Roof Live Load Psf

This downward imposed load on the home is also known as the snow load.

Roof live load psf.

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. The uniform design live load for occupied landscaped areas on roofs shall be determined in accordance with table 1607 1. 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. 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.

The uniform design live load in unoccupied landscaped areas on roofs shall be 20 psf 0 958 kn m 2. 3 20 residential structural design guide. 1607 13 4 awnings and canopies. For a larger map with greater detail refer to asce 7 98.

Af pa s appendix a lists a variety of live and dead load combinations for floors ceilings and rafters. 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 load live load design is affected by the shape of the roof whether it is flat curved or pitched. 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.

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. Roof loads are a downward vertical force on the home. Minimum design live load can be found in asce 7 table 4 1 or ibc table 1607 1. Chapter 3 design loads for residential buildings.

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 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. 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. The north zone middle zone and the south zone are identified on the roof load zone map above.