Live Load On Flat Roof

Calculating the load on a flat roof is a challenging task for the layperson that involves knowledge of building materials their weights and local building codes.

Live load on flat roof.

D dead load l live load l r live roof load w wind load s snow load e earthquake load r rainwater load or ice water load. Roofs of buildings used for promenade or incidental assembly purposes shall be designed for a minimum load of 400 kg m2 4 kn m2 or heavier it required. For roofs that are flat and with ground snow loads lower than 20 pounds per square foot the roof snow load is equal to 70 of the product of the exposure thermal and importance factors and the ground snow load. Roof load live load design is affected by the shape of the roof whether it is flat curved or pitched.

Where snow isn t a problem the live load can come from people working on the roof and any equipment they take on to the. Axial forces from snow loads and roof live loads should usually not be considered simultaneously with an extreme wind load because they are mutually exclusive on residential sloped roofs. Live loads on roofs table 1 3 gives lives loads on flat roofs sloping roofs and curved roofs. Used but they typically defined the load cases or combination stress or strength limits and deflection limits.

The live load on a roof is the weight of any temporary objects on the roof. Further in most areas of the united states design winds are produced by either hurricanes or thunderstorms. For ground snow loads greater than 20 pounds per square foot the roof load is equal to. This downward imposed load on the home is also known as the snow load.

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. The standard guide in the u s the asce 7 05 lists weights and stresses for all building materials expressed in pounds per square foot. Ordinary flat pitched and curved roofs and awnings and canopies other than of fabric construction supported by a skeleton structure are permitted to be designed for a reduced uniformly distributed roof live load l r as specified in the following equations or other controlling combinations of loads as specified in section 1605 whichever produces the greater load effect. Step 4 determine the flat roof snow load.

Load types loads used in design load equations are given letters by type.