Shower Pipework advice needed please

[Edward_B]

Hi All

I found this forum quite by chance this afternoon whilst looking for an answer to a plumbing question that I have following a rebuild of an annexe at our house.

The annexe has a small ensuite containing a shower, washand basin and WC.

The builder completed the work just prior to Christmas and everything seemed fine. However... the ensuite has been used for a guest in January and we have found that, everytime the toilet is flushed, the shower waste overflows in to the shower floor area brining with it the effluent from the WC.

The smell is horrendous and we are desperate to get the issue fixed properly.

When the ensuite was built in November, the shower floor was raised by about 3 inches to provide a drop for the waste water to flow in to the waste pipe which was connected to the WC waste. The pipework then flows out to the underground waste pipe.

All of the pipework has been boxed in and tiled.

I am really not sure how best to proceed. The builder is a friend of mine and he arranged for various people to be subcontracted in to complete the work required.

Can anyone advise me what should have been done initially to stop this back flow occurring keeping in mind that all of the internal pipework from the show, WC and wash hand basin lead to one outflow pipe in the floor of the ensuite.

I have done a little research and one possible solution is to fit a non-return style flap / valve between the shower outflow pipe and the union where it joins the WC outflow but I'm really not sure if this will work affectively.

Can anyone spare a few minutes to offer me some advice please ?

Regards

Ed

 

[Ben-gee]

A non return valve should not be necessary if the pipework is done correctly.

Does the shower join into a branch directly behind and in line with the wc?

Or is there a blockage further down the waste pipe so that the waste is not getting away in a timely fashion? Try lifting the manhole and see if it’s clear.

 

[Edward_B]

A non return valve should not be necessary if the pipework is done correctly.

Does the shower join into a branch directly behind and in line with the wc?

Or is there a blockage further down the waste pipe so that the waste is not getting away in a timely fashion? Try lifting the manhole and see if it’s clear.

 

[Edward_B]

Hi Ben-gee. To begin with, thank you so much for getting back to me so quickly. Yes, I think you are absolutely right. I hadn't thought about a blockage in the pipework outside of the house and will check that first thing tomorrow morning. I took some photos when the pipework was under construction and have attached them to illustrate how the pipework is. There is a drop in levels between the shower trap and the point where the builder has joined it in to the waste pipework at the rear of the WC. The builder tested the drop before boxing in the pipework and water certainly flowed away. I honestly can't remember whether the builder tested the WC though. Hope the photos help. Do let me know what you think if you get a few minutes and, once again, thanks so much for your advice. All the best, Ed

 

[Ben-gee]

That’s not a good way of doing it unfortunately, would have been better to take the 1 1/2” to the corner of the room and connect it under the floor to the vertical bit of the soil pipe.
If this is no longer possible, then a non-return valve in the 1 1/2” is your best bet. Leave access to this by way of a panel if I were you….

 

[Edward_B]

That’s not a good way of doing it unfortunately, would have been better to take the 1 1/2” to the corner of the room and connect it under the floor to the vertical bit of the soil pipe.
If this is no longer possible, then a non-return valve in the 1 1/2” is your best bet. Leave access to this by way of a panel if I were you….

Morning Ben-gee Again, many thanks for getting back to us. Yes, I can see what you are saying and think you are right. We also have a feed from the wash hand basin that goes in to the waste and also a condensate pipe from the central heating boiler. Unfortunately, these were boxed in by the builder before I could examine them. I suspect the only way forward to resolve this issue properly is to place the entire job in to the hands of a reputable local plumber and see his / her advice. I'll post the solution once everything has been sorted out. It's just such a pity as the whole boxed area and tiles will be lost but, at least the job will be fit-for-purpose rather than a disaster waiting to happen. Thanks for confirming my suspicions. It's made all the more difficult for us as the builder who managed the project is a personal friend ! All the best for the future, Ed