House financing KfW 300 & 124 - please provide an assessment

Rainwater connection will not be made.

Then the downpipes stop at the top edge of the base slab.

Rainwater percolates on the property.

And how? It must be directed there. however..

I don’t see it as so critical with the roof area.

.. the building authority cares about that. You are no longer allowed to let rainwater simply percolate on the property like that, but that only concerns the property. And property matters are not the affairs of the construction companies.

Many words for a small topic among many.

I do not expect such high heating costs for a KfW-funded energy-efficient house.. (underfloor heating, air-water heat pump)

You don’t get a KfW house heated for free either. It’s not as if I or the others here, who have been dealing with house construction for several years until today, are completely outside the field.

.. the building authority is not interested in that. Rainwater may no longer simply be allowed to seep away on the property, but that only concerns the property. And property matters are not the concerns of the construction contractors.

I don't know which federal state you mean. In Lower Saxony, rainwater must be retained or infiltrated on the property (Lower Saxony Water Act + WHG).

But we are far from the topic. It has become clear to me that you consider financing of this amount to be unrealistic. I will post again here as soon as I have an approval or rejection.

I don't know which federal state you mean. In Lower Saxony, rainwater must be retained or infiltrated on the property (Lower Saxony Water Act + WHG)

And that not only costs a device in Lower Saxony to allow rainwater to infiltrate. And that also costs money, bringing us back to the topic.

But we are far from the topic. It has become clear to me that you consider financing at this level to be unrealizable. I will post again here as soon as I have a confirmation or rejection.

As long as your calculation is incorrect, you should not request financing, but first ask what you can actually finance. And then you can start calculating.

In Lower Saxony, wastewater must be retained or infiltrated on the property (Lower Saxony Water Act + WHG)

How exactly are you solving that again? Terrain basin with a infiltration trench or cistern? Those are costs I don’t yet see in your calculation. It’s one of the points not included in the house price. Add about 5-10k for that.

How exactly do you solve that again? Terrain depression with soakaway or cistern? Those are costs I don’t yet see new in your calculation. It’s one of the points not included in the house price. Add about 5-10k for that.

Here in the new development area (Lower Saxony, construction year 2023-2025) most neighbors paid around 10,000 for the wastewater connection as well as for rainwater infiltration on the property (sewer connection prohibited). This is done either via a kind of buried gravel pit made of concrete shafts or a soakaway. A soakaway of the size to drain about 200 sqm of roof area costs you only material roughly 5,000 euros without labor costs for installation and earthworks. A cistern with 10,000L also 3,000-5,000 euros. If you want to do it yourself, the excavator rental also costs a few hundred and the excavation has to go somewhere. It’s unfortunately not that simple, otherwise your house would flood with every heavy rain.

@ I have a question about the KfW topic: - Do you take advantage of the funding because you want to build energy-efficient anyway, install a controlled residential ventilation system, etc., or - Do you want to build to the KfW standard because you hope for savings with the KfW loan. We have now been planning for a long time and for us, the KfW planning only pays off because we wanted to build to such a standard anyway. The measures are not without cost and the energy consultant always costs money, regardless of the project's volume. Therefore, I would question whether you really have a financial advantage.