Quarry Dweller

Introducing the Crypts Base down in the Parisian Catacombs. Lets all just pretend the shaded and white areas are the tunnels I was too lazy to draw.

For a bit of information. Essentially their base is a bunch of larger tunnels and openings blocked off with rocks and timber to create rooms and areas. The only way to get in is through one of those big green iron gates that they have positioned in the tunnel at the front. Its heavily padlocked, and cataphiles usually out of respect stay away from the area in general.

They do get electricity from a big power generator that has a big battery that needs replacing every fortnight, so the tunnels have lots of little wires and leads running into different areas of the base like the kitchen area and the medbay. So they can power things like refrigerators and microwaves.

Unfortunately they don't get plumbing, so if they needed to take a shit they would have to climb all the way out of the catacombs and find a tree. They usually shower at Pratik's Deli. They do have those portable fresh water dispensers that you can buy at the supermarket, and a washbowl for dirty plates and cutlery.

They tend to use alot of candles and oil lamps (though they prefer not too because it can be dangerous) for lighting in their rooms, and battery powered fairy lights for aesthetics!

The air quality is very poor down there to so they tend to sleep with those breathing machines for some peace of mind!

Even if there are some rooms that are made straight in the galleries, or have multiple entrances and exits, there are also quite a bit of them that have a single entrance branching out of a gallery. Here is a map snipped of two rooms branching out if rue de la Quintinie.

If your home is in a big intersection as your plan show, cataphiles will definitely pass through it to go where they want to go. Blocking multiple accesses like that would be considered very disrespectful. If your home is in a dead-end, you might have more privacy.

Timber isn't used down there to as wood rots very fast in a place with constant 100 % humidity, but stone is very often used to make furniture, with occasionally some concrete or metal used as well.

Battery connected to a power inverter as you suggest is the most common way to get electricity down there. Refurbished e-bike batteries are the most commonly seen.

Iron gates in a tunnel or at a room entrance is not unheard of. There are also rooms that are blocked off with rocks that people take down when they want to get in and then put back up when they leave. There is also somewhere a secret room whose door looks like the end of a tunnel, but it opens to reveal the room. But this might be a bit too wacky for your story.