cost of project management for house renovation

Does anyone have any experience with project management and spec costs for a house renovation. This consists of a re-config of a basement to sort out water problems, and a small extension.

I'm not using an architect, as I knew pretty much what I wanted. I am getting a surveyor/engineer company to draw up dimensioned plans and a spec for the tender. To do this and supervise the work they want 10%, which comes out about e10k.

I would prefer they charge by the hour, 10% seems excessive to me for the hours they are putting in, and the critical pieces of the spec are to be guaranteed by the builder (drainage, pumps to avoid future flooding, damp proofing, heating). The engineer with the company did spec the steel beams necessary, and they are spec'ing all the building materials.

Many thanks.

You could use a building service that project manages and is happy to engage with your engineer on any details that need refinement.

Even if you nominate the subcontractors a competent builder/project manager would manage the services under his / her remit and ensure that all the enabling works occur at the correct time within the schedule. Through site management the individual works (drainage, pumps, damp proofing etc) would be checked, tested and signed off before hand over to continue works.