Flushing Toilet in main bathroom backs up shower tray in ensuite room...

[kofi2003uk]

hi Everyone,
i have this problem and hoping someone can advice me please. UK property built in 1999 4 bed with x2 ensuite bedrooms. when the toilet in main bathroom is flushed, the ensuite shower in second room backs up. the drain in this shower has always been slow but works.

the main bathroom is not used a lot, as we mainly use the ensuites but recently have visitors so main bathroom being used. am not sure if there is a link there but whenever the toilet in main bathroom is flushed, the shower in second bed ensuite backs up.

any ideas please on how to sort this out.

on another note i dont see an obvious vent for drains on this property. is this a requirement in UK properties please? this property was built in 1999. i was researching and apparently there should be a vent for the drains in the house but i cannot find any obvious vent outside or on roof. thank you

 

[Scally-Ho]

As you cannot see an external vent pipe, it will probably be inside an internal pipe casing and then be visible in the roof space with an air admittance valve at the top.
How long have you been in the property and has the drainage problem always existed, or become worse over time?

 

[kofi2003uk]

thank you for the response. i have lived here for 6 years now. the shower in this ensuite has always had a slow drain but i put that to the drain pipe under the shower not having enough slope but that is only my uneducated plumbing guess. all other bathrooms drain quickly.

the back up in this ensuite has happened before but nothing that had bothered me. very small amounts but todays has been a bit more so am thinking might be an issue as i cant also find a drain vent for this house. i havent seen one in the loft either unless hidden in a corner somewhere underneath all that insulation. thank you

 

[Scally-Ho]

Before you do anything else, buy yourself one of these and give the sluggish wastes a good blast pumping with one.
I have rental properties and every tenanted property has been supplied with one to great effect because they are used as and when needed. . . money well spent

https://www.screwfix.com/p/essentials-sink-bath-unblocker-125mm/13894

 

[kofi2003uk]

thank you v much, appreciate the response.

 

[Hugh Jaleak]

If the shower is backing up when a nearby WC is flushed then I'd wager you have a blockage somewhere.

Common issue with properties where an AAV has been used to cap a soil stack, and then the drain blocks, when a connected WC is flushed, the water is entering what is essentially a sealed tube, and needs to displace the equivalent volume of air. This air looks for the easiest way out, usually a shower.

Giving the wastes a good blast with something is never a bad idea but I'd also be lifting any inspection covers outside and see if there's any sign of an issue.

 

[kofi2003uk]

Thank you Hugh. Much appreciated.