I received the same information that the other genteman provided, so we were in the same boat. My garage floor was all craked and broken up, both garage door openings were out of square and the roof was just starting to deteriorate, in fact one area even rotted away. However, I salvaged the whole 2 car garage by rehanging new garage doors, reshingling the whole roof, reframing the openings, adding new and extra supports, and tuck pointed the cracks in the floor. That was at least 90% less costly than replacing all the concrete, and building a new garage. You may even go a step further by having asphalt laid down on top of the newly tuck pointed floor. If you go that route, make sure you add some preventative measures so this won't happen again by adding or replacing the gutters around the garage. Also, before you re-do anything, see if you can get a quote on having your garage jacked up off of the floor and having them refit it on the newly square and repaired construction. I didn't have to go that far, even though the garage isn't completely square, I can live without the extra five thousand on my creditcard.