Victor staley a building official in the town of brewster mass responds.
Griund versus roof load.
The calculator will tell you the pounds per square foot of snow.
Ground and roof snow loads for idaho by r.
Sheikh taheri snow loading is the most severe test of roof structures in many parts of the state of idaho.
The truss could be designed based on the assumption that the 25 psf roof snow load is a factored ground snow load in which case a ground snow load is back calculated using asce 7 based on the specified roof snow load pg 25 psf therein lies the problem with specifying only a roof snow load.
70 60 50 40 35 30 25 x0 7 x0 7 x0 7 x0 7 x0 7 x0 7 x0 7 roof snow load.
Ground snow load pg.
Roof loads are a downward vertical force on the home.
Table 1 1 page 3.
The roof shall be designed for the live load indicated in table r301 6 or the snow load indicated.
1 0 importance factor i.
Figure 7 1 pages 84 85 and table 7 1 page 92.
This downward imposed load on the home is also known as the snow load.
When discussing snow load with anyone it is crucial to have a clear understanding as to if the load is a ground or flat roof snow load.
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 load live load design is affected by the shape of the roof whether it is flat curved or pitched.
The north zone middle zone and the south zone are identified on the roof load zone map above.
Economical structural design in these areas requires an accurate prediction of the ground snow plus an understanding of how the snow is distributed on the roofs.
The flat roof snow load is calculated using formula 7 3 1.
Ground snow load might seem somewhat confusing until you read the basic premise that is identified in irc section r301 6 which states.
Then follow the instructions.
This issue of live load vs.
The determination of the drift load that is.
Length of roof upwind of the snow drift.
Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10.
After that you ll need to use a snow load calculator.
1 0 exposure factor ce.
Length of high roof lu.
It s quite easy to find one online.
Ground snow load or roof snow load snow load.
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.
49 42 35 28 24 5 21 17 5 assumed value thermal factor ct.
Weight of permanent.
Snow loads can be presented in two different ways.
