I live in AACO and did this 3x last year and back in 03. If you are zoned R-A RLD or R-1 then you are correct principal structure does not matter anything else and it is capped at principal structure.
What are you zoned? Did you talk to the planning a zoning office or just the permit office...
I just finished my 24x26 garage in annapolis and I can give you a few tips. If you want more room inside go with a higher pitch and canterleave the over hang that will raise the peak of the roof for more room.
I went with a 12/12 with a 1" over hang on both sides...
I am not aware of any difference. I think HD was moving from CertainTeed to OC with siding and insulation so they may push that now. I have used CertainTeed siding and insulation and never had any problems. If you want to check for better prices call ABC supply they are in Landover I believe...
If you are looking at Home Depot they have $100 off every $300 till 6/27 on insulation and you may want to stay away from MT RD Home Depot it can be a mad house.
Chris
Those are not the doors I am going with I am using this.
http://www.clopaydoor.com/gallerysteel.aspx
I wanted to put in an overhang in the rear but did not have time and the scissor lift I had could not be used back there. I finished the deck and got my framing inspection so now I am installing...
Code limits to 25' and we have it set at 23'5" now with 9'8" down stairs. We are adding a second floor to the house next year to match the garage that is why we went with 50yr shingles and cedar perfection siding.
I had them canterleave the truss so I could move the knee wall up to 6' instead...
I have been looking around here for a while and this site has been great for getting ideals. I am about 80% finished with just siding, hanging the doors and some grading left to do.
The garage is 24x26 with a 12/12 pitch roof so it has a 12x26 room upstairs. I did all the work minus concrete...