Assessment of Renovation Costs for End-Terrace House from the 80s - Experiences

Hello dear forum colleagues. My wife and I have been looking for a house for quite some time and have now found this end-terrace house from 1980.

Some details about the house:

[*]Solid construction, 1980 according to the energy certificate
[*]142 sqm living space + basement, about 200 sqm in total and garage
[*]Plot approx. 780 sqm
[*]Gas heating + fireplace
[*]Energy efficiency class D 117.42 kWh/m2
[*]Price: 360,000 €

Apart from the conversion from oil heating to gas (1998), no major modernizations have been carried out in the house. Only surfaces, kitchen, etc. The windows, the roof and everything else are still original. If we buy the house, we would definitely renovate some things. Especially things that would make the house more energy-efficient.

The energy certificate mentions some recommended cost-effective modernization measures:

[*]Pipe system - insulation of exposed heating pipes
[*]Solar thermal - solar support for hot water and heating
[*]Windows - maximum Uw value of 1.3 [W/m²K]

So these are the measures we would definitely undertake. In addition, we would like to examine the possibility of installing a heat pump and some simpler things like new radiators, (new) roller shutters, etc.

Now to my actual question where I would like some tips, advice and experiences:

This is our first house purchase and especially a house that we need to partly renovate. We have no idea how to proceed with the process except to go to a credit broker and talk about financing. Do we have to inquire about the costs for the modernizations in advance and then pass them on to the broker, or do the brokers usually know what these measures would cost? Somehow it seems to me that creating an offer would take far too long if we talk to many different specialists from various trades and have to obtain detailed prices.

A few additional questions on my mind:

[*]As far as I know, the basement is always a risk because of moisture. The technology has progressed a lot and nowadays the risk should of course be lower. Are basements from the 80s generally future-proof, for example, and how can I find this out? Is there something I should ask about or look for in the building description?
[*]Roof and solar thermal: Here is a description of the roof from the building description: wooden beam roof with chipboard and underside boarding, thermal insulation according to DIN 4109, single-layer roofing felt and bitumen shingles in double coverage. This roof is 45 years old. I wonder how much longer it would last and whether it would be more sensible to renovate it at the same time if a solar thermal + photovoltaic system is installed?

I have tried to be as clear and organized as possible, but please let me know if I am misinformed about something or forgot to mention anything. And if anyone here has experience with houses from this period and has tips on what to pay attention to, check or assess, I would be very grateful.

Many thanks in advance for any help and experience!

If you replace the windows and doors, clarify (calculate) whether the dew point would shift into the wall as a result. This would then lead to condensation on the wall and ultimately mold. You can prevent this by insulating the walls.

In general: Do everything that causes dirt, dust, and trouble before moving in. You won’t want to do that once you are living there...

Addendum: Is the EEK calculated based on the demand or on the consumption? According to your description, I guess it's a consumption certificate, which is significantly less informative than a demand certificate. With the consumption certificate, you only see how much was consumed. If the previous owner lived in Mallorca for three months of the year or heated very sparingly (maybe even too sparingly), this results in a very favorable EEK for the property.

- Insulation of the basement ceiling from below (please insulate properly thickly - regardless of whether you then might have less headroom
- Replace window and door - 3-pane or 2-pane glazing doesn't matter, both windows will be hermetically sealed
==> please insulate the reveals inside with 20mm PUR or similar
- if the attic is only used for storage or similar, insulate the top floor ceiling (preferably a ventilated cold roof, then simply unroll 2x24mm mineral wool)
- whether you need to do the roof must be checked by someone
- omit solar thermal. It only causes costs with very little benefit
- fully install photovoltaic on the roof, if the budget allows
- if roof/attic and basement ceiling are insulated or new windows are installed, a heat pump is easily possible
==> have a room-by-room heating load calculation done and install corresponding radiators (33 type)

Of course, much more can be done, but it's all a matter of budget

insofar as the attic is only storage

Mansard roof with high "KS" and apparently fully developed. There apparently is no attic. Clad with shingles and end terraced house.

I didn’t renovate, but I bought an unfinished house (walls, roof present).
At that time, I requested quotes for almost all items, at least if a company had to be commissioned. For others, I set a budget (e.g., if only materials had to be purchased). For some smaller items, there was only an estimate in advance. I had a site manager anyway; he entered a figure here. And with the resulting list, I went to the bank.
You have two options: either you consider what you want to renovate, get quotes, and thus come up with the necessary budget. Or you say, maximum sum x, and you have to prioritize the renovation work and see what you can accomplish within x. Also here by obtaining quotes.

That would then lead to condensation on the wall and ultimately mold.
You can prevent this by insulating the walls.

With a ventilation system (decentralized), one could also avoid this, if I'm not mistaken?

Is the EEK calculated based on demand or consumption?

Thank you for the post. Exactly. The numbers are based on a consumption certificate. The question is, if no demand certificate is available, how can the buyer find out?