Renovation measures on the house and associated obligations

Hello everyone,

I inherited a house two years ago, which I have been renting out since then. Now I want to use it myself for starting a family and renovate it. Regarding the basic data:

- approx. 130 sqm
- fully basemented
- clinker brick façade
- built in '76

Before renting it out, I renovated the floor coverings and completely refurbished two bathrooms. Now I want to build an extension and have an appointment at the building authority for a preliminary clarification. The building plot basically allows for the extension.

What I have imagined so far:

- extension to gain living space (I spoke with an acquaintance who knows a bit; of course, an architect and structural engineer will still need to be involved)
- new or additional windows (remove masonry and install floor-to-ceiling windows)
- completely re-clinker the façade
- new floors inside, etc.

Now to my questions:

Do I have to consider any issues regarding energy regulations during the renovation, i.e., will I be obligated to carry out certain measures?

What about insulation? I would put the clinker façade on top of the existing one. Is this sufficient as "insulation" or should it be additionally insulated in a sensible way? How can one possibly prevent the window reveal from becoming too deep? The basement is made of sand-lime bricks. The ground floor and first floor are made of aerated concrete.

The house has copper pipes installed. Should renovation needs be expected here, which would be reasonable to address now? According to the opinion of an electrician, the electrical system seems to be good. So I would only have additional sockets installed.

I would be happy if we could discuss my project a bit here.

These are exactly the questions that an architect can and should answer for you. We are currently renovating a house from 1962 as well. I wouldn't dare take it on without an architect. Have a few conversations and maybe have the effort estimated by the architects. Then you usually know where you stand. Most architects conduct the first meeting for free, and then you know what to expect. Yes, you have to comply with the [Energieeinsparverordnung], but of course, there are exceptions.

Does the architect have to go into the house for this? Otherwise, he won't be able to assess the condition, right? I don't really want to scare the tenants before a final decision is made.

In order to roughly calculate some things, he does not necessarily have to go into the house. However, it would be highly recommended. But with the help of many documents and photos, it should also work.

ok, the first step should be to clarify with the building authority whether the approach is basically possible. is an additional layer of bricks sufficient as insulation? probably not, right?

we have already been to several developers. we are now relatively clear about what we want to do structurally. we will build an extension and insulate and re-clad the entire house, install new windows, and renew the roof. these are the main points.

now let's start with one point:
clinker:
we have focused on two color variants. either "perlweiß bossiert" with light mortar or a smooth stone in "burgundy" (it's hard to describe the color, but it is quite common in new housing developments). since we will have different roof pitches due to the renovation, the house will have a shed roof.

now we have two questions. are there differences in the clinker bricks of the same price range based on color? does bossiert get "shabby" faster than smooth, and does white get dirty faster than a darker, colored clinker?

also your individual opinion once again: white always looks somewhat elegant, classic. does a modern roof shape like the shed roof fit with such a classic stone, or would you rather choose the darker tone when deciding between the two stones? i am not so sure how the shed roof looks with which clinker. unfortunately, i have only ever seen white plastered shed roof houses in person.