Attic joists for live loads attic joists that are made from 2x8s may be acceptable for building your attic floor but because every room is variable there are no absolutes.
Irc attic dead load.
The tabulated rafter spans assume that ceiling joists are located at the bottom of the attic space or that some other method of resisting the outward push of the rafters on the bearing walls.
The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process.
The material and component weights tables 1 3 and 1 4 may help builders correctly size.
12 20 04 r301 4 live load.
International residential code chapter 3 building planning table r301 4 irc interpretation no.
Top of required insulation bottom chord of truss designed for live load 20 psf and dead load 10 psf bottom chord of truss designed for live load 10 psf.
Wide by 42 in high rectangle within plane of truss for two or more adjacent trusses top of required insulation roof trusses 24 in.
Attic access hatch minimum 24 in.
11 04 2000 edition issued.
Dead loads are defined by the code as follows.
The load combinations in table 3 1 are recommended for use with design specifications based on allowable stress design asd and load and resistance factor design lrfd.
International code council 42 in.
The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.
Dead load 5 psf.
International residential code 2015 irc 2015.
Calculating dead loads the prescriptive tables of the irc detailing continu ous footing sizes for conventional frame construction assume average weights of construction materials.
The weight of the materials of construction incorporated into the building including but not limited to walls floors roofs ceilings stairways built in partitions finishes cladding and other similarly incorporated architectural and structural items and fixed service equipment.
Maximum ceiling joist spans.
Load combinations provide the basic set of building load conditions that should be considered by the designer.