Attic Joist Span Tables

As mentioned above the span tables within the code list the allowable ceiling joist spans for common lumber sizes based on what design load scenario is applied.

Attic joist span tables. Table r802 4 1 ceiling joist spans for common lumber species uninhabitable attics without storage live load 10 psf l δ 240. Attic truss span table october 28 2017 by zamira leave a comment 30 diffe types of roof trusses roof truss endix 1 8 13 span tables city of garage attic ion the 30 diffe types of roof trusses. Joist span tables. 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.

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. Lumber design values use of these span tables requires reference to the applicable design values for the various species and grades of lumber. Builders generally use pre calculated tables to tell them appropriate joist spans for each lumber species size. Spans for ceiling joists shall be in accordance with tables r802 4 1 and r802 4 2.

Straight line interpolation shall be permitted for intermediate spans and design values. Joist span tables use these tables to determine lengths sizes and spacing of ceiling joists. Joist span table use these tables to determine floor joist spans based on grade of lumber size of joist floor joist spacing and a live load of 30 lbs ft 2 or 40 lbs ft 2 these tables can also be used to determine deck joist span. How to reinforce an attic floor with sister joists.

Ceiling joists of the first floor of a two story structure often serve as floor joists for the second floor. An inaccessible attic space on the other hand might have a live load of only 20 psf. If this is the case with your structure use the floor joist table to determine maximum joist length load. Also remove any blocking or bridging between the joists as applicable.

Pull out all insulation and any debris from all of the joist spaces so you can see the full length of each joist including where it meets the exterior walls. Clear the joist spaces. Joist span refers to the measurement covered by the joist between supporting structures such as beams or foundation walls. For uninhabitable attics without storage we will use table r802 4 1 and for uninhabitable attic with limited storage we will use table r802 4 2.

Ceiling joist span tables. For other grades and species and for other loading conditions refer to the awc stjr.