I hope that you'll do well in your new venture but, and no offence intended, I smiled a bit when you mentioned that your contacts in the building industry aren't happy with their cleaners. I know (or at least I think I know) why.
On another thread on this site, someone is looking for help to complete a quote for a builders clean. Specs have been listed and I think that they'll get the help they need to complete the quote - this is very much a friendly site but there is nothing in the nature of the query to suggest that the poster has the first idea about what they're doing.
So, they'll get price guides, reduce given margins to "get the job" and eliminate the professional companies also bidding for the work and there's a high chance that they'll get it on cost. They will then struggle with cash flow, material and equipment supply, training (toolbox and otherwise), CIS processing, insurance and, naturally, operating standards. They'll do better than I think if they break even on the whole job. The surveyor or project manager or site manager, on the other hand, will be astonished yet again to discover that the cheapest quote given wasn't from a company able to carry out the required tasks to any measurable degree of competence. It's true of the the industry generally, but builders cleans in particular, that there's much, much more to cleaning than cleaning.
And that's why I'd recommend caution with your contacts - they're not happy because they fondly imagine that cleaners (the lowest paid people on any building site) should be working for nothing and that pixie dust is an ideal replacement for 240v power and a water supply. The question which I'd be looking for an answer now, in your position, is whether they'd be prepared to pay you personally more for the service they're getting than their current contractors - if they claim that they are, that invites the question as to why they didn't do that in the first place. If they had, they wouldn't be unhappy.
