-
Depends where you are & the spec you're after but we're in the middle of a D&B c3m x 5m extension, knock-through & new kitchen in London - 150k was the very punchiest quote we got which we took for them just not wanting to do it. Most of the others were in the 80-120 range.
Also despite having a project manager, you do also have to do a hell of a lot of project managing anyway - the building co PM essentially just buys the stuff & makes sure the labourers turn up.
Objectively it is crazy, yes, but that appears to be what these things cost if you don't have the desire to self-manage.