Roof Truss Spacing Requirements

Truss span not greater than 36 feet.

Roof truss spacing requirements.

Metal roofs and pole buildings. 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. Putting the trusses into place. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches.

There are also three things that will affect roof truss spacing. The reality is there is no magic number. The live weight load of a roof basically comes down to the pressure. Most are spaced between 18 26 inches apart.

Maximum ground snow load of 70 psf. Minimum roof slope of 3 12. Once you ve calculated the number of trusses you will need you should purchase the lumber. 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.

Building width not greater than 60 feet perpendicular to the truss span. Rafter spacing rafters must be strong enough to hold the roof sheathing and the shingles. 36 long garage with 12 bays. 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.

If your local building authority has a rafter spacing code you may not space rafters wider than required by code. 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. Maximum design wind speed of 140 miles per hour 63 m s exposure b or c. Yet somewhere in the deep dark reaches of history lies the theory wood trusses must be spaced no more than 24 on center or maybe 48 or perhaps even eight or ten feet.

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. Maximum roof slope of 12 12. The dead weight load of a roof is all the different structural elements which can affect the amount of pressure that can be. Special inspection of the truss member bracing is also required where a truss clear span is 60 feet or greater 1705 5 1.

The standard spacing is 2.