Factor.

Your merchant needs to understand the ins and outs of factoring before he is pushy and says "No! I don't want anyone calling my clients!" - it's more professional than that. If you're a construction company or contractor and you say "No" to factoring even though it's the perfect solution, than something is wrong.

No matter the credit- construction is high risk because of... Everything. There is no gaurantee of payment unless the job is complete- what if they can't complete it or something happens while doing it?

If they want to take their personal financials or assets into play he can get a LOC and have a monthly interest off of that.