hi there
the expansion question is always very difficult to sort !!
the question to ask are ??
am i working all the time on site, and therefore missing other potential work ?
is there enough additional work if you spent say 50% of the week, off the tools, to give another van work for a week?
at the moment you enjoy an economy of scale, ie 1 man, 1 van, overheads etc, add 2 man, and 2nd van, the overheads remain the same, apart from the man and van cost, therefore at day one of the expansion plan, you have a dip on th p and l graph, until you are both working at say 75% again.
its always easier to expand from 2 to 3 vans, and 3 to vans etc, its the first 1 van to 2 van which seems to deliver the most pain.
at the end of the day its only you who can make the decision as to which way you want your business to go and where you want it to be in say 2 years and 5 years time.
whatever you decide good luck
regards
martin