Roof Snow Load Tables

The sloped roof snow load p s shall be obtained by multiplying the flat roof snow load p f by the roof slope factor c s.

Roof snow load tables.

Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10. Let s look at the sample table below which shows maximum rafter spans for a snow load of 31 3 pounds per square foot psf. Flat roof snow loads p f the snow load that is applied to our structure is not the ground snow load but in most cases the flat roof snow load. In our case let s assume that our structure has a flat roof roof slope 5.

The actual design roof snow load is determined from the ground snow load sg provided in table 1 using a number of factors discussed in the ubc code and the asce 7 95. The shapes and spans shown here represent only a fraction of the millions of designs produced by alpine engineers. P s c s p f the thermal factor c t from table e 3 determines if a roof is cold or warm slippery surface values shall be used only where the roof s surface is unobstructed and sufficient space is. Span configuration and load conditions.

Lengthand widthof your roof. 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 calculate the weight of snow on a roof use the first two sections of our snow load calculator. Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size.

Depending on your region you may need to design for a maximum snow load of anything between zero to 65 pounds per square foot or roughly 0 3 kpa. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run. These factors include the effects of i terrain ii exposure iii thermal condition iv importance factor and v roof slope. Roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber spacing dimensions load and slope.

You can enter these values in any units you d like including meters and feet. Total load psf duration factor live load psf roof type 55 1 15 40 snow shingle 55 1 15 30 snow tile 47 30 snow 40 20 snow 1 25 20 construction or rain not snow load 55 1 15 40 snow. You need to supply the following information. Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.