Brandon is correct - this is huge. This is by far the hardest part of managing a mobile home park. Collecting rent from tenant owned home leases is easy and takes only a few hours per week, but construction is expensive, complicated, and time consuming.
Somebody gave the example that even WalMart will pay by the hour, however you are not WalMart. WalMart has supervisors and managers on staff 24 hours per day tracking what employees do and that their breaks do not exceed the minutes provided per the HR policies - there is no useless loitering. Unless you or your manager are able, willing, and competent to watch over the workers, you will have huge problems paying by the hour. It would not surprise me if you paid for 40 hours of work and all that was completed was a few cases of beer were consumed. By the time you drive 700 miles to conduct a site visit, you will think all is ok, but it is not.
We have had better luck drafting a contract with a defined scope of work and milestones for payments. If and when the work is completed, the workers get paid. The contract also has a work completion deadline, so if a worker sits around for 3 weeks, we can terminate the contract and hire somebody else without having to pay anything. Workers are independent contractors, so we are required to collect W9 and issue 1099 if we pay in excess of $600 per year. We typically pay for materials separately using the company’s trade accounts at the major retailers.