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.
Roof snow load tables.
Framing table for maximum roof rafter spans.
For roof live loads of 12 psf or 16 psf table multiply tabulated multiply required number span by e value by.
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.
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.
You need to supply the following information.
In our case let s assume that our structure has a flat roof roof slope 5.
Lengthand widthof your roof.
The loads are based on adjusted roof snow loads from the governing building code.
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.
Span configuration and load conditions.
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.
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.
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.
The shapes and spans shown here represent only a fraction of the millions of designs produced by alpine engineers.
Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size.
To calculate the weight of snow on a roof use the first two sections of our snow load calculator.
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.
These factors include the effects of i terrain ii exposure iii thermal condition iv importance factor and v roof slope.
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.
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.
