Soil stacks?

Nov 02, 2013 6 Replies

Horrible 'drain' smell in a en suite bathroom. Family bathroom & downstairs (below) cloak (unaffected) have boxing in the corners obviously containing the soil pipe, confirmed by being able to see the soil pipe vent on the roof.



No vent visible anywhere else. En suite is 20' away from family bathroom on a different side of the house.



Is it possible to have a soil pipe with no visible vent?



On Saturday 02 November 2013 15:52 The Medway Handyman wrote in uk.d-i-y:

Hi Dave,

Yes - it might have an air admittance valve (AAV) like this:

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usually near the loo in the boxed in bit.

Those can sometimes need replacing due to hardened/stuck flap valve.

Another possibility - are there any U-Traps on showers/wahsing machine drains/etc that are empty of water due to lack of use?

It might also be that no one fitted any type of soil pipe vent, even when there should be one.

Also, a vent pipe doesn't have to be full size of the soil pipe. I can't remember what the minimum allowed is (it's specified as some ratio of the size of the soil pipe), but ISTR working out that a 68mm gutter downpipe was allowed as a soil pipe vent.

Shower and bath u-traps are often very shallow, and easily sucked empty when there's a pressure differential (which is even more likely if there's no soil pipe vent).

+1 same problem in a bathroom cured by running the bath tap for a few seconds

Malcolm

Checked that, seems to be water in the shower trap.

That looks likely, trouble is, it's all boxed in & tiled.

No, checked that.

ce-valve-110mm-56712

At my daughter's last house, the kitchen gradually filled with the same sor t of stench. It turned out, as far as I could work out, that the sink drain pipe which ran into the stench had shifted further into the connection - t hey'd had work done a month or two prior. Adjusting the under sink trap and pulling the pipe back a half inch away from the stack did the trick.

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