Normal Roof Dimensions

Although the standard panel lengths mirror the lengths of common roof framing lumber rafter lengths rarely conform to the panels precise 2 foot increments.

Normal roof dimensions.

Roof pitch is expressed as a ratio of the amount of the roof s vertical rise over a corresponding horizontal distance called the run pitch is written assuming a run of a foot or 12 inches so the ratio describes how much the roof rises for every foot of its run. It will support roof. Standard home improvement stores often stock lengths up to 12 or 16 feet. Standard roofing panel length typically begins at 8 feet long and increases in 2 foot increments until about 24 feet.

Length and width standard lengths for corrugated roofing are 8 10 and 12 feet. Next you will need to use a roofing materials calculator. Never attach roof sheathing with staples. Check that your footage measurements are within this range so you can start off on the right foot.

For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended. The width varies greatly depending on the style of roofing. The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that. A common range is given from 1 12 to 4 12 whereas conventional dimensions vary from 4 12 to 9 12 but the steep roofing technique follows slope above 9 12 with additional fasteners.

The typical thickness range for sheathing is 3 8 to 3 4 inch. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame. Sheathing should be a minimum of 19 32 inch thick.

Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch. The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7. Keep in mind that the average size of a roof is 1 700 square feet so your total will likely be 10 higher or lower than this figure. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.

8d ring shank nails should be used instead.