Roof Snow and Live load appear on the design report. Is this causing members to fail?

When designing a floor member that is carrying a roof load, the transferred load from the roof is reporting both Snow Load at 115% and Roof Live Load at 125%.

The concern may be that:

  • Two loads (Live and Snow) from the roof are being transferred,
  • That the two loads are being added to each other incorrectly creating a larger than real load for the design.

BC Framer® software Building Code does have input for both Snow Load and Roof Live Load. Minimum Roof Live Load is 10 PSF. Both loads are distributed and transferred down the building model. Both loads are reported on the Design Report. However the two loads are not added to each other, they are run in separate load cases. The load case which produces the controlling result is reported on the Design Report. This will be what the controls and reactions reflect.

To check this, design two members with a snow load that are identical. One contains a minimum 10 PSF Roof Live Load and the second contains a Roof Live just less than the snow load. The Design Results from both designs are identical. 

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