Check cost estimate from preliminary draft

Friends of ours have just newly accessed the basement via an external staircase. However, the costs were five-figure.

And of course, everything is very regional and dependent on taste. For example, it says railing 750€. Our total 4m long aluminum railings on the upper floor cost 4,000€ including installation.

- Heating (gas condensing boiler) remains, piping stays in most of the house, only the attic gets new heating pipes due to conversion. There will be underfloor heating there, the rest of the house will have normal radiators

You knock out the screed and leave the radiators in? That’s really half-hearted, since with the underfloor heating, even the removal of floors/screed as well as the new screed including floor coverings is encouraged. Not to mention the energy benefits, the comfort factor, and walls freed from radiators.

- Electricity mostly remains as well, the fuse box will be new and in the attic due to the conversion

I don’t understand that either. Why? Is the electrical system already so new and comprehensive (modern)?

- Basement stairs: Our architect apparently wanted to achieve KFW55, but had to revert to KFW70 because according to his calculations it was not sufficient for KFW55. Exterior basement stairs are also not my favorite, especially since there is basically no space anywhere for the stairs...

Then he should be flexible and adjust other parameters.

In addition to the electrical system, is networking not planned to bring the house up to date?

No, we do networking via Mesh WLAN, works perfectly and our devices don’t have any ports anyway...

Regarding underfloor heating: full agreement, I thought I had too high demands for a preliminary draft, but for me there is clearly too much half-baked stuff in it...

No, we do the network via mesh WLAN, works perfectly and all our devices don't have a port anyway...

I can only advise you to at least do basic wiring across the floors. Since you rely only on WLAN, you need access points for good WLAN coverage and they require LAN. For such a major renovation, repeaters are a no-go for me. You don't need LAN everywhere, but it's highly recommended at a few locations with fixed devices. Like TV, office, children's room.

I can only advise you to do at least one floor-spanning basic wiring. Since you rely solely on WLAN, you need access points for good WLAN coverage, and they need LAN. For such a large renovation, repeaters are a no-go for me. You don't need LAN everywhere, but in a few places where there are fixed devices, it is highly recommended. Like TV, office, children's room.

Thanks for the recommendation, but the access points don't need LAN; they are in the mesh and thus form a unified network... Connecting the access points via LAN is possible but without advantage. The bottleneck in our house is the 70 MBit DSL connection, not the data rate between access point and router.