Build a new house on an old cellar

Hello,

to ask my question, I have to give a little background.

We live on a 600 sqm plot, on which there is a settlement house from the 1950s with 140 sqm of living space (the upper floor is empty, we use the ground floor as storage and hobby space). In addition, a "extension" with 150 sqm (18 meters long and 5 meters wide, 2 floors) is attached to the settlement house. We live in this "extension" with our two children. Both houses are connected to each other directly on the ground floor.

The extension is from 1970 and in top condition. We have completely renovated it. It is connected to the heating system of the settlement house (oil condensing boiler from 2010).

Now, due to the layout (long and narrow), we have three bedrooms in the extension, one of which is only 9 sqm, the other two are each 16 sqm, and there is also a lack of a second bathroom. Therefore, we want to put the master bedroom with a dressing room in the settlement house.

However, if we want to use the settlement house for living purposes, a lot needs to be done.

1. The roof is from the 1950s and is not insulated.
2. The facade is made of 1930s pumice stone, it would need insulation.
3. The ceilings are creaking wooden beam ceilings; something would have to be done here.
4. The electrical and water lines would also have to be redone.
5. New front door...

Now I am wondering if it would make more sense to tear down the settlement house and build a new house on the old basement, which protrudes 80 cm from the ground. Same dimensions as currently. In the new house, I would only install one bedroom, a dressing room, and a bathroom. The rest would remain unfinished and empty (until one of the children is old enough).

What do you think? Is it financially the better solution to renovate, or to build a new house?

Best regards from Untermain,

Linus

This is here your "first" post, but it still seems to me as if I have already read this case constellation (in the previous year ?) once before in this or another builders' forum (?)

Both houses are directly connected on the ground floor.
[...] the heating of the settlement house (oil condensing boiler from 2010).

From this I read: the heights resulting from a rebuilding of the existing basement would be suitable for you; and in terms of connection technology the basement would not need to be changed either.

Your question is therefore actually – not as usual whether the basement is suitable for further use – the consideration only concerning the above-ground floors of the settlement house, whether it is better to renovate or rebuild.

If the basement is indeed "still good" – that is not "only good enough as a heating cellar" – then I would tend to rebuild.

However, if the usage changes from "the upper floor is empty, we use the ground floor as storage and hobby area" only to "more spacious sleeping and bathing in the ground floor, the upper floor would be storage and hobby area," then there is a considerable question mark on the economic efficiency.

Under these circumstances, an energetic renovation seems to me to be limited to the ground floor (with the upper floor as an "attic" and insulated ceiling as a boundary) and I wonder how much floorboard creaking from the upper floor one would actually have to endure in bed and bath there.

In fact, I am also considering this option. For me, it is the case that I have done all the manual work myself so far. I am a trained carpenter and now work in an office, so in my free time I also like to do some physical work. I have done the electrical work, plastering, tiling, and other renovation measures myself so far. Therefore, I am not sure what would be cheaper for me in the long run, to renovate the house or to have a shell construction built and then gradually expand it.

the basement is purely a heating cellar; it contains the heating system, domestic hot water heat pump, oil tanks, power supply and fuse boxes, as well as water and sewage that run through this cellar.

I completely replaced the windows 3 years ago. If I were to rebuild, I would want to keep these windows. (3fach verglast)

the cellar is purely a heating cellar

I did not mean whether it is a utility or residential cellar. Rather, that with a heating and house connection room usage, for example, one does not pay much attention to uncritical material defects; with food storage one does pay more attention; and a residential cellar is then the highest level of demand.

If I were to build new, I would want to keep these windows.

Yes, the damage when removing usually only affects the reveals; the windows themselves can usually be taken away undamaged. One could pay attention to suitable opening dimensions.