Roof Truss Span Distance

To achieve maximum indicated spans trusses may require six or more panels.

Roof truss span distance.

The roof truss spacing standard is important because eighty percent of new homes are built with standard pre fabricated trusses. 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. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2. For instance if you are spacing your trusses 18 inches apart make a mark 18 inches from the edge.

Already having the rise will make it easy to determine the rafter length by loading the numbers into the equation chart. After the braces are in place you will mark the distance from the edge of the building to where you would like to attach your first truss. Equation a2 b2 c2. These standards are as follows.

Bt b tc 6 6 common truss configurations for the most widely designed roof shapes. Contact your localalpine trussmanufacturerorofficeformoreinformation. Trusses with an asterisk that exceed 14 in height may be shipped in two pieces. Span also known as gable width this is based on the total footprint of the house and refers to the distance between two exterior walls.

This means that if you re in charge of repairing or installing roofing trusses you ll be expected to hold to these standards. Mono used where the roof is required to. Standard roof truss spacing.