Kitchen waste backflow into bath

[noelrobx]

I'm trying to help a woman in my flats who has kitchen waste coming up into her bath. I have cleaned out the pipework from the bath to the stack but cannot get any further into the stack as there is an obstruction (or is this normal?). The kitchen waste joins the bath waste about 12 inches before the stack. The pipework is all horizontal...is this causing the backflow?

Please...any help would really be appreciated (after 5 hours work I am very frustrated!)

Cheers, Noel

 

[TicklyT]

There shouldn't be any obstruction where the waste pipe enters the stack, that could well be the root cause of the problem. Without a clear run to the soil stack, the waste from the kitchen sink will take the next available route - in this case back up into the bath.

There should be a slight fall to the waste pipes, something of the order of 40mm per Metre is usual. Some are installed with shallower falls, but plastic pipes can sag over time, allowing water to pool in the pipe, and blockages to form.

IMO teeing waste pipes together is not ideal. It's better to have each run seperately to the stack. Another contribution to the problem you have.

Some may suggest adding a HepVO trap to the bath waste, but that only addresses the symptom, not the problem.

 

[noelrobx]

Thanks TicklyT.

So, there should be about 80mm fall over the 2 metres of the length of the bath waste pipe? Well, it looks completely flat to me so no drop at all.

Could there be a bend where the bath waste joins the stack so making a blockage? The blockage is quite solid, it doesn't feel like something stuck in the pipe, more like the pipe itself.

Trouble is it's in an awkward position for me to do anything.

Noel

 

[TicklyT]

Sometimes waste pipes do turn and drop vertically before they enter the side of a stack. There's always a rodding access point where they turn.
Did I say always? Well, I meant sometimes.
Sometimes? Actually, hardly ever.

You might be able to persuade a flexible drain cleaning 'snake' round the bends.

Being conscious of the potential damage to the environment, I could never condone using caustic soda to try and shift such a blockage.....