I have and existing deck about ten feet off the ground. The joists are all doubled up 2x6 S. Pine 11' 7" in length. There is a double 2 x 10 beam running across the middle. I need to remove this beam. I need to install some corrugated roofing to create a dry space but I can't do it with the beam in the way. I have seen several tables that say 2x6 can be used but only for a 9 foot span. My joists are all double runs of 2x6's. Can I get rid of the beam? Thanks, Mike

  • I sincerely doubt that your beam was just thrown in as an optional extra. It would help if you could draw a rough sketch of the structure (viewed from above, indicating posts, beams, joists, rough dimensions). Add an imgur-type link to it and someone here could help you integrate it with your post. (New users can't post pics right away.) – Aloysius Defenestrate Mar 19 '18 at 13:47
  • Hello, and welcome to Stack Exchange. Questions like this often are best addressed by a structural engineer rather than by us, but as @AloysiusDefenestrate said, more info would help us. – Daniel Griscom Mar 19 '18 at 13:48
  • The beam is supporting your joists, how do you intend to support the joists if you take away the beam? Your question is confusing, do you want to add more joists or do you want to remove the beam that is supporting your existing joists and replace it with something smaller, what will your existing joists sit on? – Alaska Man Mar 19 '18 at 15:49
  • The inference is that there's a second beam at the outer ends of the joists. I assumed we weren't talking about a 5 foot cantilever. :) – isherwood Mar 19 '18 at 17:06
  • Can you put the beam back when you're done installing your corrugated roofing? It will likely be fine temporarily, just keep weight off the deck while you're at it. – paul Mar 19 '18 at 22:36

Doubled 2x6 joists are probably strong enough, but they're not going to be rigid enough to prevent significant bounce. That's why joists spanning 12 feet are usually 2x10 or 2x12. You need to upgrade your joists and possibly the single remaining beam to eliminate the intermediate beam.

Alternatively, consider cutting the intermediate beam into the joists to be flush on top, and add joist hangers. This would raise it by 5-1/2".

  • An alternative to 2x10 joists would be a flitch plate bolted to the joist. Just fitting bigger joists would probably be easier though. – Martin Bonner supports Monica Mar 19 '18 at 16:27
  • I don't mind a little bounce. The deck is only used occasionally and never more than 2-4 people (and a couple of dogs) at a time. Thanks for you help. I like the idea of cutting the beam into the joists and using joist hangers. This is a great idea. – M. Morton Mar 20 '18 at 15:01
  • You're welcome. Take the tour if you're not familiar with our voting mechanism. – isherwood Mar 20 '18 at 15:51

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