Metric Tensor wrote: » The best practice is to have the soil vent completely outside of the building but many people hate that because it looks .... less than pretty! Failing that the stack should go up through the roof (not into that attic). I've never seen one penetrate horizontally through a wall! I don't know what the exact "rules" are in this regard but what you have described is definitely far from ideal. I take it that it's not your own house to change? Edited to add: Despite all of the above if you have a smell of sewage in your bedroom I'm not convinced it's the location of the top of the stack that's causing it. Leaks or breaks further down in this pipe or others may be to blame.
kceire wrote: » Have a look at the section of Technical Guidance Document Part H that deals with. Ranch connections and vent pipes. I wouldn't be too happy with your arrangement and I would insist on the pipe to continue out through the wall and vent above the facia/soffit. But as MT says, there may be leaks or cracks or loose connections in the flexor housing that feeds the existing wall vent.