Re: How to begin renovating a poured cement garage
Those old concrete garages are pretty cool. They were built because they were fireproof and were usually detached form the home. Since only and idiot would store a gasoline powered horseless carriage in a building attached to the home.
My neighbour has the same type of garage. The roof is used as a patio and overlooks the river. His had a passage below ground to access the house.
I agree, you have to fix the leaks in the roof first, then work on the garage door so it's functional, then upgrade the electrical. Outdated electrical tends to get more attention that needed. People usually only have problems with old wiring when they overload it, or it's poorly installed or been modified. New wiring can be equally or more dangerous if not installed correctly.
Just a good quality caulk might seal those cracks. Or you might consider coating the concrete roof with an epoxy floor coating material. Those have some flexibility and may prevent hairline cracks from causing leaks in the future.
1925 Two-Story Stucco Beaux Arts Neoclassical