Ceiling Joist Size And Spacing For Attic Storage

Although you can construct a garage using thicker stronger joists 2 inch by 6 inch joists are sufficient for most garages even if you intend to build an attic storage area above your garage.

Ceiling joist size and spacing for attic storage.

Although 2 x 4 s are included in the official table they are not listed because it is never advised to use them. Fine homebuilding notes that 2 inch by 6 inch garage joists will support a weight of up to 50 pounds per square foot. From the table the minimum is 50x97mm which is approximately 2x4 in but it doesn t give any indication of the load that that will bear. 2x4 s actual size spaced 16 on center running the width of the building uninterrupted with the ends resting on top of the wall top plate.

Joist spacing of 24 inches is allowed for spans between 16 to 20 feet using 2 inch by 10 inch lumber of these three grades. 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. 2 x 12 s are not listed because you can span pretty much whatever you want. 1 inch 25 4 mm 1 foot 304 8 mm 1 pound per square foot 0 0479kpa.

In attics built purely for storage purposes you may find 2x6 ceiling joists or in some cases even 2x4 joists. I d like to double my ceiling joists to make my attic space easier to work in for electrical plumbing and for lightweight storage. Ceiling joist spans for common lumber species uninhabitable attics with limited storage live load 20 psf l δ 240 check sources for availability of lumber in lengths greater than 20 feet. Span exceeds 26 feet in length.

The dimensions of the joist depend on the span as well as the load it s intended to bear. It covers 2 common lumber species and sizes at 20 pounds per square foot load. For example the highlighted cell below shows that a 2 x 6 southern yellow pine joist with a grade of 2 and spaced 24 apart can have a maximum span of 10 feet 0 inches 10 0 if you are designing your structure to support a plaster ceiling. This ceiling joist span table is based on the 2012 irc for uninhabitable attics with limited storage.

The previous homeowner may have simply covered the joists with plywood to use the space for storage. While this is not the optimal setup it is acceptable to have ceiling joists covered with plywood or osb to use for light attic storage of dead loads.