Roof Load Analysis

You need to use a snow load formula for flat roofs.

Roof load analysis. In order for a roof truss load to be stable you need to assign two of your nodes on each truss to be support nodes. Roofs are under a lot of pressure. Loads on buildings and structures. The live loads used for the structural design of floors roof and the supporting members shall be the greatest applied loads arising from the.

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. 4for walls supporting heavy cladding loads such as brick veneer an analysis of earthquake lateral loads and combined axial loads should be considered. Step 4 determine the flat roof snow load. To do this i use conservative too heavy dead loads and full snow loads regardless of pitch.

For ground snow loads greater than 20 pounds per square foot the roof load is equal to. Technically you should use the actual rafter length when adding up the weight of roofing materials. Roof live loads largest roof loads typically caused by repair and maintenance pitch rise span lr 20 r1r2 12 lr 20 lr horizontal projection roof live load 16 r 1 r 2 live load reduction factors r 1 accounts for size of tributary area of roof column a t r 2 effect of the roof rise. Load limits on the roof of a building.

Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10. This means that one is a fixed node and the other is a rolling node. 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. For dead loads you are correct.

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. First figure out how deep the snow is piled up there. However in my practice i typically use the horizontal run of the roof for both types of load. However this load combination rarely governs the design of light frame construction.

In our case let s assume that our structure has a flat roof roof slope 5. In order to stay intact and in place a roof must be able to resist loads both permanent and temporary that are pushing. Axial forces from snow loads and roof live loads. If your roof is flat it is more likely to have snow load problems than if it is pitched.