The exterior wall and the headers within will carry all loads from the mid point of the house between the supporting walls to the outside of the house including the roof overhang.
Roof load width meaning.
If you have single span rafters of 4 8 mtrs the roof load width is 2 4 mtrs.
Roofs are under a lot of pressure.
Spacing should be interpreted as the centre to centre distance between adjacent parallel members.
The north zone middle zone and the south zone are identified on the roof load zone map above.
Roof load width rlw and floor load width flw can be determined from as1684 or from the images below.
These diagrams may also be used to determine roof load width for floor joists.
If you like this video please subscribe to my channel.
In order to stay intact and in place a roof must be able to resist loads both permanent and temporary that are pushing.
This video looks at roof load width rlw.
The roof load width is half of the rafter span.
If the load is 100 psf the load to the beam would be 12 ft x 100 psf 1200 plf.
Tributary loading or tributary width is the accumulation of loads that are directed toward a particular structural member.
You would require three post to cover the 6 5 mtrs of beam length.
Load limits on the roof of a building.
The distance in this case is 12 ft 2 ft 14 ft.
Tributary width is 7 ft 5 ft 12 ft.
The north zone design live load equates to 40 pounds per square foot the middle zone equates to 30 pounds per square foot and the south zone equates to 20 pounds per square foot.
This downward imposed load on the home is also known as the snow load.
A built up roof for example will typically include the built up membrane itself with or without gravel as well as some kind of insulation and cover board which will vary in thickness from roof to roof.
The left wall has 7 ft of tributary width and would receive a load of 700 plf.
When it comes to estimating the weight of an existing roof field verification of the in place construction is necessary.
2attic loads may be included in the floor live load but a 10 psf attic load is typically used only to size ceiling joists adequately for access purposes.
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.
