How To Measure For A Roof Truss

Calculate the height of a common truss using the building width and the slope of the roof.

How to measure for a roof truss.

This online truss calculator will determine the all in cost of your truss based on key inputs related to the pitch width and overhang of your roof. Use a level square and measuring tape. For example a roof with a span of 20 ft and a rise of 7 feet needs rafters that are the square root of 400 49 21 2 feet. Depending on your roof slope add 4 to 5 inches for heel height.

Hammer a nail in place to hook your measuring tape and space out the subsequent trusses every 2 feet or other designated spacing. Trusses can be constructed with smaller sized lumber than rafters and often their cost is not significantly higher than normal rafters. Hook your tape measure on the king post to make marks at 2 feet 10 1 2 inches and 5 feet 9 inches on both the top and bottom chords. On a ladder beside the roof place the level a foot or so up the roof hold it level and measure from the 12 inch mark on the level s bottom straight down to the roof.

Trusses are generally secured 24. Already having the rise will make it easy to determine the rafter length by loading the numbers into the equation chart. Pull a tape measure along the top plate of the house to determine the length of. If this distance measures 4 inches you have a 4 in 12 pitch.

Pitch measurement method 1 1. Starting at one end of the roof mark the first truss flush with the outside edge of a cap plate. If you can t get the heel height most residential trusses will have a 3 top cord. Set two ladders at each end of the area to be measured.

Position the truss on the floor with the bottom chord near you and the king post on the right. Flat the most economical flat truss for a roof is provided when the depth of the truss in inches is approximately equal to 7 of the span in inches. Measure out 5 to 6 trusses at a time. How to measure roof trusses.

Equation a2 b2 c2. Be sure the tape measure is parallel to the bottom chord when measuring. Use of manufactured roof trusses can dramatically cut labor costs when framing a gable roof compared to building rafters. 8 inches and you have an 8 in 12 pitch.

Most economical when the difference in slope between the top and bottom chords is at least 3 12 or the bottom chord pitch is no more than half the top chord pitch.