Span Tables Lumber Professional-Level information and how-to-build articles for wood, timber, and lumber professionals and users. Span Tables » Lumber Talk
By Chris | December 7, 2007 - 8:50 am - Posted in Alternative Materials, Plans, Specs & Data, Structural Components

Construction Span Tables

I often get asked by engineers, architects, and designers (and farmers) about the span tables for dimensional lumber. So, I have compiled a list of many places with various span tables for your reading enjoyment and project fulfillment. The idea here is to create a one-stop shop for span tables so let me know if I am missing something.

Roof Truss Span Tables: This is a great find for roof truss span tables. It is easy to use and breaks down the span tables by truss type, pitch, and length. Here’s a list of roof truss manufacturers, too.

Maximum Span Tables for Joists & Rafters: The MSR Lumber Producers Council created and published these span tables floor joists, ceiling joists, and roof rafters. The pdf is 12 pages long and the span tables start on page 3.

Span Tables for Structural-Use Panels: Free pdf download from the APA Engineered Wood Association for Structural-Use Panel Span Tables.

Floor Joist Span Tables: probably has the best publications – like this one showing floor joist span tables.

Residential Steel Beam & Column Span Tables: This is a pretty specific span table (warning: 29 page pdf) developed by the American Iron & Steel Institute. The span tables start appearing on page 12. If you are having trouble sleeping, start at the beginning. Otherwise, stick to the span tables.

Lumber Span Tables: This is a span table for U.S. Spans for Canadian Species from the Strober Organization, Inc. a supplier for contractors in the eastern U.S.

Header and Beam Span Tables: These span tables are a great find if you are trying to build with beams and/or engineered lumber. The pdf is free from The Southern Pine Council.

Deck Joist Span Tables: Their is a good span table tool in here for deck joists but I cannot link directly to it so go here and click on “Joist Calculator” about halfway down the page. You might have to sign up/in.

Span Table Pocket Card: This is like a cheat sheet from The Souther Pine Council. Every wood professional should have a copy of this around somewhere. The pdf is free or you can order the real thing (laminated) for $0.50 each.

Beam Span Tables: The American Institute of Timber Construction has a nice list of tools and span tables for timber construction.

Bridge Span Tables: This is just interesting and offers no actual value. It is a chart of the longest bridge spans around the world. By “span” they are referring to the distance between the two farthest-apart supports on the bridge (the longest spans). The lengths, which are in meters, are not referring to the total lengths of the bridges.

Tell me what I missed. I know there are a million other span tables out there and I would like to list them here. If you know of something, add it yourself as a comment and I will add it to the list.


  1. June 5, 2010 @ 8:33 am

    Looking to remove beans from a 12.5 foot span. Currently their are two 4x4s approximately 4.5 ft apart. The wall is on an outside wall of house on first floor of a two story building. Looking to remove 4x$s to open space and replace header with microlam beam. Asing if there are any suggestions for the size of beam. Would like to keep it to 3 1’2 in width if possible.

    Thanks for any assistance.


    Posted by Mike
  2. July 14, 2010 @ 4:01 am

    I’m not touching that one with any size pole – way too many variables. You need to ask a local designer or contractor.

    Thanks for writing – sorry for the useless response but, well, it’s 2010 in litigious America. 🙂

    Posted by Chris
  3. April 16, 2011 @ 11:05 am

    I purchase a 1961 house 3 years ago. The kitchen has 2×8 floor joists, 16″ on center, which span 14′. Unfortunately one of the kitchen walls was set 4′ in from the span support (nothing underneath). This wall had the refrigerator and stove and cabinets even further in from the span support. (The wall has since been moved.) The floor has sagged as much as 3/4″. What would be the best way to correct the sag and stiffen the floor?

    Posted by Tom
  4. May 13, 2011 @ 4:48 pm

    As you may be realizing now I steer waaaay clear of residential span questions. You should look for span tables 🙂 and consult (in person, at your home) a designer or building pro.

    Posted by Chris
  5. October 2, 2011 @ 10:49 pm

    I have an 1906 home in the SF that the Kitchen floor has an 3/4 ” dip in 11 ft. The floor is old school 2×8 16 on center, the beam supporting the joist is an 6×6 and has a sag of 1″ in 16ft the wall above the beam carries a ceiling and a tar and gravel roof I need to know what size beam should I use to sister next to the 6×6 and should I cut or pull all nails holding down the floor joist or should I leave and try and straighten the old 6×6 also

    Posted by Bob
  6. October 17, 2012 @ 10:29 pm

    It is well known that I don’t touch questions like this. My suggestion will always be to ask a local professional contractor, engineer, or other construction professional. Also, how did I not see this post for so long? Sorry about that and thanks for posting.

    Posted by Chris

Leave a Comment

Please note: Comment moderation is enabled and may delay your comment. There is no need to resubmit your comment.