How To Measure Roof Truss Size

Next you will need to use a roofing materials calculator.

How to measure roof truss size. Equation a2 b2 c2. Measure out 5 to 6 trusses at a time. 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. For example h sqrt 3 167 2 9 5 2 10 014 feet.

Hammer a nail in place to hook your measuring tape and space out the subsequent trusses every 2 feet or other designated spacing. Already having the rise will make it easy to determine the rafter length by loading the numbers into the equation chart. These are the base boards of your roof truss. 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.

Get the width of the structure you want to roof by measuring across the tops of the walls. 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. Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter.

Obtain the height of the gable by finding the difference in height between the top of the roof and the top of the structure. Outside of the u s a degree angle is typically used. How to measure roof trusses. Pitch measurement method 2 2.

Divide this number by 2. 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. Check that your footage measurements are within this range so you can start off on the right foot. 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.

8 inches and you have an 8 in 12 pitch. Starting at one end of the roof mark the first truss flush with the outside edge of a cap plate. Divide the length of the roof by two to determine how many trusses are needed. There are several variables to consider when determining the proper rafter size.

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. If this distance measures 4 inches you have a 4 in 12 pitch. C rafter length.

Use a level square and measuring tape. The truss is a framework consisting of rafters posts and struts which supports your roof. Simply input the surface area of the roof choose from one of the available options and you will get your first roofing estimate.