Hip roofs differ from standard peak roofs in that they have four sides, or faces, covered with roofing material. When planning to cover the hip roof with shingles, it is important to understand how to measure hip roofing to make sure you purchase enough material. Measuring is easy, once you understand that the hip roof is measured by face. Each face will form a simple triangle or parallelogram. You'll need to find the area of each face and add them together to know the entire area of the roof that needs to be shingled.
Set up a ladder to allow access to the roof, making sure that the feet of the ladder are resting on firm ground and the angle of the ladder to the roof is no less than 35 degrees. Have a helper hold the bottom of the ladder while you work from it to measure the roof.
Climb up to the roof and measure each face of the hip roof. For parallelogram-shaped faces, measure the length of the bottom edge of the roof, length of the top edge (the ridge) and length from the ridge straight down to the bottom edge. For triangular faces, measure the length of the bottom edge of the roof and the length from the ridge point straight down to the bottom edge.
Calculate the area of each face of the hip roof. For triangular faces, multiply the length of the base by the length from the ridge point to the bottom edge, then divide by 2. For parallelogram-shaped faces, first add the length of the ridge line to the length of the bottom edge. Divide that sum by 2, then multiply by the length from the ridge line straight down to the bottom edge.
Add the areas of the faces of the hip roof to find the total area of the hip roof in square feet.
Multiply the total square-foot area of the hip roof by 5 percent, or .05, for the amount of extra roofing material you'll need to allow for waste due to roofing error or damaged material. Add the waste amount to the total area to determine how much roofing material needs to be purchased overall.