We're remodeling our old 1950's garage into a Rec Room. The garage has concrete blocks (6" inches thick) with open ceiling. The garage measures 22'W x 25"L. There are some current "joists" of 2x8's spliced together running the 22' tieing the walls/rafters together. These are random about six at about 3' apart. The previous owners made a quick makeshift room on one side of the garage with the wall down the middle and a drop ceiling while the other side was used for a car.
We plan on gutting the whole thing and have it all used for a Rec Room with a large 8x10 closet on one end. My main concern is the current ceiling height. The garage walls are not that high and vary. On the far end it's 92"-93" for floor the top of wall. At the front is 87"-88". For the outer walls I plan on just building a new frames. The floor so far looks pretty good and leveled better than the walls.
I plan on making a beam that will span about 18' splitting the 25' into. That way I can have the ceiling joists go front-to-back riding ontop of the ledge plate. The length of the ceiling joists is abut 12' on one side and 13' on the other. I'll use joist hangers for a flush look. The beam will lay on top of a wall on each end and have one large wood post at the 12'/6'mark. Since we're not planning on any storage or use of the area above and a sheetrock ceiling I'm hoping to use 2x6's though I'll probably end up with 2x8's.
I just don't know how big of beam to make/use or should I think of two beams to lessen the load on one? I was thinking of (3) 2x12's with 7/16" OSB in between. I'm also concerned about one post being used. I was planning on (3) 2x8's with OSB in between. Sorry for the long post but I just wanted to get the details out. Thanks for your time and help.
Too much span for 2x6's. And at 13', just about to the end of a 2x8. You will need to put a footing under the post(s). You can't just have them set on the slab. I'd go with a concrete filled metal support over wood. For the main beam, I'd use 2x12 lvl's bolted together with a 1/4" steel flitch plate in the middle with only one support pole.