Nevada Mike wrote:
...I decided to add it to the end of the old attached 2-car garage, ... I did a lot of the work, electrical, insulation, plumbing, and helped with the framing. Even learned from my mason how to lay brick. Spent many hours up on a double scaffold with the wiring, insulation, taping drywall, texturing, painting, etc. Total cost $35K (in 1998 dollars), not including my labor, and that of a lot of friends.
Still standing after 20 years, and I've spent a lot of happy, productive hours out there. It will cost more than you expected. But every dollar is well spent, and will seem insignificant in a couple of years. Put in lots of lighting, and you can never have enough 20A outlets. Even put in 220, and a 200A breaker box. And heat, you gotta have heat...
I completely, completely agree.
I finished my garage expansion earlier this year where I pushed the back of my 2 car garage rearward to make it a 2 cars deep. One of the rear quarters is actually my shop; not for parking a 4th car. I have not added up all the bills because I want to be able to honestly tell my wife that I don't know how much it cost. I easily spent over $30k despite doing a huge amount of the labor myself although it included a full replacement of our 1978 furnace and A/C.
I agree on the electrical. Regarding HVAC, I did not ventilate the garage. Here doing so bumps the property tax category to more heavily taxed "conditioned living space."