The customer came to us after we completed a family members bathroom, they had a number of plumbers in prior to us to find the leak/fault that was coming and going, which did not make sense. So on the first meeting, I came to the conclusion that it only happened when the older children were using the shower for longer time periods i.e. pipework was filling up then leaking, so in order to see this we had to rip everything. Our suspicion was right, it was a screw from the previous bathroom fitter screwing the floor-boards down, so it would only leak when the pipe filled up and had to work its way through layers of ceramic, floor insulation and plasterboard so was not obvious to customer straightaway. After finding this fault we replaced there complete bathroom suite through the customers insurance.