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
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".