Are building permits required for basement construction?

Hello everyone, I have a very important question for us. So far, all the architects in our circle of friends have given opposing answers but maybe someone here has experience with our problem. We are going to build an end-of-terrace house. The neighboring houses are all being built by the same developer. (He only bought the plots after we already had ours, so we couldn’t get out of the contract anymore!) Now this developer is building the row without a basement but we want to build a basement. (This is also possible there!) Now our problem, who has to accommodate whom at the start of construction? :-? That means, is there a regulation in building law according to which we are allowed to dig the excavation for the basement first or does the developer have to go first and we have to support their slab? That would mean high additional costs. We would be very grateful for any information! Regards

Now it’s getting tricky.
Connection of non-basement buildings and basements, or vice versa, doesn’t really matter if done correctly.
For the non-basement area, the foundation must be stepped down to the base of your basement floor slab, depending on structural requirements, soil conditions, wall thickness, etc.
This means that if the neighbor starts building before you, he should found his strip foundation on the basement wall adjoining your property (party wall) down to the depth of your floor slab. The other foundations should then be stepped depending on the soil up to about 10 cm above ground level. This way, you can also start later than him.
It’s certainly important for you that the neighbor is checked, so once your plan is approved, you should kindly inquire at the office about how to proceed. The neighbor has to found more elaborately because of you, but that’s not your fault, since he could also build with a basement. Mistakes are often made here :-o and/or savings are made in the wrong place. ;)

Hello Bausepp

thanks that already helps me.
The problem is apparently that there are no
universally valid rules. Our architect
told us that whoever builds the basement is out of luck and a friendly architect said
the same as you!
I think I will inquire early at the building authority
to see what they say about it!

Do that, for me building permits have also been made dependent on neighboring development. Ok., it was a bit unusual, the second semi-detached house should match the style. The principle is the same, consideration of neighbor's rights, in this case also your right!

So, instinctively, I would make the whole thing dependent on the timing of the granting of the building permit. That simply means whoever submitted the building permit first or received it first, in my opinion, has the better cards. The architect must also inquire about what is planned on the neighboring property when planning. If it is clear that a house with a basement will be built there, he must take this into account in his planning, especially for the foundation. However, if there is no planning yet, he can, except for requirements from the building authorities, decide freely how he wants to lay the foundation of the house. As I said, this statement is not legally based but just instinctive!