Floor Joist Dimensional Lumber

Span calculator for wood joists and rafters also available for the android os.

Floor joist dimensional lumber.

Dimensional lumber is cut to a specific length width and depth. 1 psf lb f ft 2 47 88 n m 2. 1 ft 0 3048 m. Key engineered wood terms prefabricated wood i joists.

When engineered lumber first appeared on my radar it was in the form of i joists to solve the crowning problems 2x10 and 2x12 joists created. Keep in mind the span table above shows just the allowable spans for douglas fir or larch there are different tables for all the construction lumber species. Dimensional joists are must be 2 x the width 16 max required to span. 2 grade of douglas fir are indicated below.

By also eliminating the use of heavy steel plates this light open web joist can speed installation time eliminate potential squeaking and reduce labor. The tables below provide both the nominal and actual sizes so many common north american lumber sizes. Dead load weight of structure and fixed loads 10 lbs ft 2. The narrow double lines show the floor joist themselves.

Joists are laid out from outside of framing to center line of joist in increments that center on 96. Maximum floor joist span for no. Live load is weight of furniture wind snow and more. Roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber spacing dimensions load and slope.

Triforce provides from 11 7 8 up to 16 depth from 6 to 30 long for less material than dimensional lumber. Switching from dimensional joists to i joists meant every floor was dead flat. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. Nominal 2 nets at 1 wide.

However there is a difference between the nominal size what the lumber is referred to and the actual size. I joists are typically available in long lengths and because they re very lightweight. Prefabricated wood i joists are structural load carrying products. From a three dimensional perspective the floor joist framing would look like this.

Dimensional lumber is also limited to smaller depths and lengths since its size is dependent on the size of the timber cut to make them. Then i transitioned to thick engineered advantech decking and that helped a great deal too.