Attic Joists Load

Design live loads will vary based on a number of factors but at a minimum 10 psf live load for attics without storage 20 psf live load with limited storage and 30 psf for habitable attics.

Attic joists load.

Roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber spacing dimensions load and slope. Ft dead load of roof of wood shingle construction 10 lbs. The joists must have enough strength to support the load anticipated in the future as well. Standard joist spacing for the installation of attic flooring materials is 16 inches on center oc meaning the distance from the center of one joist to the center of the next joist is 16 inches.

This scheme is predicated on achieving serious load carrying connections well thought out and installed a 35 or l clips should to it at all joints. Tie to roof rafters at peak tie to ceiling joists roof rafters to ceiling joists at the eaves. Live load on attic floor local requirements. Use six 10d nails with plywood gussets or six 16d nails with 2x4s half into each 2x6 joist.

Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. Attics that have no flooring 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. Raised floors are hardier under the foot with scope for plumbing insulation heating equipment wiring and more. In fact a raised plywood attic floor over insulation lowers your home s energy cost.

Where they connect to both the top and bottom joists each gusset pair will transfer approximately 100 pounds that s 50 psf of floor load times the 3 foot gusset spacing times the 16 inch joist spacing divided by the two joists. This sample table gives minimum floor joist sizes for joists spaced at 16 inches and 24 inches on center o c for 2 grade lumber with 10 pounds per square foot of dead load and 40 pounds of live load which is typical of normal residential construction. Joist span bridging girder load width half joist span live load on roof local requirements for wind and snow. The ceiling joists create a truss to begin with i m suggesting adding another member to the truss.

The ceiling load may include items like drywall ducts recessed lights bathroom fans and attic insulation.