Need more garage space and work space too

[JWT55]

Hello, This is my first post. I began looking for garage blogs because I have a 2 car garage that is 21.5 ft by 28ft without a center girder. There is a 16 ft garage door. The garage is attached to the house on the first and second floors but the 2nd floor is odd. There is a gable facing front and back so the 2nd floor garage attic is only 12 ft wide by 28 ft long with a narrow hall about 5 ft wide connecting it to the house. I would like to make an addition to add about 10 ft to each side of the garage to add more garage space and to add additional space to the rooms on the first and second floor on both sides of the garage. I would like to make the hall connecting the garage and house into about 35 ft from front to back connected all along one wall of the garage and extending further back to add additional workshop and 2nd floor storage space and a billiard and family room above the whole 3 car garage.
My first question is if it would be feasible to span the 21.5 distance between load bearing walls with a floor that could support a slate pool table using dimensional lumber or would I need I joists? Or do I need to put a girder in the middle of the span?

 

[scarpozzi]

I just built a 30' x 30' attached garage with an upstairs. I used 16" I-Joists on 12" centers. It turns out that over the 30' span, the center of the I-Joists dip about 5/8" in the center of the room. There is a bounce to the floor....it's not too bad, but should tighten up a little after I put sheetrock downstairs on the ceiling of the garage and put down hardwood upstairs.

So for my upstairs, I used 33 I-Joists. FWIW, I ordered them from Home Depot and paid about $2600 for all of them. I dropped another $300-400 on a rim-board....basically it's a 16" x 1" thick piece of OSB....very heavy, but it really steadied the beams and fit perfectly like a puzzle.


If I were going to put a slate pool table up there, with the expectations of having more than a few people in the room, I'd likely go with a steel H beam to get rid of the bounce. You can get steel in precut lengths. When I looked into steel for my build, the cost of a 30' beam was pretty expensive because I would have had to buy a 40' beam and have it cut to length. If that's not a possibility, go for the wood I-Joists. They're very cheap/light/strong....just expect some bounce over that span and make sure your walls are sound.

 

[Vegaman_Dan]

Post a couple of pictures of the home/garage from a couple of angles, maybe one inside the garage looking at the structure. That will help greatly with the responses you get.