Rafter and joist span faq.
Floor joists for 13 foot span.
For two equal spans the listed span is the center to center distance from either end to the center support.
2 grade of douglas fir are indicated below.
Calculated allowable properties are based upon aisi s100 07 north american specification for the design of cold formed steel structural members.
Floor joist span tables for various sizes and species of wood.
Common sense tells you that large floor joists can carry more load and spacing joists closer together also increases the load bearing capacity of a floor.
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.
The lengths and sizes of joists vary depending on the species and quality of the lumber used.
The table below shows the maximum span for a floor joist with the following designations.
The extra two inches of vertical distance when a floor is framed with 2 x 10 joists rather than 2 x 12s can be quite important for example.
Span calculator for wood joists and rafters also available for the android os.
Table notes spans are based upon continuous support of compression flange over the full length of the joist.
The illustrations one for cantilever joists and one for flush rim beam hung joists point out where joist span measurements are taken from the saddle of the ledger mounted joist hanger to the center of a dropped beam or saddle of the.
For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine.
Douglas fir larch lumber species no.
So we now have adequately sized floor joists and an adequately sized floor joist beam for our 24 x 13 house.
Span entries are listed for 2 6 through 2 12 joists and 12 in 16 in and 24 in.
Our joist span charts are for wood joists with a maximum dead load of 10 pounds per square foot and a live load of 40 pounds per square foot.
This chart is for basic reference only.
Our floor joist beam can span a maximum of 13.
Also available for the android os.
Maximum floor joist span for no.
Let s start with a simple very small house 12 feet wide by 13 feet long.
The house will have a gable roof and will be framed with wood studs.
Live load represents the weight of furniture snow etc.
1 psf lb f ft 2 47 88 n m 2.
2 lumber grade all joists are bridged sample floor joist span.
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.
Dead load is the weight of the structure and any fixed items.
If you have any questions.
But larger is not always better when builders are constructing a home or adding a room addition.