Unequal Sloped Roofs

This slope and skew calculator makes it easy by performing all of the necessary trigonometry for each hanger condition in the roof.

Unequal sloped roofs.

Drawing a superimposes the common rafters for the two roof pitches and illustrates the problem that occurs when roof layout starts at the outside edge of the exterior walls. The correct way to calculate the minor pitch king common rafter keeping all of the roof framing members in the roof planes is to use the major and minor plan angles. Using a tape measure make a pencil mark 12 inches from the end of a carpenter s level. Unequal pitch roof trigonometry calculating unequal pitched roofs is easy if you know what trigonometry functions to use.

Put on a pair of work gloves. Major pitch angle minor pitch angle minor run calculate. The formulas below use the law of sines to calculate the unknown length or angle. The rafter tools app irregular hip rafter function calculates the correct king common rafter length for unequal pitched hip rafter roofs.

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. Major pitch angle minor pitch angle span plate line difference calculate major minor runs theoretical plate line span theoretical span span plate line difference tan minor pitch angle plate line difference run span theoretical span major run. The formulas below use the law of sines to calculate the unknown length or angle. Then you ll be able to measure slope from an unfinished attic space under the roof.

You will have to chamfer the end of the ridge on a unequal pitched roof to keep the ridge in the roof plane alignment. Unequal pitch roof trigonometry calculating unequal pitched roofs is easy if you know what trigonometry functions to use. Create a roof slope using slope arrows. 9 tips to understand revit roofs.