We have a Dethleffs T6611 and back end of last year we noticed that around the not used outlet in the shower tray that the plastic seemed soft as if there was nothing underneath it. So this spring I decided to remove the interior of the shower room and toilet and lift the shower tray out and have a look as if I did not I was worried a hole may appear in the tray. What I found astonished me as I allways thought of the Dethleffs as a well built motorhome, under the second not used out let was a 6" hole with just a very thin piece of aluminum over it which allowed the base of the shower tray to flex badly, not what you would expect from an expensive M/H. I took out the tray and the false floor filled the hole in the floor with a plywood disk on top of a floor bearer which I fitted as Dethleffs had cut away the original. I covered the underneath of the tray with two layers of fibreglass, and when dry, sanded to a flat finish, cut a hole through the new fibreglass for the outlet. I then replaced the floor the shower tray, the toilet and all cupboards and towel rails etc and made a new teak grating for the shower. In all this took 3 days to do, all because the factory left a big hole where there was not one needed and then tried to cover up with a very thin piece of aluminum. I have attached pics.