Bathroom Vent Pipe

Bathroom Vent Pipe

1. Hi,

   Not a plumber so apologies if I get any technical bits wrong.

   Bought a house last year, it's about 10 years old and at the top of a very steep hill, at least weekly, but more often if the weather is bad we get a really nasty smell in one of our bathrooms (it's not me!).

   Doing a little online research it seems like the problem is that the waste pipes are venting into the bathroom (which I think is the highest point of the sewer). I don't believe the house has a soil vent pipe, at least I can't see it anywhere.

   What can I do?

   Many thanks.

2. hi
   i think you are right, there may be a problem with the system not venting to the atmosphere.
   checkout the outside of the house for a vent pipe, if not, try the roof space, it may have a air admittance valve,
   if it has an air admittance valve, that may be the problem..
   regards
   peter

3. Thanks Peter. There's definitely no pipe on the outside of the house, and I'm pretty sure there's nothing in the loft.

   The house is semi detached and our neighbors report the same problem, so I wonder if it's a problem with the design\ build rather than a failing component?

4. hi
   spot on again, i have seen some very poor soil systems installed.
   its not a big problem to solve.
   can you trace the route of the soil pipe from the upstairs wc, to the point it changes from horizontal to vertical?
   is it a bent or a tee?
   peter

5. Luckily I can trace the pipework very easily as under the bathroom is a utility area. Will report back tonight.

   Thanks for your help so far.

6. OK, here we go.

   My house is upside down, the kitchen and lounge are at the top, you then go downstairs to the smelly bathroom and some bedrooms, then downstairs again to the master bedroom and en-suite (not smelly), downstairs once more to a basement.

   The pipe run from the smelly bathroom goes:

   Horizontal large bore pipe under the bathroom. The toilet, sink, bath and shower tray join this, it ends with a T junction which goes almost immedately up to the kitchen in one direction and almost immediately down about 8ft into the basement in the other direction. The pipe then doubles back on itself horizontally to another T junction, continuing horizontally is where the en-suite bathroom waste joins the system, straight down is the soil waste pipe leading out of the house.

   I hadn't noticed until I did this that the bathroom is not the highest point of the waste system, it's actually the kitchen (dishwasher, sink and washing machine). The kitchen does not smell.

   I am 99% sure that we have no soil vent pipe either outside the house, or in the loft space, I don't think our neighbours do either and they also report the same smelly bathroom. It would be very difficult to add one (although not impossible, but probably very expensive as it would need to be about 5 stories tall 0- it's a weird house).

   Many thanks for any help.

7. Just fit anti-vac traps to your bath and basin as it sounds like your traps are being pulled dry allowing foul smells to enter.

8. OK thanks! How do I do that? Is it a plumber job, or should I be able to do it myself?

   I've always thought the smell was coming from the toilet - the water doens't look very "clean" sometimes when it smells in there. Is there something that I can fit to that too?

9. hi
   fitting anti vac traps to the appliances, may help stop the smell, its probably the easiest thing to try first.
   my only concern, is you say the the water seal in the pan is not 'clean'.
   and also your neighbour has the same problem.
   another cause for the problem to happen, is caused by 'compression'
   if there is a problem in the manhole, or around it, (ie no ventilation, partial blocked) and two properties are connected one wc flush can compress the foul gas into the internal pipe work.

   not sure if that makes sense?
   i may not have explained it well?
   regards
   peter

10. OK, I'll ask a local plumber to fit anti vac traps to the sink and bath.

    Is there anything I need to fit to the toilet?

    Peter, thanks for your continued input - if I do the anti vac traps and there's no improvement, I then look at the manhole. Is that a good plan?

11. hi
    if you are getting a plumber in, it my be best to let him actually look at the system first, he may see something that has been missed here.
    regards
    peter
    ps not being able to see the problem first hand is not good place to start!
    i have other ideas if the problem continues

12. What are your other ideas? I'll start a list of things to try!

13. As Peter said earlier if you have dirty water appearing in the toilet anti-vacs won't help,best to get the plumber to have a good look at the system layout and go from there.

14. hi
    may sound odd but how about looking at your pan, while other appliance are emptying, bath sink etc,
    and not forgetting next doors wc flushed! you may see some movement?

    regards
    peter

15. If you have bought your house and its only 10 years old you should have no trouble getting the building plans from your local council. These should show any (or not) vent points on your soil system.
    Many years ago ( I like a story), I had to get the plans for our old victorian house. The soil had blocked up and we couldn't find a manhole. Our house was the last one built on this particular hill. Years later more were built next to it going further up the hill. After securing the plans we found that there was no manhole but a trap was fitted two feet under the bay window wall in the basement. After a bit of digging (bottom of the outside basement steps) we found the trap, capped with slate tiles. you can imagine what happened next. One poke and a hole full of s##t.

16. Checked the sink last night, already appears to have an anti vac trap fitted (has that little valve bit sticking out).

    Will watch the toilet while everything else is emptying and see what happens.

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Bathroom Vent Pipe

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