For low rise buildings an abbreviated method is in bs6262 3 2005.
Snow load on roof uk.
Obtain the recorded snow load the maximum load expected to accumulate on the ground for your area.
Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10.
You can shovel out a cubic foot of snow from the roof place it in a container and quickly weight it on a scale.
In our case let s assume that our structure has a flat roof roof slope 5.
Thus snow weighing 10 pounds per cubic foot and at a depth of 18 inches on a roof is exerting 15 pounds of pressure per square foot.
For roofs that are flat and with ground snow loads lower than 20 pounds per square foot the roof snow load is equal to 70 of the product of the exposure thermal and importance factors and the ground snow load.
Then measure the depth of snow on the roof and multiply it by the weight of a cubic foot of that snow.
A person needing to access the roof in order to repair items.
Wind snow and rain.
Typically for the uk the average design wind load is 1200 n m2 and the snow load 600n m2 however using the average may cause the glass to be over specified or even worse underspecified for the task.
Ground snow load s s.
Rain load s r.
Importance factor i s.
The roof should be tied down to the structure to stop it from lifting in times of strong winds.
The uniformly distributed snow loading on the roof is obtained by multiplying the ground snow load by the appropriate snow load shape coefficient see section 5 3 of bs en 1991 1 3 and annex b of bs en1991 1 3.
The design wind load can be calculated using bs6399 2.
And imposed loads on buildings.
Flat roof snow loads p f.
The scope of bs en 1991 1 3 is limited to snow loads only c in accordance with clause 3 3 2 1 of bs en 1991 1 1 roofs of buildings particularly domestic roofs where the allowed imposed loads cover maintenance only imposed loads need not be considered to act simultaneously with snow loads and or wind actions.
This would include tiles battens felt insulation etc.
For ground snow loads greater than 20 pounds per square foot the roof load is equal to 70 of the product of the exposure thermal and importance factors the ground snow load and 20 pounds.
Measure the horizontal distance from eaves to the ridge the point where the roof is tallest and record the result labelled as run for example consider a roof with a run of 12 2 metres 40 feet.
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.
