Split-level from 1967 - experiences?

Unfortunately not possible, because multigenerational living is a "must-have" criterion for us. We would turn the entrance, hallway, and the two lower left rooms on the plan into the apartment, but we need more space than they can offer us. My mother is still quite young and definitely needs more than one room. We lack the imagination of how to conjure up a sufficiently large apartment from about 45 sqm. But phew, 60,000 EUR is quite a sum. We'll have to see, maybe we'll find another solution than the extension...

Then why is a multigenerational house a "must-have" criterion? A young and fit mother doesn't necessarily have to be integrated into the main house - and on such a large area at that. Can't she continue to live alone, like all normal young mothers do?

One way or another, you will have to decide:
- Mother gets a 45 sqm studio apartment (professionals can turn that into three fully equipped micro-apartments)
- Mother lives her nice life without annoying children next door (and vice versa)
- You just take the (non-existent) money in hand and remodel or even further enlarge the already huge 240 sqm house (for three people!)

Why is a multi-generational house then a "must-have" criterion? A young and fit mother doesn’t necessarily have to be integrated into the house - and on a large area at that. Can’t she continue living alone, like all normal young mothers?

My mother lives 300km away and would like to see the little grandchild regularly. Besides, it is simply our wish to have her close to us, and instead of a house + an apartment nearby, we want to realize that under one roof. Therefore, we are explicitly looking for something that is feasible for us with (currently) 4 people.

You will have to face one of the following: - Mother gets a 45sqm studio (professionals turn that into three fully equipped micro-apartments) - Mother lives her beautiful life without annoying children nearby (and vice versa) - You just take the (non-existent) money in hand and rebuild this already huge 240sqm house (for three people!) or expand it even further

At the moment we are leaning towards death number 1

We lack the imagination of how to conjure up a sufficiently large apartment from about 45 sqm. But phew, 60,000 EUR is quite a sum. We'll have to see, maybe we'll find another solution than the extension...

KfW261 can also be used for extensions and expansions. The extension is practically funded 100% (except for civil engineering), if at the same time an efficiency house standard is achieved overall. If 2 residential units result, the maximum funding limit is correspondingly 300,000 EUR if the EE class (heat pump) is reached. The grant is then with KfW 85 10% + 10% if it is a WPB (energy certificate class H), so 20% and of course the lower interest rates.

Unfortunately, that was correctly guessed. It is 36.5 cm sand-lime brick. We were misled by the facing brickwork. And without facade insulation, the efficiency house standard 85 probably won't work, right?

Efficiency house means every component of the thermal envelope must comply with the Building Energy Act requirements or justified exceptions are possible – 36.5 cm sand-lime brick is not sufficient. For an efficiency house, about 14-16 cm ETICS or similar must be applied.

Regardless of the efficiency house issue, a 36.5 cm sand-lime brick wall is energetically... difficult to call sufficient. If the facing brick facade is to be preserved, this can also be solved with an 80 mm internal insulation (wood fiber), but this is only the second-best solution, costs living space, and KfW85 could be difficult.

KfW261 can also be used for extensions and additions. The extension is virtually 100% funded (except for civil engineering) if an efficiency house standard is achieved overall at the same time. If 2 residential units result, the maximum funding limit is correspondingly €300k if the EE class (heat pump) is achieved. The grant is then 10% + 10% at KfW 85 if it is a WPB (energy certificate class H), so 20% and of course the lower interest rates.

Efficiency house means every component of the thermal envelope must meet the building energy law requirements or justified exceptions are possible – 36.5 cm sand-lime brick is not sufficient. For an efficiency house, about 14-16 cm of ETICS or similar must be applied.

Independent of the efficiency house issue, 36.5 cm sand-lime brick masonry is energetically ... difficult to describe as sufficient. If the clinker facade is to be preserved, this can also be solved with 80 mm internal insulation (wood fiber), but it is only the second-best solution, costs living space, and KfW85 could be difficult.

Thanks for the info, very informative!

Exactly, we also assume that we could get the full €300k in eligible costs together – plus quite a bit of non-eligible stuff. Although, for example, I am not sure about the tiles in the bathrooms regarding eligibility.

That sounds like we will hardly get around ETICS... Maybe it could be reclad with clinker afterward – or work with thin brick slips?!

Two good observations! Regarding the double-shell construction, I have already pulled my own tooth, it seems to be interlocked, but not double-shell. Very unfortunate, because I like the look of the facade as it is, and ETICS drives the budget up. Plus, the roof overhang is not present everywhere, and if you had to start extending the roof... I lack the imagination of how that should be feasible within the budget.

Especially with a flat roof & in combination with the roof insulation already planned, it should be quite simple.

Depending on the execution, remove (masonry) parapet & then form it, for example, from insulation panels (provided no fall protection needs to be created this way). The "fake parapet" can also be installed with an overhang so that the facade insulation can connect flush underneath.

Alternatively, insulate the existing parapet and line it with correspondingly long parapet boards/crown insulation.

Especially for flat roofs & in combination with the insulation of the roof already planned anyway, it should be quite easy.

Depending on the design, remove the (masonry) parapet & then form it, for example, from insulation panels (provided that no fall protection has to be created). The "fake parapet" can also be installed with an overhang, so that the façade insulation can connect flush underneath.

Or alternatively, insulate the existing parapet from above and line it with correspondingly long parapet beams/crown insulation.

Thank you for the explanation! It is really great how much expertise is gathered here.