Actually we just did a detached garage for a new house customer that has a span of 26 ft and we incorporated the loft type area above right in the trusses so there was no beam at all. We used an 8/12 slope. It depends on your situation. If it's attached it makes it a little more difficult but give me a few more details and I can help you out with it.
Also what kind of wood are the 2x12's fir, spruce and I would guess they're 14 ft long? Also what stage of construction are you at? Thanks, Mark
2x12’s = Top Choice #2 Southern Yellow Pine 12’ Long
I have the foundation complete, getting ready to install floor joists
Hi Dave, It's not possible to do it with a built-up beam maximum span for 5-2x12 is 12'-9". You can do it with a glue-lam. The size you'd need to do a clear span is 5-1/8" thick x 15" deep. Now to save on headroom you could send the beam up into the floor space and use hangers to attach the joists to the side of the beam. This works well we've done that a lot. You could also do it with a steel beam which is probably somewhat less expensive than a glue-lam. Size W10 x 22 which is about 6" wide and 10" deep. These figures are taken from my building code span tables which are more than adequate.