Structural engineer and proof engineer: What is the difference?

When building, the four-eye principle applies: the structural engineer plans and calculates, the proof engineer (Prüfstatiker) checks independently. Understanding both roles helps to plan the approval process correctly.

What the structural engineer does

The structural engineer, or structural designer, is commissioned by the builder. They develop the structural system, perform the structural calculations, and create the execution documents. They are part of the planning team and work closely with the architect and specialist planners.

What the proof engineer does

The checking engineer for structural stability is state-recognized and independent. They check the submitted structural calculations on behalf of the building authority: Are load assumptions, calculation methods, and construction plausible and compliant with standards? The structural calculations only become effective in the procedure with their test report.

When verification is required and when it is not

Whether a check is required depends on the building class and level of difficulty. In Baden-Württemberg, simple projects sometimes manage without an external check, while larger residential, office, and special buildings generally do not. Your structural engineer will tell you in advance what applies to your project.

Why interaction matters

An experienced structural designer delivers verifiable documents that minimize queries and quickly answers the checking engineer's comments. This keeps the process on track. Both roles are not competition, but double security for the builder.