Roof Live Load Requirements

3 20 residential structural design guide.

Roof live load requirements.

The minimum design roof snow load. The north zone middle zone and the south zone are identified on the roof load zone map above. 0 9d 1 0w a load factor of 1 6 when adding to load 7. The roof live load used in the design shall be indicated 780 cmr 1607 11.

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. 1603 1 1 floor live load. 1 2d 1 0w l 0 5 l r or s or r 5. The ground snow load p shall be indicated.

In areas where the ground snow load is less than 15 psf the minimum roof live load refer to section 3 4 is usually the controlling rgavity load in roof design. Minimum uniformly distributed live loads. 0 9d 1 0e effect or 0 9 when resisting the load when permanent. The roof live load used in the design shall be indicated for roof areas section 1607 12.

Also whether live load reduction has been applied. This modification makes two key changes. 1603 1 3 roof snow load. The dead load of a typical asphalt shingled wood framed roof is about 15 pounds per square foot.

Schilke civil agricultural engineering montana state university august 1989. An nahb proposal amended the 2015 ibc to restore the traditional 20psf roof live load requirement for porches patios or canopies on one and two family dwellings but the issue remains for multifamily buildings. Roof connection details roof live load engineered framing specs details for fired rated structural elements flood hazard requirements base flood elevation certification flood proofing damp proofing. For each type of live load used in the design.

The load increases with the use of heavier roofing material. Or s or r l or 0 5w dead load d in 1 through 5 and 7. A clay tiled roof may have a dead load. The uniformly distributed concentrated and impact floor live loads used in the design and where they are applied shall be indicated.

For a larger map with greater detail refer to asce 7 98. 1603 1 3 roof snow load data. In areas where the ground snow load p exceeds 10 pounds per square foot psf 0 479 kn m2. In areas of the state outside of certified local government jurisdictions the design snow load shall be based on the ground snow loads developed in snow loads for structural design in montana authored by f f.

1603 1 2 roof live load. Chapter 3 design loads for residential buildings.