Quote from @Jonathan Orr:
I would think it would depend what state the plans are in. If they are 100% done and approved, that seems high to me. for 75% completed plans for a industrial project I was quoted around 2-3k for a budget, this was for a 65k sq ft industrial center.
I found estimators on a website called upwork. I ended up just going to the GC I was going to hire and they assisted me with a bid/budget.
My question is why don't you go to the GC that you intend to have build it and get them to provide you with a budget?
Hope this helps
Jonathan - thanks very much, very helpful. As it happens I did end up going to upwork, and quotes there ranged from $1k to $3.5k, so you were right that $4k was high! I'm using the estimator numbers to check all the sub pricing from my GC, i.e. to work out if I need to have him go and get more bids from subs for particular trades (or negotiate his preferred guys down).
In terms of paying my GC, I'm hoping he'll be okay with 12-13% profit on hard costs (with no additional overhead). I'm told by others this might be on the low side, with some GCs wanting 10% profit and 10% overhead. What would you think is reasonable? We may operate this as a cost-plus contract, trying to lock down as many of the sub's prices upfront, but knowing any justifiable increases will be passed on to me. Would that seem reasonable?