Consult local building codes for snow load capacity and reference the span tables for joists and rafters published by the american wood council awc as a general rule roofs that have a high human occupancy rate should be framed with rafters every 16.
Sloped roof snow load chart.
Roof snow load is defined as the weight of snow on the roof surface used in design of the building structure ibc 2012.
The snow load that is applied to our structure is not the ground snow load but in most cases the flat roof snow load.
To do this i use conservative too heavy dead loads and full snow loads regardless of pitch.
R802 10 2 and designed according to the minimum requirements of asce 7 10.
The minimum roof pitch for shedding snow is around 30 or a 6 12 or 7 12 slope although this is not a definite as the material of your roof the direction of the snow and wind are some factors that can affect whether or not snow will slide as roofs of as little as 10 have been reported to shed snow.
On multiple factors including.
There are also factors such as deflection elasticity and wood species that come in to play.
Ground snow load value.
For dead loads you are correct.
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.
In our case let s assume that our structure has a flat roof roof slope 5.
First figure out how deep the snow is piled up there.
If you live in the us our snow load calculator compares the total weight on your roof with the permissible load calculated according to the standards issued by the american society of civil engineers regarding the minimum design loads for buildings and other structures asce7 16.
If your roof is flat it is more likely to have snow load problems than if it is pitched.
You need to use a snow load formula for flat roofs.
The flat roof snow load is calculated using formula 7 3 1.
Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10.
It is determined based.
I ignore the slope.
For the design of an actual structure a registered and licensed professional should be consulted as per irc 2012 sec.
The easiest way is to push a yardstick into the snow on the roof selecting an area that looks typical of the overall snow depth.
All of the load cases required to fully design an actual structure are not provided by this calculator.
However in my practice i typically use the horizontal run of the roof for both types of load.
Roofs of steeper pitches will likely.
For locations where 0 pg 20 psf all roofs with a slope w 50 with w in ft shall have a 5 psf rain on snow surcharge.
P s c s p f.
