From your description, the solution seems obvious. The factory needs to come to the building site, rather than the other way around. So the opportunity essentia

From your description, the solution seems obvious. The factory needs to come to the building site, rather than the other way around. So the opportunity essentially becomes one of providing better tools to builders. This has already happened in some ways since air nailers are a nice productivity gain over hammers and have taken over. If you could deliver automated tools that could fit on a tractor trailer, say a robotic arm/crane with a few attachments, you might have a winner.