How many times have you been asked to carry out works that are either a variation or additional to the original contract?
You respond by saying, OK, but how are we going to agree the basis for costing?
Typically, particularly if the request has come from the site manager, the normal response to this is
"Don't worry, I'll make sure you get paid: We'll sort it out at the end"
If you have any sense, you will respond by saying that prior to carrying out the works, you will need either a written variation or site instruction from the Project QS and you need to agree either a fixed cost or rates with the Project QS to cover these works.
Here's where all your problems start!
Now don't get me wrong, genuine QS's who fully intend to pay you for these works will like the paper trail that is offered by following the above process. However, QS's that either have no intention of paying, or pay at a rate/cost much lower than you have submitted, will not like this.
These QS's normally delay or totally avoid committing anything in writing and normally give the standard line:
"Proceed with the works, we'll sort it out at the end using fair and reasonable rates"
The problem for the sub-contractor is that this means he is carrying out works with no knowledge of how much, or if at all, he will get paid!
So you push it with the Project QS and say that you have supplied a fixed cost for these works (or rates), and that prior to commencing these works, you need written confirmation that these are acceptable (Clearly, you will be open to negotiation, but a cost or rates needs to be agreed).
You'd think that the Project QS would like this as he/she knows exactly how much these works will cost and it should help with monthly forecasts and you'd be right (If the Project QS had any intention of either paying you, or paying you at the cost/rates you had submitted).
So you hold out and insist of written confirmation and agreement of basis for costing.
At this point the Project QS normally tries to force you into commencing the works by threatening you with the following contractual clause:
'If the sub-contractor fails to proceed diligently or complete the works within the period specified or agreed, he shall reimburse the Principal Contractor for any loss, damage and expense suffered or incurred by the Principal Contractor'
This 'bullying' tactic is further driven home by the Project QS telling you that if you do not commence with the works, they will bring in another sub-contractor to carry out these works and counter charge you.
I know at this point, decent QS's are thinking
"This doesn't happen, I never do that!"
The reality for sub-contractors, is that this is something they face every single day when working for Principal Contractors. This is the 'real world'.
It's a bit like taking a new car from the dealership and telling the salesperson, you'll keep the car and then at some point tell them how much you're prepared to pay for the car, or if you are willing to pay for it at all!
Ridiculous I know.
Welcome to life as a commercial sub-contractor!!!!!