Roof Live Load Psf

On a roof with a slope greater than 4 to 12 the live load limit is typically adjusted downward from 20 psf to 15 psf to allow for the relatively greater dead load on the steeper roof.

Roof live load psf.

For a larger map with greater detail refer to asce 7 98. The uniform design live load in unoccupied landscaped areas on roofs shall be 20 psf 0 958 kn m 2. Chapter 3 design loads for residential buildings. To correctly apply the values of the tables and the prescriptive methods of construction build ers must know the structural design criteria in the planning chapter of the code.

In other words on a steep roof less material would be stacked in a concentrated area at one time to avoid having it slide off. For roof live loads less than 20 pounds per square foot psf rafter spans and required e values tabulated for 20 psf shall be permitted to be adjusted in accordance with the fol lowing table. For example appendix a indicates that one type of clay tile roof system has a live load value of 20 psf and a dead load value of 15 psf. 3 20 residential structural design guide.

1607 3 uniform live loads the live loads used in the design of buildings and other structures shall be the maximum loads expected by the intended use or occupancy but shall in no case be less than the minimum uniformly distributed unit loads required by table 1607 1. Roof loads are a downward vertical force on the home. In my region on cape cod we have a ground snow load design of 25 psf which is a greater design load than the live load 12 psf to 20 psf over an entire roof system. Af pa s appendix a lists a variety of live and dead load combinations for floors ceilings and rafters.

Minimum design live load can be found in asce 7 table 4 1 or ibc table 1607 1. For roof live loads of 12 psf or 16 psf table multiply tabulated multiply required number span by e value by 12 psf 16 psf 12 psf 16 psf. The uniform design live load for occupied landscaped areas on roofs shall be determined in accordance with table 1607 1. 1607 13 4 awnings and canopies.

6 2015 home builders jobsite codes note the roof is designed for the roof live load not more than 20 psf or the snow load whichever is greater. Roof load live load design is affected by the shape of the roof whether it is flat curved or pitched. This downward imposed load on the home is also known as the snow load. 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.