How precise does a construction start notification need to be and what happens then?

We are currently reviewing the document Baubeginnsanzeige (Bauort Sachsen). Does anyone know if the date must be specified exactly? We will start with the earthworks as usual, but the start depends on the weather (and presumably also on the availability of the construction workers). We were once given a calendar week, but not definitively.

As a first-time builder, I am also interested in what happens afterwards, what is done, whether someone from the building authority comes by, etc.

In Brandenburg, it was the case that within 2 weeks, from the date of the construction start notification, the surveyor had to perform the correctly positioned and elevation-accurate measurement of the foundation slab, or it had to be proven by means of a measurement certificate. (We didn’t manage that within the 2-week window)

Our surveyor pointed this out to us. But that’s the theory; if it takes 4 weeks, nothing will probably happen either, you just shouldn’t be off by months. ;-)

...so far I haven’t actively encountered anyone from the building authority, I personally think they only come for spot checks, if someone wants to pick a fight or is bored, although I almost exclude the third option. xD

PS: I believe that earthworks are preliminary construction measures and that the actual start of construction by definition is only with the concrete (foundation).

We are currently working on the construction start notification document (construction site Saxony). [...] As a first-time builder, I am also interested in what happens afterward, what is done,

As far as I have found (although it probably depends on the federal state) no other specification than "at the latest one week in advance," it apparently basically has to be done in advance – in this respect, I actually find the term "notification" misleading if it is actually an announcement. I assume that this "deadline" is related to the fact that the office wants advance notice to examine the suitability of the designated site manager. It is probably also expected to know from this person when further steps (such as commissioning surveyors, etc.) are to be taken. Presumably, you delegate the submission of the notification there already. The office needs to know when it is starting: a building permit is valid for several years; you can’t patrol every day to see if anything is happening yet.

In Brandenburg, it was the case that after 2 weeks from the date of the construction start notification, the surveyor had to have performed or provided proof of the location- and height-accurate survey of the foundation slab via a survey certificate. (We didn't manage that within the 2-week window)

Our surveyor had pointed this out to us. But that's the theory; if it’s 4 weeks, surely nothing will happen then either, just don’t be months off. ;-)

It wasn’t a problem for us either. Somehow, no one thought about it, and it was only done after moving in. No one reminded us in the meantime either.

For the construction start notification, I just wrote an approximate date. That was enough.

Off Topic: ;-) One more important thing I came across during my research. "Baubeginn" is a determinative compound noun made up of the nouns Bau and Beginn. :) As a first-time builder, you should definitely know that. ;-) I hope I was able to help other first-time builders with this.