ᐅ Partial Renovation of Older Building: Electrical, Bathrooms, Flooring... Questions and Progress Thread

Hello everyone!

We recently bought a single-family house that had supposedly been renovated, including outbuildings and a nice plot of land.

Key details:
Old building, construction year unknown – renovation and extension in 1961 – renovation from 2016 to 2018, garage construction in 2018
Approximately 160 m² (1,722 sq ft) of living space, 540 m² (5,813 sq ft) plot, double garage, and the Heinrich – our outbuilding.
There is a partial basement with a deep vaulted cellar (ceiling height about 160 cm (63 inches)) and a heating cellar, above that the ground floor and first floor, and a partially converted attic.

We knew from the start that it was not a high-quality renovation. Everything is cheap plastic, many different types of flooring and switch series (just whatever was on sale at the time), everything half-finished. But: basically, everything was done – insulation, new windows, all walls drywalled and plastered, new heating system and radiators, new water pipes, partly new electrical wiring, partly a new roof, solar thermal system.

So far, so good. Visually, there is still a lot to do, it absolutely was not to our taste, but that seemed manageable. The bathroom on the first floor was going to be redone, a partition wall on the ground floor removed, the floors on the ground floor replaced with uniform tile flooring... paint and move in. Gradually work on the garden and perhaps eventually change the floor covering on the first floor or renew the wiring.

Now that we have been living in the new house for two weeks (currently still parallel to the rental apartment until the end of the month), we realize: 1. Painting and moving in as planned won’t work. 2. Man, this is taking forever! We seriously underestimated the effort.

Unfortunately, there is interior insulation everywhere. When removing wallpaper, we discovered a moldy base area in the living room. So (most likely): all walls must be stripped down, mold treated/dried out, replastered. We have an expert coming to the house next week.

The electrical system needs to be redone. There is only one ground-fault circuit interrupter (GFCI) for the stove, none for the bathrooms, too few circuits (there might be enough circuits, but most outlets and lights are connected to just one breaker). There are some Swiss-style outlets with three holes. The previous owner seemed reluctant to use grounding. The main cable comes over the roof, which we also plan to reroute.
The data cables just come out of the wall. Electrical boxes were probably too expensive or simply unavailable at the time – who knows... We are undecided whether to do a complete overhaul or tackle it room by room. We have an electrical engineer among our acquaintances and may work out a plan with them.

Overall, the house is quite botched. Ventilation of wastewater pipes? Who needs that? Eight sockets in series on one cable? That’s handy for a workshop! A toilet or a washbasin in the bathroom? Totally overrated! The fans in the attic don’t work? Doesn’t matter, the humidity will just escape into the roof insulation. Oh, foam sealant? Yes, THAT was a favorite! And rough plaster? Lovely to paint (not), and ugly to boot.

Why am I writing this?
I’m hoping for tips, experiences, maybe some planning suggestions for the kitchen and bathroom, and otherwise, I’d just like to share in case anyone is interested.