Attic Dead Load

Storage space dead load of partitions 20 lbs.

Attic dead load.

Unless expressly built so an attic s joists are meant for carrying the load of the ceiling below and related elements collectively known as the dead load. Dead loads are things that do not move. A the top and bottom chord dead load. As a result the live load dead load and distribution of forces are different.

Dead load of attic floor when floored 20 lbs. Analysis of an attic truss requires multiple load cases with multiple duration factors. The truss shown below is known as an attic truss or a room in attic truss. C determine the total load and proper load duration.

A typical wood frame floor covered with carpet or vinyl flooring has a dead load of about 8 pounds per square foot. It is also an indeterminate structure with a non triangulated web area which interrupts the normal flow of forces thru the truss. Boxes trunks suitcases etc. Since it is possible to use the attic for storage the live load of the attic floor is set at 20 psf according to code.

Live loads are people and animals and tangentially the things used by people. Most houses attics are built without flooring and are not designed to carry the heavy load of finished space. The values for dead loads in table 3 2 are for commonly used materials and constructions in light frame residential buildings. Unlike the trussed roof live load and dead load of the rafters and ceiling joists must be accounted for as separate systems.

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. B the top chord live include snow load as a live load and bottom chord live load. This type of truss carries a combination of roof l r or s and floor l loading in addition to the standard top and bottom chord dead loads. Of floor area dead load of partitions 20 lbs.

Dead load of first floor ceiling not plastered 10 lbs. Of floor area dead load on second floor 20 lbs. The ceiling load may include items like drywall ducts recessed lights bathroom fans and attic insulation. In rare cases especially in new construction homes the attic may have been built unfinished with the correct flooring in place with the idea that the homeowner could later on finish the space.