Cost estimates terrace, fireplace, support beam, window, bathroom

Hello everyone,

we are currently looking at a house from 1951, but everything has been renovated and refurbished in the last 10 years, roof, heating, etc.....

We still want to make a few changes and for that, I just have very rough values for my current rough calculation... I need to know if something will cost around 50k or only 10k in the end, and I don't know much about this.

1. From 3 narrow terrace doors that lead individually to the terrace over more than 3 meters with some distance between them, there should be one large lift-and-slide door, so also masonry needs to be removed, the new door, etc...

2. There is currently an aluminum chimney pipe running through the apartment, so there is a hole in the ceiling between the ground floor and the top floor and also between the top floor and the attic, then it goes out through the roof... looks pretty stupid. Can such holes be closed again and also so that they are load-bearing again, so you can put flooring on it, etc.? Costs?

3. On the ground floor, a total of 3 walls should be removed to make the rooms more open, I don't currently know which ones and whether they are load-bearing, I think 1 or 2 are load-bearing, so a support beam / steel beam would have to be installed?! Also here just rough costs for removing a wall, what should be budgeted for that

4. Possibly also enlarge 2 or 3 windows, meaning remove them, take down more wall, put in larger ones (the exterior facade is currently clad in plastic and will have to be redone anyway sometime, so these things can be neglected for now)

5. A bit complicated to explain: Upstairs there is a bathroom, next to it a small bathroom with only a toilet, and in front of that is a hallway. A piece of the hallway should form a new large bathroom together with the two bathrooms, so also 1 or 2 small walls removed, a new small one added, everything removed from the bathroom and new things put in again.

Of course very vague, because it’s about details... but just normal standard... I don’t know if something like this is about 5k or 20k...

6. Outside there is a concrete pool, next to it some terrace slabs. This whole area should create a platform with wood and a new surface so that the pool is permanently closed at first (small children) and can be refurbished later (it already looks in need of renovation). Area approx. 10x3.5 meters and of that 7x2.5 are air space of the pool.

I know this is all quite vague, gladly averages... or also a range...

1. From 3 narrow terrace doors that lead individually to the terrace over 3 meters with some distance, a large lift-and-slide door should be installed, so also masonry removed, the new door, etc...

Depends on whether the structural engineering still supports it. I would ask a window manufacturer, they often have structural engineers for smaller things like this on hand, who then work overall cheaper, etc.
Such things are always hard to estimate, for example if an I-beam has to be installed, etc.
I estimate it would be possible with 10,000€ though.

2. Currently, an aluminum chimney pipe runs through the apartment, so there is a hole in the ceiling between the ground floor and top floor and also between the top floor and attic, then out through the roof... looks pretty stupid. Can such holes be closed again and also made load-bearing again, so that you can put flooring on it, etc.? Costs?

You can do a lot, I can't really judge what it would cost. I think one should not forget that this will probably also require floor renewals around it.
10,000€? maybe, 50,000€ rather not.
But I would rather refrain from giving an opinion :)

3. In the ground floor, remove 3 walls in total to make the rooms more open, currently don’t know what and if load-bearing, I think maybe 1 or 2 are load-bearing, then there has to be a support beam/steel beam?! Also just rough costs for removing walls, what you should roughly calculate for

11 cm walls + some plaster are normally not load-bearing, as long as they connect to a thick outer wall or a thick inner wall. Load-bearing walls are usually also aligned above and below on the floors.
In my opinion, these are only things that provide a rough reference. Better to consult a specialist.
Knocking out walls? -> big sledgehammer and off you go. Removing one or several walls is quite doable as a DIY job.
The expensive part will rather be screed filling/patching, or if heating pipes run through the walls. Maybe here and there something for electrical work has to be done.
I think all in all that can be done with 10,000€. If you do some yourself, definitely would say so.
If support beams or I/Double I-beams have to be installed, then probably over 10,000€.

4. Possibly also enlarge 2 or 3 windows, so out, more wall removed, bigger ones installed (the exterior facade is currently covered with plastic cladding and has to be done anyway sometime, so these things can be neglected for now)

If the window manufacturer comes for question 1, you can mention this at the same time. Windows are expensive but not insanely expensive either.
If structurally possible, it surely won’t cost 10,000€, I’d rather say 4,000€, although I don’t know how big the windows are supposed to be, etc.

5. A bit complicated to explain: Upstairs there is a bathroom, next to it a small bathroom with only a toilet, and in front of that a hallway. A piece of the hallway is supposed to form a new large bathroom together with the two bathrooms, so also remove 1 or 2 small walls, build a new small one, remove everything from the bathroom and install new things.

Is of course very, very vague because it’s about details... but just normal standard... I don’t know if something like this costs about 5 or 20k...

I’m doing something similar right now, combining a small WC with a bathroom. So one wall out, door bricked up, screed out (you probably won’t get around this).
I have the pipes done professionally. I will remove the wall and lay the screed myself, just like tiling, etc.
New bathroom/WC setup (toilet, large shower, bathtub, washbasin, 10 m² area) + pipe installation 13,000€. Will be more than DIY store quality though.
Total cost probably around 18,000€.
Just calculate around 20,000€.

6. Outside there is a concrete pool, next to it some terrace slabs. This whole area should be made into a platform with wood and create a new surface, so that the pool is closed permanently for now (small children) and can be renovated later (it already looks in need of renovation now). Area about 10x3.5 meters and of that 7x2.5 meter is empty space from the pool.

Certainly under 10,000€. Usually, you can do something like this yourself.