Building departments, like people, have personalities: some are a lot easier to deal with than others. Some jurisdictions exercise their charter more zealously than the one next door. Some are efficiently run, some lose paperwork, or need need constant follow up to move things along. Fortunately, in my experience AHJs on the whole have become much more professional, efficient and honest over the last 40 years.
Assuming yours is an average building department, what I'd aim for more than anything else is a non-adversarial relationship.
There is a good chance you are going find there that there are seemingly arcane rules and regulations which cost you and time and money, which don't seem to make sense, are confusing, appear to be applied retroactively, or are actually in conflict with something you were told previously by someone else in the same department, or by some other department.
Expect these sorts of difficulties.
On my projects - I do some development in a small way - the building department's inspection of work done by careful and experienced tradesman usually turns up a few thing that need to be changed. And you can expect the same - only more so - of work you do yourself.
Remember - always - that to a large extent these guys (and the occasional gal) get to make the rules, and getting into a argument with a zoning analyst or a building inspector (who is probably wishing you had hired someone who already knows the rules) is almost always a losing proposition.
That said, your's is the right approach - go down to the building department, find out what is expected of you during the portion of the work you will be doing, and make sure that you understand - form the City's point fo view - the division of responsibility between yourself and others working on the property .
Ask about general regulations governing the sort of work you will be doing - for ecample during demolition their may be prohibitions on noisy work evenings and/or weekends, regulations on dumpster placement and the length of time they can sit, environment regulations and/or fees fees regarding the disposal of demolition debris, requirement to fence off the property before you start work, and so on.
Establish if there are permits required for your portions of the work, if the require inspections, and if so how you request inspections, the lead time required, and so on. (Are there (re)inspection fees? Are they in your budget?)
If you will be doing permitted work, ask if the building department publishes a "checklist" or "guide" listing the problems they most frequently encounter during inspection of these systems, or any other sorts of material useful to a homeowner in your position.
And if possible, try to get a feeling for any sort of anticipated work the build department does NOT want you doing yourself.
For example in my community a homeowner can pull a permit to do almost any sort of work on their own house, and when when rehabbed I applied for a permits to do a *lot* of plumbing and electrical.
Permits granted, no problem.
I also applied for a permit to replace the water line out to the street.
Somehow, that the permit did not get issued, calls didn't get returned, etc.
Eventually, I wised up and asked the plumbing inspector why.
"Well, the City really does not want homeowners touching anything their side of the meter.
"You know you are able to do it right. I know you are able to do it right.
"But the Water Department does not want *any* homeowner doing it, and it will take FOREVER to get that permit."
That's exactly the sort of battle you don't want to fight, and ideally you want to develop the sort of relationship with the building department were they regard you as a competent, honest and reasonable (if perhaps somewhat "over-ambitions") homeowner, and are they are willing to be candid about such "facts of life".
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Finally, though this isn't "Building Department" advice, if you haven't already done so pick up the phone, contact your insurance agent, and find out what you have to do to completely protect yourself during this project. For example I've been consistently advised (by attorneys as well as insrance agents) that in my state it's wise for a homeowner undertaking major work to to carry their own workers'-comp policy as a backup again the possibility of responsibility for the injury or death of an employee of a contractor or sub who is not properly insured. For example thay have a certificater of insurance, but missed ths last three payments).
Good luck with your project,
Michael Thomas Paragon Home Inspection, LLC mdtATparagoninspctionDOTcom
847-475-5668
847-475-5668