Our garage is a 12' x 18' shed, built probably in the 1920's. When we bought our house, it had a dirt floor, no foundation, some serious framing deficiencies, no human-sized entry door, and failing siding on the south and west sides that get all the weather. A layer of gravel, an access door into the yard, and an automatic opener for the flip-open garage door made it barely usable, and we've been parking our car and storing crap in it for a long time.
I've been talking about doing "something" about it for years, and I'm finally getting to it. Not that I've been ignoring the situation. I've drawn up various plans, and made two or three trips down to the city's permit office to explore the possibilities. Building a new garage is OUT. After all the setbacks are taken into account, it could only go into a fairly small defined area, near the back corner of the yard, and what am I going to do with the 5' setback area around it? Pretty tough to make use of those little strips. Then there's the cost. Permits, demo and disposal of the old garage, and all new materials for a new garage will probably wind up costing me at least $10k, and that's complicated by the fact that we're in a flood plain area, so I'd wind up paying for an elevation survey and wind up building the lower three or four feet of the structure from all pressure-treated wood or concrete block. $...$...$...
The one really nice thing about our old garage is that it's totally nonconforming from a zoning perspective. It's about 2' from the back lot line, and a little less from the side lot line where the driveway is. Those setbacks are supposed to be 5' and 13' respectively. The downside is that the only entry ramp onto the property runs right into the garage, so I have to pull trailers, extra cars, etc. up over the curb and into the yard via a gate next to the garage. That sucks. Early inquiries with the city into getting a permit for another curb cut and driveway apron were the usual expensive pain in the ass.
The solution: I'm going to have my own covered bridge. Well, sort of. I'm going to install a second garage door on the back wall of the garage, so I can pull through it into the back yard. The main issue to think about is the shear strength of the structure, once there are two 7'h x 8'w doors cut into it's 12' wide end walls. The current framing configuration definitely wouldn't survive, and in fact I'm kind of surprised the thing is still as square and plumb as it is, but some proper braced panels, bolted down to a decent concrete foundation should do the trick just fine.