I think that must be it. Somewhere in the back or on the sides, there must be exterior access.
Do you happen to know the address? You could try googling it, and take a look
at the roof view, and at the different street views.

You might be able to get a sense of where the stairs are by moving down the street just a bit,
or maybe you can see the rear of the building from the street behind.

The front door in the photo isn't the same as the door to the entrance hall in the floorplan. It looks like there's another hall, probably including some stairs, that's not shown in the floorplan.

It looks to me like that house has been subject to numerous changes, and what they ended up with might not be very practical. I've seen the same in apartments I have been renting both in Rome and London. Hopeless layout, I'm thinking it used to be much bigger, now they have devided it up, or perhaps they needed to fit an elevator.

That house looks to me like they had 1 family living there with perhaps a business on the ground floor. Now it's turned into one smaller family on each floor, and suddenly they have to fit all functions on each floor.

Did you plan on making it for more families, or do you want a one family accommodation?

I agree with arathea, I should think you'll find the true/original entrance hall and staircase in the blank space between the reception room and front bedroom as that ties up with the exterior, I'm guessing they omitted it from the floorplan you found because it's a public room used by all of the residents of that building. Usually when these grand Victorian villas are converted into flats, the main staircase is kept to add a sense of grandeur that is otherwise lost in the flats that are accessed from it. I could certainly suggest some comparable examples of how the actual entrance hall of that house may look.

Thanks everyone! I am going to play around with it. I didn't think the space between the reception room and front bedroom was large enough to be an entrance + staircase, but perhaps I can make it work. I was going to make the first floor an apartment and the top two would just be a shell. The game seems to have issues with more than one apartment, at least for me. Any suggestions?

Which game are you building in? If it's TS3, Volvenom is a pro when it comes to apartments, she should definitely know a thing or two that might be helpful.

attuned might have tried an already tried and tested house, that just wouldn't work in his/her game. It happens. I can help you out though, shouldn't be too much of a problem with that house, if you can find somewhere to fit the staircases.

I am building in TS3.

@Volvenom What is the advantage of making the building have three apartments, instead of one on the first floor, and the upper two floors empty? I want to give the illusion of a three story building, but it seems simpler to make just one apartment. I would love to know what you think. Thanks!

It's very simple to do. You just put hidden markers in the two upper apartments, in all the rooms. it's better really if you just ditch all decoration and have no room. You kan just put some walls in if you don't like it from the window. nitromon suggested having rooms by the windows, and just have the tenants in the middle or something. It doesn't matter where you put the NPC's really. The game doesn't really do anything good with them. If you have anything good in the apartment it will just add to the price for your active family.

The rooms and balconies you don't use for your active family, you can put public markers in.

The NPC's needs to have their own door, and making the structure too complicated will make your job more complicated and the game might not even understand. You can have a hallway with a staircase inside and have doors to each apartment from there.

If you don't make it too complicated, you can quite easily make yourself some nabours to play with. I'm not a player though, but you probably knows quite well already how an NPC works in game, much better than me.

If you put tenants in, they will help out paying the bills.

@attuned

Can I leave the upper floors empty, or are hidden markers necessary? Thanks for your answers!

I think the hidden markers has to do with pricing of the active families flat.

I am working on an Arts and Craft Cottage. If anyone has a chance, there is a new thread for it, in Creator Feedback

EDIT: uploaded to queue- thanks everyone!

Do you know that feeling, that great feeling, when a lot you are working on suddenly "works"? When the layout comes together, the roof looks good, the colors are complimenting each other well? Yeah, haven't had that feeling in a loooooong time for any of my builds. I keep tucking lots into my WIP folder and moving on. I guess it's a builder slump.

So I discovered a new technique. Well, perhaps it's only new to me. In TS3 when you are using the Move Objects On cheat, you can move or delete the different parts of the fireplace chimney. That's not the news. The top section, the chimney cap, will continue to issue smoke, even if the rest of the chimney is deleted and it's moved anywhere else. If, however, you decide to build your own chimney around it, smoke will come from the level of the cap, and not from the top of your chimney. I wonder if you can raise the cap with NRaas debug enabler so the smoke comes from the top? I have to try that next time I'm in game.

Yes I have tried making it fit as well. Does the debug enabler make stick there? I have seen with other solutions if the support isn't there anymore it can drop from it's place, whatever it is. Like windows without support falls.

Would they stay more in place with the debug enabler?

Debug enabler and Decorators Best Friend place the object in space, so don't require support. If someone doesn't have the mods in their game and they move the item, then it will fall to the floor. I am not sure if it will work with the chimney cap and smoke, but I'll try it out and report back.

EDIT: The chimney cap stays in place, but the smoke comes from an odd place- so not ideal.

Hey @attuned thanks for the compliments on my lot
I already have both Debug Enabler and DBF, the latter gets used often for moving objects around and I love it! The reason I used OMSPs in that lot was mainly to resize stuff, and since the Resizer OMSPs require the original OMSP to work I was like "eh, OMSPs are a bit more convenient to use than DBF so what the heck". Do they really cause lag though? I did notice that the camera movements while panning across that lot were a bit jerky, but thought it was to do with the amount of objects used. Perhaps not.

Oh and maybe this is already mentioned in the thread, but instead of having to remember the name of the object you want to move with DBF then painstakingly search through the list of objects for it, it's much easier to just select "add move interactions to all objects in room" while in Live Mode.