Roof Load Analysis

But isn t it more accurate to figure the weight of snow and roofing materials by measuring along the actual length of the rafter.

Roof load analysis.

Alternately there are now computer software programs that will both calculate your roof truss load and render a diagram of what the end result should be. 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. It is important to list live load dead load and total load separately because live load is used to compute stiffness and total load is used to calculate strength. Create a truss load diagram.

The north zone middle zone and the south zone are identified on the roof load zone map above. To calculate the weight of snow on a roof use the first two sections of our snow load calculator. You need to supply the following information. You can enter these values in any units you d like including meters and feet.

It is a good idea to fill in the resulting numbers from the truss load calculations on your roof truss sketch from the beginning. Roof load live load design is affected by the shape of the roof whether it is flat curved or pitched. 15 psf x 14ft 210 pounds per lineal foot. Length and width of your roof.

Roof loads are a downward vertical force on the home. 50 psf x 14ft 700 pounds per lineal foot. 910 pounds per lineal foot. If your roof is pitched enter the length and width of the flat area covered by the roof.

This downward imposed load on the home is also known as the snow load. I often see roof loads calculated based on the horizontal run of the roof.