How To Measure Up For Roof Trusses

Use a tape measure to measure the entire width of your building.

How to measure up for roof trusses.

Divide the length of the roof by two to determine how many trusses are needed. 8 inches and you have an 8 in 12 pitch. 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. C rafter length.

If this distance measures 4 inches you have a 4 in 12 pitch. Use of manufactured roof trusses can dramatically cut labor costs when framing a gable roof compared to building rafters. Before you start cutting you first need to determine how long your roof rafters need to be and the angles at which you ll cut the top and bottom of the rafter. Set two ladders at each end of the area to be measured.

Pull a tape measure along the top plate of the house to determine the length of. Trusses can be constructed with smaller sized lumber than rafters and often their cost is not significantly higher than normal rafters. Step 1 find the total rise of the roof using the formula r ps 12 where r is the rise p is the pitch and s is the span. For example if the pitch is 4 and the span is 9 feet 6 inches r 4 9 5 12 3 167 feet.

For a 9 m 30 foot long roof a total of 15 trusses are needed. Trusses are generally secured 24. Hammer a nail in place to hook your measuring tape and space out the subsequent trusses every 2 feet or other designated spacing. In order to match up to an existing building there s a couple different measurements that are needed so that you will end up with a matching roof addition.

Converting that to feet and inches the rise is 3 feet 2 inches. Use a level square and measuring tape. Divide the length of the roof by two to determine how many trusses are needed. Measure out 5 to 6 trusses at a time.

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. Already having the rise will make it easy to determine the rafter length by loading the numbers into the equation chart. Pitch measurement method 1. Starting at one end of the roof mark the first truss flush with the outside edge of a cap plate.

Equation a2 b2 c2.