How To Measure Roof Truss Size

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.

How to measure roof truss size.

How to measure roof trusses. 8 inches and you have an 8 in 12 pitch. Converting that to feet and inches the length of the top chord is 10 feet 3 16 inch. The truss is a framework consisting of rafters posts and struts which supports your roof.

For example h sqrt 3 167 2 9 5 2 10 014 feet. This sizing guide for roof rafters will help determine what you need for your small project. Hammer a nail in place to hook your measuring tape and space out the subsequent trusses every 2 feet or other designated spacing. Simply input the surface area of the roof choose from one of the available options and you will get your first roofing estimate.

Already having the rise will make it easy to determine the rafter length by loading the numbers into the equation chart. Use a level square and measuring tape. Check that your footage measurements are within this range so you can start off on the right foot. C rafter length.

Calculate the length of the top chord with the formula h sqrt r 2 s 2 where h is the length of the top chord measuring from either side of the chord from plumb cut to plumb cut. Equation a2 b2 c2. Next you will need to use a roofing materials calculator. In the united states a run of 12 inches 1 foot is used and pitch is measured as the rise of the roof over 12 inches.

Measure out 5 to 6 trusses at a time. These are the base boards of your roof truss. Obtain the height of the gable by finding the difference in height between the top of the roof and the top of the structure. Set two ladders at each end of the area to be measured.

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. Trusses are generally secured 24. Starting at one end of the roof mark the first truss flush with the outside edge of a cap plate. Divide this number by 2.

There are several variables to consider when determining the proper rafter size. Divide the length of the roof by two to determine how many trusses are needed. Outside of the u s a degree angle is typically used. Get the width of the structure you want to roof by measuring across the tops of the walls.

The important point to keep in mind when you use your truss calculator is that every truss calculation is completely unique and is based on the size of your roof and its specific dimensions. Pitch measurement method 2 2. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter.