Psf Roof Load Shed

On the other hand snow that stayed on your roof for a few days will settle and while it seems that the cover gets thinner its weight doesn t change it s just the density that is different.

Psf roof load shed. See this floor construction video for details. Af pa s appendix a lists a variety of live and dead load combinations for floors ceilings and rafters. All loads are listed as pounds per square foot of horizontal projection footprint area. For roof live loads less than 20 pounds per square foot psf rafter spans and required e values tabulated for 20 psf shall be permitted to be adjusted in accordance with the fol lowing table.

Technically you should use the actual rafter length when adding up the weight of roofing materials. For example fresh snow is soft fluffy and light. For example appendix a indicates that one type of clay tile roof system has a live load value of 20 psf and a dead load value of 15 psf. Factors that influence.

However many agricultural buildings are built using a 20 psf snow load which would be expected to handle six feet of dry fluffy snow or one foot of wet heavy snow. For dead loads you are correct. Standard floors use 3 4 exterior grade plywood with double layer and pressure treated plywood optional. Reeds ferry shed floors are designed to carry a live load of 40 50 psf.

If there s wall board covered ceiling suspended from the underside of that floor the dead load increases to about 10 pounds per square foot. The density of snow and hence its load per square foot depends on the type of snow. On a roof with a slope greater than 4 to 12 the live load limit is typically adjusted downward from 20 psf to 15 psf to allow for the relatively greater dead load on the steeper roof. The loads are based on adjusted roof snow loads from the governing building code.

To do this i use conservative too heavy dead loads and full snow loads regardless of pitch. However in my practice i typically use the horizontal run of the roof for both types of load. Buildings wider than 8 have a double 2 6 center beam to ensure minimal deflection. For roof live loads of 12 psf or 16 psf.

Many factors influence how a system responds to loading. Here each square foot of roof system delivers 50 pounds of live load and 15 pounds of dead load 65 psf total to the structural support system. The design roof snow load for residential buildings in mn is set by state statutes and is 42 pounds per square foot psf in northern mn and 35 psf in southern mn.