Roof Load Analysis

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 analysis.

15 psf x 14ft 210 pounds per lineal foot. I often see roof loads calculated based on the horizontal run of the roof. But isn t it more accurate to figure the weight of snow and roofing materials by measuring along the actual length of the rafter. Create a truss load diagram.

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. You can enter these values in any units you d like including meters and feet. 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. 50 psf x 14ft 700 pounds per lineal foot.

910 pounds per lineal foot. It is a good idea to fill in the resulting numbers from the truss load calculations on your roof truss sketch from the beginning. You need to supply the following information. This will help you keep track of them while installing each triangular truss and it can be a handy reference for which nodes you have assigned as load bearing fixed and rolling.

Length and width of your roof. 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. Roof loads are a downward vertical force on the home.

Roof load live load design is affected by the shape of the roof whether it is flat curved or pitched. Thus as the roof gets steeper the rafter gets longer and the weight of roofing materials increases.