Our first house - your advice is needed!

Good morning everyone.
Many thanks for your comments!

- It is apparently a hillside property. The basement level is accessible at the top of the plan and even has 2 entrances! Of course, one immediately wonders about the access route. Do you have a picture of the entire property – if necessary, copy Google Maps and draw on it by hand? Maybe the entrance for the electric bikes could be relocated there.

You're right! Attached I uploaded the property via GMaps. It is the white house with the white parked car. There is a small path running along the short side up to the first terraces, then the path descends towards the basement. I hope that’s understandable. Such things are also difficult to implement, especially when tenants are living in the house; they would have to walk over my terrace every time to get to their apartment.

- Is the basement dry? Like completely dry, for living in? I suspect yes, because it says "child," but with existing buildings, you never know.

Well, the rooms that are inhabited are dry. The oldest of the children still lives there. The basement rooms also looked dry. As a layman, it is difficult for me to assess; a moisture meter for walls would certainly bring clarity!

- Regarding questions about insulation, you first need to know the current state. What kind of walls are those, how thick are they? Otherwise, I first see the windows and roof for energy savings. Probably nothing else is worthwhile.

Can’t the wall thickness be taken from the drawing? I seem to remember the word "aerated concrete" was mentioned for the walls as already mentioned by 11ant. I’m not sure!

- Which windows new – that’s a question of price. I recommend Polish windows – a real price hit. Here in Saxony, literally "close by." Very good quality for half the price. I would always only install plastic windows because of the painting effort, as long as it is not a listed building.

I talked to someone at work. He holds the opinion that too well-insulated windows in a house from this year of construction promote mold growth, how true is that statement? What kind of insulation would you suggest?
Also, it’s a matter of security; many windows are at ground level, so easily accessible. How well can one protect against break-ins there?

- 2 heating systems are nonsense – volume meter and that’s it. I wouldn’t force a new underfloor heating system – the cost for retrofitting is crazy. Better are modern radiators. With their structure, you can manage to heat at low temperatures. That way, you can also integrate the existing underfloor heating. Maybe the radiators aren’t so bad after all? You need a specialist who calculates that for you and also assesses the condition. What is currently used for heating? Gas?

By volume meter you mean those small great devices that hang on the radiators, right? Quote from my father: "You don’t want that thing hanging on the radiator, do you?" How to interpret that statement, I’ll leave to you.
Regarding underfloor heating: Would one be recommended in the basement? My parents prefer a warm floor and like to have warm feet. Since they do not get indirect heat like I do on the ground floor and they live directly above the ground. Can it be defined like that?

- Have you taken a close look at the roof? Is it in good condition? What about the gutters? All ok?

The roof was insulated from the inside, BUT if I looked towards the roof peak, I could see the open sky. At the spot where the dormer is installed, I could also look outside beside the windows. I have no idea how it looks under the current insulation.
I didn’t pay attention to the gutters, so I can’t say anything about them.

- What exactly is the problem with the electricity? And why new water?

Electricity: In one or another place, cables with screw connectors stick out of the walls…
The main fuse box is currently in the basement. Since both of us need our own fuse box with meter, the cables will have to be pulled from bottom to top anyway. Also, I want to control the blinds electrically in every room, the rooms with internet-capable devices (TV, PC, receiver) should be equipped with a network connection. Just little things.
Water: The bathrooms currently present look old. One bathroom will be enlarged, 2 bathrooms will be completely removed, and a room that is currently not a bathroom will become one. Pipes will need to be laid there, too. Also, there are many reports of water damage in our city. Whether at my parents' house, where I have witnessed 4 water damages in 20 years, or in my current apartment, which I have lived in for almost 3 years, I have already experienced 3 water damages. This apparently has to do with the water quality and is a well-known problem in the city that is hard to avoid. For peace of mind, a new piping system would be advisable. Convince me otherwise!

If I look at what you are planning, the finances are, in my opinion, not enough. I would at least double the budget.
Maybe you are also exaggerating with the "everything must be new" tactic. I first only see bathrooms and heating as the focus, and of course the attic conversion. Otherwise, just painting and fixing cosmetic defects first.
I would try to avoid an architect. As long as you don’t tear down load-bearing walls, you don’t need a structural engineer either.

I definitely thank you for your suggestions and contributions. But what would you do in my situation? Every tiled room has at least 2-3 broken tiles. Almost all doors have damage in the door frame or the lock area. The hallway is paneled with wood, which is missing in one or another place and I can see the masonry. How am I supposed to start with "fixing cosmetic defects" there?
Half work? If the tiles are going to be removed anyway so I can lay new flooring – "in the hallway laminate or similar" – then I can implement the electrical wiring with my ideas right away. Also for the electrically controlled blinds, lines have to be pulled for that, too. After that, I can start with the walls in the rooms. Or do I see a HUGE mistake I am making?

Thanks for your attention!

Year of construction, dimensions, wall thicknesses: to me, that almost "smells" like aerated concrete, though without guarantee, but highly likely. Possibly, depending on the overall package, even energy-saving ordinance compliant with the heating system.

Polish windows are said to be cheap: I cannot confirm that. After our own production, we still had external products in the range for a while. If the quality is "up to Western standards," the prices are only cheap, but not a huge bargain. Tearing out thirty-year-old "good PVC windows" (even if, in my opinion, that's already a contradiction in itself) for cheap Polish stuff would, to put it mildly, not be an upgrade, but at best unnecessary and useless. Just foil or sheet-metal the things if they are no longer nice enough for you.

"Too airtight causes mold" is basically true, but it's a gross oversimplification, and also not an argument against windows with better thermal insulation and protection values. Maybe can provide an assessment regarding retrofitting with rebate ventilation?

Overall, I strongly advise against even remotely considering the property a bargain. The age is particularly unfavorable: the stuff is not worn out enough to be really considered zero residual value and tear it out; but replacement doesn't cost less than if it were twenty years older. So the ratio of renovation effort to value increase is so skewed here that economically it already becomes a lover's object - but it is both suboptimal in layout and not enough of an architectural gem to be worth it.

As a businessman, I would quickly seek to make a fast getaway.

You want to turn a single-family house into a two-family house. I’m not very familiar with costs, but a renovation plus separating the living spaces costs more than just the renovation. I see it as at least double, if you don’t do everything yourself. But first, it should be clarified whether the development plan even allows a granny flat. Then, whether the criteria for living spaces can be met in the basement. -> ceiling height, light, etc., also parking spaces. But honestly: the house belongs to your parents now?! You’re supposed to buy it and renovate it the way your father wants. Is that correct? What he has worn out, you’re supposed to renovate expensively now?! I’ll put it this way: he will still see himself as the owner after the purchase. That will cause friction. I would keep my distance from the whole project. It already starts with the purchase price. And there are siblings too...

But honestly: the house now belongs to your parents?! ...And there are siblings too...

Um, yes. I'm sorry but I have no idea where you’re pulling this nonsense from.

We (me, my wife and my parents) have the opportunity to buy a house from a close relative.

The oldest of the children still lives there.

Have I expressed myself so unclearly?

But first it should be clarified whether the development plan even allows a granny flat. Then, whether the criteria for living rooms can be met in the basement. -> ceiling height, light, etc., also parking spaces.

Definitely a very good suggestion! I hadn’t thought of that at all!

Year of construction, dimensions, wall thicknesses: that "smells" to me almost like aerated concrete, although without guarantee, but highly likely. Possibly depending on the overall package, even up to current energy saving regulations with the heating.

In what way should I interpret the "smells"? As negative or positive?

How am I supposed to interpret the "stink"? As negative or positive?

That clues, in a certain density, are almost evidence.

Uhm yes. I'm sorry but I have no idea where you pull this nonsense from.

If someone replies to you and asks something or assumes something based on what they read, and gives you a tip, then that is not nonsense!

Your post is not exactly professional and error-free, so you shouldn't take such a tone here.
Have fun with your project!