I purchased a new property and have had a slow draining shower since day 1. By the end of a shower I am always stood in an inch or two of water. I have also noticed that when the sink tap is running on full there is lots of gurgling and water will appear up the plughole of the shower. I purchased plenty of drain unblockers but nothing worked so eventually I got a plumber in. He took one look and said the fall of the waste pipe was not steep enough. It was flat along the floor, absolutely no fall at all. Had him in yesterday to do repairs and this morning when I tested it there was no difference at all. Water still filled the tray and water from the sink still came up the plughole.
If it is not due to the fall of the pipe and drain unblockers are not doing anything what could be the problem here??