Ceiling Joist Size And Spacing For Attic Storage

Fine homebuilding notes that 2 inch by 6 inch garage joists will support a weight of up to 50 pounds per square foot.

Ceiling joist size and spacing for attic storage.

This ceiling joist span table is based on the 2012 irc for uninhabitable attics with limited storage. 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. 2 x 12 s are not listed because you can span pretty much whatever you want. 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.

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. Span exceeds 26 feet in length. 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. Building code trainer 2020 therefore if you have an attic space according to this scenario the ceiling joists can be designed for a live load of 10 pounds per square foot psf by using table r802 4 1.

The previous homeowner may have simply covered the joists with plywood to use the space for 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. In attics built purely for storage purposes you may find 2x6 ceiling joists or in some cases even 2x4 joists. Variations in ceiling construction nonparallel ceiling joist designs require additional support construction in the ceiling.

Uninhabitable attics without storage are those where the clear height between joists and rafters is less than 42 inches. 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. Although 2 x 4 s are included in the official table they are not listed because it is never advised to use them.

It covers 2 common lumber species and sizes at 20 pounds per square foot load. The dimensions of the joist depend on the span as well as the load it s intended to bear.