toilet problems

[novice67]

Hi guys

I have just moved into a top floor flat that is 9 years old. I have a main bathroom and on an adjacent wall an en suite. When you flush either toilet some of the waste and water appears in the other but not every time. I had someone out who raised one of the toilets but that did nothing. What is causing this and what can I do?

 

[novice67]

Thanks for the two relies have now registered to get some more help, do I need to get a plumber and will it involve taking the tiles off to get behind to the pipes. Sorry but am a female alone and have no clue and don't want to get ripped off thanks.

 

[joni os]

With cases like this redecoration is often more costly than the plumbing. A simple solution is to use "blue block" in each cistern. It won't stop cross flow but will make it less noticeable.
In a similar situation, hotel back to back toilet from adjacent rooms. Guest was not best pleased at thought someone had used his facilities. Ripping out pipework would have been costly and inconvenient. In that situation cross branch was end of run with rodding eye.
It was possible to access and place purpose made diverter, Hot moulded from 110 mm soil pipe. Many plumbers will be reluctant to adapt fittings.

 

[Phil]

Why did the plumber who raised the toilet not just use the £20 mcalpine backflow devices on each toilet. Job done.

 

[Eric withy]

Beat me to it macalpine back flow devices

 

[JCplumb]

A simple solution is to use "blue block" in each cistern.

Really?
A plumber recommending blue loo blocks. Well I hope this job is in your area and you have to change the syphons on those loos when they go.
I thoroughly detest the blue loo things, not keen on having smurf hands for days after coming into contact with them either

**Disclaimer** Although it's not actually a bad idea for a simple workaround to the problem.