In reply to Dave B:
That depends on the company, some charge to put up and dismantle plus a weekly hire rate, other just charge for putting up and taking down again, their build costs tend to be higher but with no rental it can work out well over longer periods.
One thing to remember, a scaffold needs a inspection once a week if its used for commercial purposes. I know its domestic for the OP but if he is employing a builder then it becomes commercial