Roof Load Width Explained

House roof framing loads.

Roof load width explained.

These diagrams may also be used to determine roof load width for floor joists. The span would be 11 5 3 4. The snow load is treated as a live load when you use af pa s tables. Most commonly the roof s internal support structure is composed of a fairly complicated system of structural elements designed to manage the load from the roof.

The entire roof load is supported by load bearing walls which in turn transfer weight to the foundations of your home. So consider a simple gable roof on a 24 foot wide ranch framed with 2 6 exterior walls and a 1 1 2 ridge. Spacing should be interpreted as the centre to centre distance between adjacent parallel members. Roofs are under a lot of pressure.

Roof load width rlw and floor load width flw can be determined from as1684 or from the images below. Any areas between the wall corners that are not included within zone 5. Used for roof overhang area along the perimeter of zone 3. 2 you must determine the snow load for your region.

Trusses struts and props. 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. Load limits on the roof of a building. This information is found in the code book.

Roof pitch refers to the amount of rise a roof has compared to the horizontal measurement of the roof called the run. Used for roof overhang area along the perimeter of zone 2. Has the highest load. In order to stay intact and in place a roof must be able to resist loads both permanent and temporary that are pushing.

The north zone middle zone and the south zone are identified on the roof load zone map above. This downward imposed load on the home is also known as the snow load.