Paul Wilson
In my opinion this is only going to camouflaging your problems. If I was installing new wet room flooring I would have removed all then install wet room forma which helps degree of run of water for drainage. The trap / drainage should be supported were a lot of standing / walking will happen. After all above a layer of plywood is laid to meet flush to forma. Once all secure the anti slip floor can be installed. Installer lays floor into shower trap then bolts top from trap to bottom this allowing water tight seal. Floor is laid down & swoops up walls for around 150mm. Regard Paul
