Ramprat

Thanks but unfortunately I don't think that would help the sink and bath drains both run to a separate foul water drain pipe which actually dumps out into an open drain by the kitchen (old raf house and the plumbing is a bit odd, along with most of the electrics? which is why we used "professionals" when we renovated it) so I'm positive its not these that are the issue, the toilet is the only thing connected to the main soil stack directly and into the sewer but what you've said has given me an idea, it could be the trap on the toilet that's being drained, ive never noticed it really low but maybe its low enough to allow the gas to escape? The plumber actually built that box after removing a taller one that was already there so if its too small that's his fault ?

That is the top of the soil pipe so no vent or anything. The smell comes from the toilet area, sometimes from behind the toilet near that pipe and some times the toilet itself (its clean ?). I can only assume from what you said about traps and from what ive read that because we have no air inlet or vent when we flush its causing a vacuum and then this is being filled with sewer gas that's finding its way out?

Hi Looking for some advice before the plumber comes next week its a bit long winded but please stick with it. 3 years ago he refitted our bathroom, about a year later we started getting intermittent cabbage smells in the bathroom but because myself and my partner do shift work we rarely noticed it or only one of us was at home and because it wasn't bad convinced ourselves it was either outside or in our heads as I'd checked everything I could access and it all looked ok. Last March some construction took place nearby and the smell became worse and more frequent but we were told by a plumber sent by the drainage company who unfortunately came on a day when it didn't smell that it was due to the workings going on and it would be completed soon. February this year the work was completed but by this time the smell was eye watering but again only at random times but id had enough and was planning to call the plumber back to have a look, unfortunately lockdown hit and my partner had to shield so we couldn't do anything about it, last month I was furloughed so I decided that as I had the time I'd research the problem and see if there was anything I could do even if it was temporary, I knew we didn't have a roof vent and i remembered the plumber saying something about a durgo valve in a box in the bathroom so I presumed that had failed and decided to take look, turns out the plumber had cemented the box closed and after serval hours of carefully taking the box apart I discovered that we don't appear to have an AAV at all, on speaking with the plumber whos saying he rembers the job well as it was a pain to do (never said that to me and charged enough anyway) he said that there wasn't a vent to start with and when he replaced everything he just did like for like and that because we are a terraced house we don't need one as we would be using our neighbours vent? Now for my questions, 1) is he talking bullshit about sharing our neighbours vent because we are a terraced house, I know the house at some point before we brought it a vent pipe as when we had the roof repaired they found the old pipe cut off and covered with mdf so it was removed it. 2) would any skilled plumber replace like for like even if it was the wrong thing to do? and what do the building regs say about this set up? 3) how much would i be looking at cost wise to fix this mess roughly, I think i know what parts we'd need and guessing non trade price is around £60 and I'm guessing a couple hours labour so am I right in thinking £150ish max I'm hoping he will sort it and fit the AAV for free but im just planning for the worst as its been 3 years im excepting the old "it worked fine when I finished its a new issue story" I've attached pictures in case im totally wrong and missing something but to my amateur eyes it doesn't look right, even the pipes don't look sealed correctly. Please help so I have the correct information and confidence to be able to deal with this when he comes next week, im already unwell due to a fair up of a chronic illness and I could do without the stress of fighting this or the cost of fixing it as like many others im sure im also at risk of redundancy so im trying to save what I can in case the worst happens. Finally if all else fails how difficult a job would this be to attempt myself, im an ok DIYer I've never done any plumbing but I've learned electrics and wood work and willing to try or is this one I should leave to the experts.