Decks, Patios, Porches and Docks - Age old questions... Beams and Spans...

I've not had much luck with research on the web with regards to span tables. So I apologize for rehashing this subject (and I do intend to check local building codes).

Here's my situation.

My location is Georgia. I'm attaching a deck that will be 25 feet wide on the edge that is attached to the house. The deck will be approximately 10 feet above ground level. I've already poured pylons for the support posts for the beam. They are @30 inches deep, tapered to prevent frost lift and the top of the pylons extend 6 inches above grade and have "J" bolts to hold the brackets for the support posts. There are 5 of these pylons and they are 71 inches apart and they are 11 feet from the house.

The support posts will be 6X6 pressure treated pine.

My original plan was to create a 25 foot beam out of 2X12s (pressure treated pine) to make a 6" X 12" X 25' hunk of wood. The joist system was to be 12 foot 2 X 10 on 16 inch center. So it would be cantileevered 12 inches over the beam.

I would like to get a little more width out of the deck. Does it seem sound to make the following changes? Create the 25 foot beam with 10" boards instead of 12"? So it would still be 6" wide, but only 10" high... still on 71" posts. I would like to switch the joist system to 2" X 12" X 13.5' and on 16" center. Basically I'm swapping some of the beam material around with the joist material.

That extra foot and a half would give me an extra 35 feet of deck space.

Thanks in advance.

NTAC

NTAC:

Is there a reason you can't use 2x12s for both the beam and joists? It would lower your beam by 2 inches.

apiersma

No... but I have some 2X10 material that will go to waste if I don't find a way to use it.

I would still have 8 feet of clearance under the beam.