Roof Snow Load Is Dead Load

In my region on cape cod we have a ground snow load design of 25 psf which is a greater design load than the live load 12 psf to 20 psf over an entire roof system.

Roof snow load is dead load.

R 1 1 for a t less than or equal to 200 psf r 1 1 2 0 001 a t for between 200 psf and 600 psf. 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. In other words on a steep roof less material would be stacked in a concentrated area at one time to avoid having it slide off. The design spectral acceleration parameters are s ds 0 28 and s d 1 0 11.

Where d is floor dead load. D dead load l live load l r live roof load w wind load s snow load e earthquake load r rainwater load or ice water load. Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10. Ignore the weight of cladding.

In our case let s assume that our structure has a flat roof roof slope 5. Load types loads used in design load equations are given letters by type. The snow load that is applied to our structure is not the ground snow load but in most cases the flat roof snow load. 3 3 dead loads dead loads consist of the permanent construction material loads comprising the roof floor wall and foundation systems including claddings finishes and fixed equipment.

The roof dead load is 32 psf the floor dead load including the partition load is 80 psf and the flat roof snow load is 40 psf. Sloped roofs especially steeply sloped roofs such as the a frame styles common in very snowy climates shed snow very efficiently and carry a much lower load than flat roofed structures. L r l o r 1 r 2. Where l r shall not be less than 12 psf and not more than 20 psf.

Used but they typically defined the load cases or combination stress or strength limits and deflection limits. Roof live load may be reduced by the following equation. 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 flat roof snow load is calculated using formula 7 3 1.

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.