Roof Truss Span Distance

Typical roof truss.

Roof truss span distance.

Standard roof truss spacing. 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. These standards are as follows. C rafter length.

Mono used where the roof is required to. For instance if you are spacing your trusses 18 inches apart make a mark 18 inches from the edge. 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. 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.

Overhang this is the extra part that extends beyond the exterior wall of the home. 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. Contact your localalpine trussmanufacturerorofficeformoreinformation. The roof truss spacing standard is important because eighty percent of new homes are built with standard pre fabricated trusses.

Equation a2 b2 c2. This means that if you re in charge of repairing or installing roofing trusses you ll be expected to hold to these standards. To achieve maximum indicated spans trusses may require six or more panels.