Responsibility for compliance with the development plan in turnkey construction

Hello forum,

who is responsible for ensuring that the regulations of a development plan are complied with when building "turnkey" (including planning etc.) with a construction company?

The client (as a layperson in construction) or the construction company (as the executing and planning service provider)?

Specifically, it is currently about roof tiles that may not be permitted by the development plan. These were selected by me (client) without (unfortunately) checking the development plan again....

Regards N.

Hello,

....who is responsible for ensuring that the provisions of a development plan are complied with during "turnkey" construction (including planning etc.) with a construction company?

The planning authority lies exclusively with the client, i.e., in external relations, he must take responsibility for all effects arising from the construction project.
Since a client is usually not an expert, he delegates to the general contractor / subcontractor, architects, etc. There is then a contractual agreement between the client and the contractor.

....Specifically, it is currently about roof tiles being installed that may not be permitted by the development plan. These were selected by me (the client) without (unfortunately) checking the development plan again....

The general contractor / subcontractor must deliver a defect-free work. This also includes that the building complies with the development plan requirements.
The general contractor / subcontractor should have pointed out during the selection that the chosen option does not comply with or violates the concerns of the development plan. A negligence on their part.

Best regards