Hi All,First off, thanks for the assistance offered on my last query. I at least now have a better understanding of the problem, even if my first 'fix' wasn't the one.Problem: When I drain water from the basin, the water pushes the air ahead of it in to, and then out of the shower trap. I've seen it bubble up and over, gurgle and then release lovely lovely smells.T off to shower drain - Red = flow directionAlthough the drain itself acts as a bottle trap, from the T piece there's no real drop at all - I can see that pipe being a big volume of air to be forced back in to the trap. Should there be a P trap/downward angle on that T piece? I can imagine that the head of water pushing the air ahead of it would happily rise up that branch.Steps completed so far Before I really understood the problem, an air admittance valve was suggested in after the trap under the basin. I've now installed once of these, and am confident that this isn't the cause of the smells. None the less, here's a before and after of the trap. (I've got more of my cupboard anyway!)Sink Trap BeforeSink Trap AfterPotential SolutionsA shallow trap installed between shower train and tee, like this: https://ift.tt/3nF9cdg self sealing membrane trap installed between shower train and tee like this: https://ift.tt/36WWr82 are /r/DIY's thoughts on these solutions? Do you have another, more correct proposal? via /r/DIY https://ift.tt/2SNLbTa
