Roof Live And Dead Loads

L r l o r 1 r 2.

Roof live and dead loads.

L design floor live load. 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 roof shall be designed for the live load indicated in table r301 6 or the snow load indicated. Ground snow load might seem somewhat confusing until you read the basic premise that is identified in irc section r301 6 which states.

Loads used in design load equations are given letters by type. Victor staley a building official in the town of brewster mass responds. Roof dead load framing sheathing asphalt shingles insulation drywall 10 exterior wall 2 4 framing sheathing siding insulation drywall 10 floor joist sheathing carpeting drywall 10 concrete wall 8 in. As a result the live load dead load and distribution of forces are different.

Where d is floor dead load. The floors walls roof columns stairs permanent equipment and any fixed decor constitute a static load that normally doesn t change over the life of the building. 1the load combinations and factors are intended to apply to nominal design loads defined as follows. Thick 150 concrete block wall 8 in.

H design lateral pressure for soil condition type. Thick 100 10 in. 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. Roof live load reduction.

Where l r shall not be less than 12 psf and not more than 20 psf. Lr maximum roof live load anticipated. Live loads on floors and roofs consists of all the loads which are temporarily placed on the structure for example loads of people furniture machines etc. Roof live load may be reduced by the following equation.

D dead load l live load l. From the general concept of load comes two major categories. Thick 125 12 in. How do they differ.

D estimated mean dead weight of the construction. Live roof load w wind load s snow load e earthquake load r rainwater load or ice water load t effect of material temperature h hydraulic loads from soil f hydraulic loads from fluids. This issue of live load vs. In short the dead load of a structure comprises its completed weight usually measured in pounds per square foot before it goes into service.