage of a hip roof, you just need to calculate the area of each of its faces. For this, you’ll use the same formula that you would use to find the area of an ordinary triangle or trapezoid. [2] X Research source
If the bottom edge of one triangular roof face is 30 feet (9. 1 m) long and the distance between the peak and the bottom edge is 18 feet (5. 5 m), the area of the face is 270 square feet (25 m2). If one face of a trapezoidal roof is 30 feet (9. 1 m) long at the bottom and 24 feet (7. 3 m) long at the top with a 14 ft (4. 3 m) height differential, its cumulative area would be 378 square feet (35. 1 m2).
If you’re trying to work out the total area of the roof of a square building, simply multiply the area of one of the identical faces by 4. Keep in mind that trapezoidal roofs have 2 trapezoid-shaped faces and 2 triangular faces, which means you’ll need to apply both formulas in order to add up the area correctly. [8] X Research source
For reference, a standard package of shingles contains enough materials to cover 33. 3 square feet (3. 09 m2) of roofing. [9] X Research source You may not end up using every last bit of your chosen roofing material when it’s all said and done, but it’s better to have too much than not enough.
You can find laser measuring tools and other specialty measuring devices at any major hardware store or home improvement center. [11] X Research source If you already know the exact dimensions of the structure you’re roofing or have access to the original building plans, it’s okay to skip this step and work from recorded measurements. Write down and label each of your measurements clearly as you map out the size and shape of your roof. Sketching out a rough diagram of the roof can help you visualize how each of the components will fit together. A good piece of 3D construction software will guarantee even more precise results. [12] X Research source
The term “slope” refers to the steepness of the angle of each of the roof’s faces. “Slope” is sometimes used interchangeably with “pitch,” though pitch more accurately describes the steepness of the roof in relation to its overall size. Hip roofs often have relatively gentle slopes. A hip-style roof with a high slope is known as a tented roof. [14] X Research source
If the structure you’re building the roof for is 12 feet (3. 7 m) wide, the common rafters would have a run of 5 feet (1. 5 m), 11 −1⁄4 inches (27 cm). The common rafters are the vertical boards that serve to mark the ends of the ridge board. They run from the ridge (the uppermost edge of the roof) down to the exterior walls of the structure. [16] X Research source
The exact length of each of your rafter boards will depend on the particular slope you’ve selected for your roof. The king common rafters are also sometimes known as “crown end rafters. ”
You may need to use temporary braces to stabilize your hip rafters until you can nail them down once you actually begin building. [19] X Research source
Measure from the top of the last rafter you set to the top of the next one in the row to figure out how much to wood to take off of each board. For overhanging roofs, you’ll also need to cut birdsmouth notches into the rafters at the point where they’ll meet the exterior wall of the structure. [21] X Research source
