Advice for mapping buildings?

[Togath]

Does anyone have advice on resources to draw from when trying to map out a complex building? Small houses or businesses are relatively easy for me usually, but when I get up to manors or government buildings(not, like, castles. More like buildings where city officials might do business) I start to struggle more. Like, for what size rooms should be, how many rooms of various types it should have, etc.

Period-wise for design I think somewhere in the vague 1500s-1800s range.

[Yora]

What I consider the most practical approach is to not draw the entire building, but only those parts of the buildings that are likely to be of any interest to the players. With rooms that are pretty much repeating many times, its's enough to have only one or two drawn.

[Imbalance]

Municipal buildings can be ornate in structure while mundane in layout. Stick with a grand entryway, overly spacious, with large rooms in a four-square arrangement off of that, and very small rooms in the gaps. Wide stairs go up, a narrow stair leads to the basement.
The second floor is cramped offices. If your grand entry is an atrium or rotunda, the only sizeable rooms upstairs are adjacent to that vertical space.
A ladder reaches the stuffy attic, full of some of the weirdest, most out-of-place and unexpected junk you can imagine. There is almost always a small hidden room somewhere up here, or access to a hidden catwalk in the rotunda or a bell tower, a place with a clandestine viewpoint.
The basement is the least typical space, by and large. There could be cafeterias, libraries, holding cells, offices of all shapes and sizes, chapels, morgues, barracks, stables, a single large room with gothic columns, or endless winding corridors, everything in between and all of the above down there, with a single small street access door in the location of the least possible convenience to the public.
If your setting has plumbing, this building did not begin its life with it, and there will be exposed pipes in corners above ground and seemingly everywhere below. Place large fireplaces liberally, and try to stack the chimneys from floor to floor. Big windows, high ceilings, thick exterior walls, sparse ventilation, copious clutter in neat, out-of-the-way stacks.
A larger building is comprised of wings added to the main house that mimic the layout with a less fancy motif and likely has better disguised utilities because they were built much later. A taller building has more diversity on the uppermost levels.