Floor Joist And Cross Beam Design

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.

Floor joist and cross beam design.

In this video we discuss design and analysis procedures for joists beams and girders. Cross sectional area nominal adjusted wood education institute reference value. Floor beam span tables of residential structural design we will now look at roof rafter and beam design. Both the 2009 irc and the dca6 09 allow 2 southern pine 2x10s to span 13 feet 1 inch at 24 inches on center at a design load of 50 psf.

The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial. In the table above the widest floor beam span for 12 of supported floor joists is 14 7 if using a 5 ply 2 x 12. Though joists may be any size that you desire using typical floor joist and beam specifications ensures that you can find hardware to fit the joists and that the floor provides adequate support for furniture and other items in a room. W l 40 psf.

Floor joists or beams provide the below surface support for the wood subfloor of a room. Let s consider a basic gable wood roof framing design. Joists are the repeated structural members that are used to build a deck frame. Beam design example.

So we now have adequately sized floor joists and an adequately sized floor joist beam for our 24 x 13 house. The minimum size joist to be used in deck construction depends on the number of footings and beams that will be installed. True floor joist span calculations can only be made by a structural engineer or contractor. S 8 ft.

Nine joists will be needed for the 16 foot width. Pier and beam foundations offer a high level of versatility specific not only to the dead live seismic and wind loads to be supported and or restrained but also to the girders or sill beams and floor joists and their respective span capabilities. Wood member design asd or lrfd compares demand to capacity. Design of 3 3x12 beam with southern pine.

Joists 2x12 floor beam notched to 9 1 4 at bearing 3 2x12 floor beam post in wall under beam end bearing wall studs. Beam design example check notched 3 2x12 beam for shear. L 16 ft. A beam is the main load bearing element for the structural soundness of your deck s roof.

W d 10 psf. Superimposed dead load including mechanical and electric load w sd 8 psf. Here we have a wood framed gable roof. Our floor joist beam can span a maximum of 13.

That means these joists can span the 12 foot depth of the deck and the beam can be located at the perimeter. Continuing on from part 3.