unskilled workers are sharing the responsibility with project managers:) i m into this business and they really suck and u shud always have an engineer with them to even measure correctly the pipes etc. and probably (i havent yet) but guys who have responsibility will be damn bored and crazy and let them go. and yes even u r trying to make luxury places u will have those stupid problems. cuz engineers cant control everything. a normal guy shud understand that there is a problem in that door:)