Done project management before. I like it but if a contractor or a sub-contractor is duff then they are duff, not much else you can do apart from telling them they are not being paid until they do the job right. If it comes to the worst show them the door and tell them if they want their money they can try taking you to court where you'll point out that they did a sub-standard job and, despite having their mistakes/poor work flagged up and being given ample opportunity to rectify their work they still left a mess. They wouldn't have a leg to stand on.
The job of the PM is to contract out the work to the main contractor (in some instances organise sub-contractors), oversee the work and sort out payments. A PM can't be on-site constantly so there are going to be things that you can't see until finished however a good main contractor will be on top of their subies and will sort out any issues without having to hassle the PM too much. Snagging a job is always fun especially with a contractor who is in denial.
As for payment, I have only once had to ask for part of the cash up front from a client and that was because the property was owned by a company and had recently been bought by on of the tenants. Normally you retain a percentage (the value of the retention monies varies between different types of contract) of the final account to cover the defects liability period (again this varies depending on the contract) and use it as an incentive for the contractor to come back and fix any problems which occur once they are off-site, but only if they have been caused by the work.
Chatet?
RC is typing with her feet again... she must have just gotten her nails done.
