Soil pipe in flats

[parklands]

Hi, Is there a recommended soil pipe diameter for multi-storey properties? I live in a 5 storey block which has a stack with an AAV fitted. There are regular problems with syphoning and the AAV has been replaced. I was wondering if the pipe is of sufficient size for a run of this height? Are there any other options than durgo valves?

 

[Meady]

You can get anti syphon traps, nothi to do with the size of the soil pipe

 

[parklands]

To fit anti syphon traps on all bathroom outlets would require a complete rebuild of the bathroom as all fittings are behind tiled walls. Even the level in the toilet goes down by 2 inches when the penthouse toilet is flushed. Everything works fine when the AAV is missing - apart from sewer smells!!

 

[SimonG]

Is the air admittance valve boxed in? and if so does the boxing have a vent. If its sealed inside a boxing it wont admit a lot of air.

 

[parklands]

Thanks for replying. The AAV is in a storage utility cupboard and has reasonable space for air circulation but it's worth a thought.

 

[snowhead]

Where abouts is the AAV fitted, Top floor flat ?

110mm should be good for 5 flats with an open, to outside, vent at the top.

 

[parklands]

Yes, ceiling height in top floor flat. Single 110 pipe serving 5 bathrooms over 5 floors.

 

[stevetheplumber]

if its at ceiling hieght in the top flat how hard would it be to take it through the roof or wall to atmosphere?

 

[AWheating]

should really have been vented to outside imo.

 

[parklands]

I'm no expert but I agree, that is the best solution but obviously been done at the cheapest cost. Getting it changed would not be cheap - £2,000 for scaffolding before you start. Don't think the residents would be prepared to find the money. You have all confirmed my view so thanks very much. I could do with an expert to say it is a design fault and enable a claim on the NHBC insurance.