Roof Snow Load Tables

To calculate the weight of snow on a roof use the first two sections of our snow load calculator.

Roof snow load tables.

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. Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10. You need to supply the following information. Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size.

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. 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. You can enter these values in any units you d like including meters and feet. The loads are based on adjusted roof snow loads from the governing building code.

The shapes and spans shown here represent only a fraction of the millions of designs produced by alpine engineers. 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. In our case let s assume that our structure has a flat roof roof slope 5. Span configuration and load conditions.

Lengthand widthof your roof. Framing table for maximum roof rafter spans. 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. 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.

For roof live loads of 12 psf or 16 psf table multiply tabulated multiply required number span by e value by. 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. 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. These factors include the effects of i terrain ii exposure iii thermal condition iv importance factor and v roof slope.