Roof Truss Spacing Requirements

Putting the trusses into place.

Roof truss spacing requirements.

There are also three things that will affect roof truss spacing. The dead weight load of a roof is all the different structural elements which can affect the amount of pressure that can be. Maximum roof slope of 12 12. This makes the roof ready for decking or sheetrock.

The standard spacing is 2. Building width not greater than 60 feet perpendicular to the truss span. Maximum design wind speed of 140 miles per hour 63 m s exposure b or c. The trusses should be a little longer than the exact width to allow for overhang and you will need sufficient trusses to mount across the length.

Rafter spacing rafters must be strong enough to hold the roof sheathing and the shingles. Metal roofs and pole buildings. Maximum ground snow load of 70 psf. The reality is there is no magic number.

If the overhang is more than around 2 6 it will require a 2 6 top cord for the tail section to handle that amount. 36 long garage with 12 bays. Special inspection of the truss member bracing is also required where a truss clear span is 60 feet or greater 1705 5 1. Flat the most economical flat truss for a roof is provided when the depth of the truss in inches is approximately equal to 7 of the span in inches.

Most are spaced between 18 26 inches apart. If your local building authority has a rafter spacing code you may not space rafters wider than required by code. Truss spacing the distance between trusses. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches.

Trusses spanning 60 feet or more require a registered design professional to design the temporary installation restraint bracing and the permanent individual truss member restraint bracing 2303 4 1 3. Once you ve calculated the number of trusses you will need you should purchase the lumber. Although the standard spacing of roof trusses may be the same as that of rafters with 24 inch spacing being a common option the design of a truss may allow for the use of a lower grade of lumber than would be required for rafters with comparable spacing and span. Most economical when the difference in slope between the top and bottom chords is at least 3 12 or the bottom chord pitch is no more than half the top chord pitch.

Truss span not greater than 36 feet.