A soil pipe which drains two bathrooms and a kitchen from an upstairs appartment runs into my kitchen and empties into the main (under my kitchen) drain and thence to the sewer. Intermittently over the last two years it given off a bad smell. I got a drain contractor to check for blockages and it was completely clear (both main drain and the soil pipe). He suggested that the most likely problem was a crack in the soil pipe where it changes course from vertical to horizontal (cctv work was done but no large cracks were immediately obvious). We therefore lined the inside of the soil pipe to plug any cracks. However, the smell has reappeared and is no better. It is worst in the mornings and evenings and appears to be almost exactly correlated to toilet use in the upstairs flat. It even seems to smell of clothes washing when the washing machine is being used upstairs. I can't work out how a smell could be getting through as the whole system should be sealed (the hatch has even had silicon applied to the edges. There is no smell in the upstairs appartment. Does anyone have any ideas - could it be a problem with venting? But how does the smell get out and why would it appear so quickly after toilet use on some occasions and not at all at other times?
Please help.
Thanks
John
Please help.
Thanks
John