Load-bearing capacity of L-stone and water drainage at 45° slope

Keep your head up and don’t despair. There is still no excavator on site! It will be fine!

As you already said, talk to the office to clarify their flexibility. Always use the argument of safety for you and your neighbors. Try to get in touch with the other neighbors to find out how they solved it back then / what problems they might currently have.

Please primarily clarify with the drainage of your upper neighbor (if necessary, the authority itself can also provide information here). The drainage is a specially backfilled trench with pipes that catch the (slope) water and allow it to drain off through the laid pipe in a controlled manner (preferably into a sewer). The goal should be to keep water away from your cellar / foundation, which is especially important on slopes.

Is your cellar made of waterproof (WU) concrete (white tank) or a so-called black tank (i.e. “only” sealed on the outside)?

And no, you are not too early with the planning of the outdoor area. Rather too late. It’s not about planning where which little plant should go. You are planning a massive modeling and you are right, that should be started now. The next person who rolls their eyes, just ask them how later the excavator, the building materials and the soil are going to be delivered and brought behind the house? Also for the further construction. Trust your gut feeling.

Keep your head up and don't despair.

It's getting increasingly harder, I can't say it any other way...

Thank you for all your messages and tips!

It can also be very simple, of course we armchair architects cannot really judge that, but you have definitely gotten an idea to ask further questions. Better to be startled now and then breathe a sigh of relief than to stumble from one expensive special solution to the next later on.

Have a maintenance shaft installed somewhere on your real channel (costs a few hundred euros, but is worth it). If you then let your cistern fill halfway there once or twice a year, you call that sewage channel maintenance or pipe flushing and that's it.

Have a maintenance shaft installed somewhere on your real sewer line (costs a few hundred euros, but it's worth it). If you then let your cistern fill halfway once or twice a year, you call that sewer maintenance or pipe flushing and that's it.

If the authorities really insist on it, they will certainly require that the cistern has an infiltration system. And if you actually have to procure and install it (perhaps the wastewater association wants to inspect it), you might as well use it.

With the seemingly attentive neighbors, this can backfire quickly. Then the house remains as is and the excavator has to be flown in by crane again quickly.