Roof Rafter Spacing Australia

3 where rafters are equal to or exceed four times their breath blocking should be used to reduce distortion.

Roof rafter spacing australia.

This is set by the roof use you selected in the previous screen and cannot be modified. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. 2 for design parameters refer to figure 7 26. Tables such as those for rafters.

The maximum overhang of house rafters or trusses shall not exceed 750 mm from outside of top plate to end of rafter truss. Design of single span rafters in roofs in houses office buidlings schools and other structures. Pitching beams 23 common installation details 25 notches cuts and holes in beams. So the space between rafters can be greater without reducing the maximum span.

Loads are calculated in accordance with table 3 1 of as nzs 1170 1 2002. Half building width minus 1 2 ridge thickness. Wind classification n1 n2. A maximum roof pitch of 25 degrees is assumed.

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. Allow for ridge thickness when determining rafter run to outer wall. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches. Technical diagram span tables f7 rafters on page 35 30mm m aximum allow able sp ans mm sheet roof spacing mm rafter size 600 760 900 1000 1200 66 x 30 1250 1150 1050 1000 950 90 x 30 1650 1550 1550 1400 1300 138 x 30 2600 2300 2150 2000 1800 185 x 30 3000 2650 2450 2350 2150 230 x 30 3050.

If your local building authority has a rafter spacing code you may not space rafters wider than required by code. Rafters 12 ceiling joists 15 hanging beams member16 underpurlins 17 strutting beams 18 roof beams 20 verandah beams 22 garage roof. The same concept holds true for roof trusses. 1 refer to general notes for information that is relevant for all span tables.

The closer the rafters are to each other the stronger the roof will be. As a general rule roofs that have a high human occupancy rate should be framed with rafters every 16 structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes. For sheet roofed houses with 900 mm rafter spacing in wind classification n4 or c2 the minimum size of f5 or mgp 10 rafters or top chords shall be 90 x 45 mm. Use these two tables for roof rafters with a slope of 3 in 12 or less.

Pergola rafter spans for 600 mm and 900 mm spacing.