Bath Waste coming out of shower

[Alfie25]

My bathroom has a separate shower and bath - each on a different side of the room. When I drained the bath last night I heard a gurgling from the shower drainhole, then a couple of cupfulls of water came up out of the shower drainhole! I've lived here for 9 months and have never noticed it before.

From what I can see from looking under the bath it appears that the pipework from the shower waste joins into the pipe for the bath waste which then goes the short distance to the internal vertical soil stack in the corner of the room (beside the bath). The shower is furthest away from the internal soil stack, so it seems the bath water is backflowing in the opposite direction towards the shower, across the entire width of the room. Unfortunately the floor is tiled so it's not a case of just lifting the floorboards to check the pipework in any detail. The basin waste may also be tee'd into this arrangement, but it's impossible to see.

I suppose I have a few questions:

Could something have happenned to cause this backflow all of a sudden or is it more likely to be poor installation in the first place? I was thinking maybe a blockage and trying some cleaner sown the pipes - or could this do more harm than good?

Other than being an annoyance, is this going to cause any other problems?

 

[longdogs]

Yes sounds like a blockage (probably hair and soap) in the bath waste pipe and it's probably at the point where it meets the stack pipe. When the shower tray was installed it should have had a seperate waste pipe or at least an inline non-return valve on the shower waste.

You could try a waste unblocker but make sure you stick to the instructions as some of them can be pretty powerful and can melt your pipework. Is it possible to remove the bath trap and rod the pipe with an auger?

Failing that, you could get a drain specialist in which might be expensive but would save lifting any tiles.