Roof Load Width Verandah

The size of the roofing material is needed to calculate how much load the roof members and substructure need to support and therefore what size the underlying timber parts need to be.

Roof load width verandah.

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. Multiplied by 40 pounds per square foot equals 8 000 pounds. Roof beams 20 verandah beams 22 garage roof. Roof load width rlw and floor load width flw can be determined from as1684 or from the images below.

If you can source a beam of 6 5 mtrs long in one piece the size required would be 240 by 45 in f5 or f7 or mgp 10. For the pergola beams shown in illustration the roof load width is the dimension representing half the rafter span plus any rafter overhang. Pitching beams 23 common installation details 25 notches cuts and holes in beams bearers joists and rafters 26. This number represents the total load that your roof must carry.

Multiply the load per square foot by the total area of the roof. Verandah beams gl8 sheet roof 21 verandah beams gl8 tile roof 24 ridge beams f7 42mm sheet roof 25 ridge beams f7 42mm tile roof 28. Size grade continuous span verandah beams span values in mm roof load width mm 900 1200 1500 2400 3000 4000 5000 6000 140x35 f7 3600 3400 3100 2400 2200 1900 1700 1600 190x35 f7 4800 4500 4000 3200 2900 2500 2300 2100 140x45 f7 3900 3500 2800 2500 2200 2000 1800 5300190x45 f7 4800 3800 3400 3000 2700 2500. 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.

This video explains all the details of calculating the roof load width rlw for a variety of roofing types. The roof load width is half of the rafter span. For any particular load the allowable span of patio cover joists and beams depends on wood species and board size. When you refer to a beam s allowable span what you re really describing is the allowable spacing between posts.

If you have single span rafters of 4 8 mtrs the roof load width is 2 4 mtrs. The maximum overhang of house rafters or trusses shall not exceed 750 mm from outside of top plate to end of rafter truss. Size grade single span verandah beams span values in mm roof load width mm 900 1200 1500 2400 3000 4000 5000 6000 140x35 f7 25002300 2100 1800 1600 1500 1300 1200 190x35 f7 3400 3100 2900 2400 2200 2000 1800 1700 2700140x45 f7 2500 2300 2000 1800 1600 1500 1300 190x45 f7 3700 3400 3100 2700 2400 2200 2000 1800. For any species the allowable span generally increases as the joist or beam increases in size.

Refer to as1684 2 and 3 clause 2 6 4 for other configurations.