Rhinoman is spot on,
60% of my work is now builders cleans but in the major refurb sector, will never consider working for house builders, I implemented an SLA two years ago with the countries two major pub tenancy companies working alongside three of the construction companies that cover the whole country for them, have never been asked for a price before we start and have never been queried on invoice, we offer two types of clean, we can make it look like the builders were not there, (basic builders clean) or a turn key operation where we will sparkle it up to the eyeballs to the point where they could just open & trade, we do a great deal of night work on these properties and have an 18 hour window from practical sign off by the designer and client, then work with and around the construction company while snagging is completed for final sign off, that way never any call backs, builders cleans can be a nightmare, build a good relationship with the construction company and work together they are a doddle.
Average builders clean for me, 300K refurb, 36 hours on site, add on's such as floor sealing, power wash to car park, clean out gutters, 2K, then I will speak to the new or existing tenant and leave them a floor maintenance guide with a bit of free stuff, advise them on the kitchen duct work legislation and do them a free Fire Risk Asessment to highlight any immediate concerns, we then have this customer direct for all kitchen work in the future.
Its about delivering a product that pleases the designer, property manager from whichever brewery and then nailing the tenant, patience, perseverance and making them see the value of your work.