Background explanation of plumbing layout: my bathroom is directly above my kitchen, the soil stack for the bathroom runs through a boxed in compartment in the kitchen, the bathroom sink and the bath drain into the soil stack (I think). The bathroom is nicely tiled and I have no access to the sink/bath wastes. Problem: From the kitchen when the toilet is flushed there is no excessive noise from the soil stack or above the ceiling, however when you drain the bathroom sink or run the sink taps it sounds like water is being poured onto a flat surface or maybe like water falling into a shallow pool just below where the sink is. Draining the bath makes no such noise. Question:I *think* that the sink waste must have an odd elbow or something on it which is causing the water to tumble down vertically then hit the (near) horizontal run which is causing this splashing noise. I am having the kitchen ceiling re-plastered soon so now is a great time to open it up and have a look... the question is how should the waste be arranged, a nice shallow angle all the way to the stack, as few elbows as possible?
All advice appreciated!
GMC