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hoze · Jan 18, 2010, 01:44 PM

I recently paid a plumber to install a shower and vanity in my bathroom. I kept the old bath. He attached the shower waste to the same pipe the bath waste uses.
Problem is, when we empty the bath water it comes up the shower waste and floods it, on it's way down the pipes to the outside. When I queried him the plumber said there's probably a blockage further down which isn't letting the water out quickly enough. But I would have to call someone else in, as he doesn't do that work. The pipe also has very little angle on it, almost none.
I don't think there is a blockage though. I have used draino and the shower and vanity water runs out fine. Commonsense and gravity tells me if a lot of water is leaving the bath and there is a pipe between the bath and exit, if the flow is strong enough it's going to have nowhere else to go but up this pipe (the shower). When the bath is almost empty, say 5cm left, the shower doesn't overflow. If I am right I think there are 2options:
1. Make the waste pipe a lot bigger.
2. Lift the shower up about a foot to allow for this bath water?
Are these options feasible?
Am I right in the first place?
Has my plumber made a serious mistake and if so should he be liable to fix it?
Any help would be appreciated, before I spend more money,
Leonie

ebaines · Jan 18, 2010, 02:08 PM

I think your reasoning is correct. The water isn't draining fast enough, so the water level in the shower and in the bath are both trying to reach equilibrium at the same height. Raising the shower would certainly help. One other thought - perhaps the waste vent is clogged, or is tied in to the drain line too far from the bathtub trap, which could cause the water to drain slower. Have you checked that? Did the plumber install a vent for the new shower drain? Finally, this may be a silly question, but here goes - are you sure that there isn't a reduction in pipe diameter somehere - like say there's a 2" diameter pipe from the bathtub that gets chked down to 1-1/2" at the new connectipon to the shower drain?

mygirlsdad77 · Jan 18, 2010, 04:56 PM

Did the system drain okay for a while after shower was installed, or did it never drain correctly after shower install?

hoze · Jan 18, 2010, 05:15 PM

No, it never drained properly when installed.
Also the pipes from the bath, vanity and new shower all drain into the one pipe that leads outside, therefore one vent. The bath is about 3 metres from this vent. Is that too far?

hoze · Jan 18, 2010, 05:18 PM

That is, there was no shower before. The bath and vanity always drained fine before the shower was put in. But since the shower, it has flooded every time the bath was filled up and drained.

mygirlsdad77 · Jan 18, 2010, 06:10 PM

Was this a licensed plumber that installed the shower drain? They may have been trying to make it as easy for them, and as cost effiecent for you as possible. However, it sounds like you need to hire a licensed plumber that can make this work correctly for you. What is the size of the pipe that is being used for all of these fixtures? Something just doenst seem right here. IF the system never drained correctly directly after shower was installed, then I would say(in a perfect world) that it is up to the shower drain installer to make this right. Good luck with this and please let us know how things work out.