ᐅ Include costs for structural engineering approval in your budget.

It depends on where you are building. We are currently building in the Tübingen area, and here we MUST commission a structural engineering review to obtain the building permit / planning permission approval. In addition to reviewing the plans, occasional site inspections are also required.
This is due to seismic zone 3 – here is a link from Reutlingen, which lies right on the border.

• Technical construction proofs (§ 9 LBOVVO)
• • Structural stability proof
  • Sound insulation proof

Explanation of the structural stability proof (§ 10 LBOVVO) Note: Reutlingen is divided into seismic zones 2 and 3. Seismic zone 2 includes:
Sickenhausen, Altenburg, Rommelsbach, Sondelfingen, Reicheneck, Oferdingen, and Mittelstadt.
In seismic zone 2, a technical construction review (structural engineering review) is generally only required for larger commercial or agricultural projects and larger residential buildings.
Seismic zone 3 includes:
Reutlingen – city center, Bronnweiler, Degerschlacht, Gönningen, Ohmenhausen, and Betzingen.
In seismic zone 3, a technical construction review is basically mandatory for all building projects with occupied rooms or commercial/agricultural use (§ 18 LBOVVO).

This means a structural engineering review MAY be mandatory for your building project in Baden-Württemberg.

So far, we have only paid for the plan review; the site inspections are still pending. The fee depends on the volume of the enclosed space. We have estimated about 3500 euros.

Thank you for the responses. We will be building in Schömberg, which is in seismic zone 0. That gives me hope that we can skip the structural engineering review.