The soil drain vent pipe runs up to the roof in the corner of our back bedroom and is connected to the toilet through the dividing wall. Recently, we've noticed a sewage smell in the bedroom when the powerful bathroom fan is on.
I un-boxed the vent pipe and removed it from the connecting pipe/boss. Peering down, I noticed that the plastic pipe does not appear to sit properly into the female socket of the clay pipe bend located in the soil below the concrete floor (see drawing).
[url]http://www3.snapfish.co.uk/slideshow/AlbumID=281831412/PictureID=6744122587/a=136644902_136644902/t_=136644902[/url]
The lower section of the access fitting is firmly cemented into the floor. To move it at all I would need to break up the cement, but only at the expense of making a load of dust and possibly breaking the fitting.
If I could possibly sleeve the fitting from the toilet branch and down into the terracotta bend, that might reduce and seepage to an acceptable minimum. I know professional drainage companies use expanding sleeves that cure into a watertight seal, but can a DIYer buy those and fit them? Though not an easy job, the offending joint is within an arm's reach, so it should be possible to do it manually.