I'm building a shop beside the house. The roof will be galvalum with a 1/12 pitch. The building will be 30' x 40'. For 3 of the beams I'd like to skip a post and span 25'. Live in Alabama, so there's no real snow weight risk. I'd prefer to cut a beam, or sandwich with plywood two beams, but am wondering if this is practical. How much less expensive is glulam over iron? What dimension beam would be necessary here? Oh yeah, the posts I'm using will set on a concrete base. 2x6 rafters every 24". Planning 6x6 posts, but I have some 12" dia telephone poles I've thought of using.

Any help would be appreciated.