Smells in downstairs Wc

[Greeno80]

Hi,

Hoping someone can help.

I have just bought a house, moved in, and it stinks! The smell comes from the downstairs wc. The wc had a toilet a basin, a carpet floor and an extract vent.

The house was built in 1989 and has an internal soil pipe which terminates in the loft with an AAV.

I have bought a new toilet and basin and got three quotes to replace them, two of the plumbers reckoned that changing thm wouldn't solve the smell and said I should try and sort that first, saying it might be the carpet, extract fan or AAV.

I have removed the carpet and underlay, smell is still there. I have cling filmed over the extract, smell is still there. I have replaced the AAV, the smell seemed to be going but now is back.

I have checked my drains, there are three toilets in the house. I put blue toilet paper in one, pink in another and white in the third and got the wife to flush them one by one. I stood by the outside inspection point and all three coloured papers came through so there can't be any blockages.

The smell is similar to the svp when I take the aav off, so i'm pretty sure it is gasses from the svp. There are also some pretty funky noises from the svp when I flush the en suite toilet.

Has anyone got any ideas how I get the smell out of my house?

 

[Nige F]

get rid of the AAV - take the pipe through the roof Probably easy for me to say as a plumber , but they are the devil`s work It might also be a urine soaked floor under the carpet - or smells coming up through a handbasin trap ( assuming there is one in with the WC)

 

[Hugh Jaleak]

With Nige there. AAV's have their place, but wont allow any positive pressure to escape from the drain. It then looks for the path of least resistance to escape, possibly the basin trap.....

Leave manhole cover open a touch, (not so much as anything can fall down but enough to ventilate the drain), and see if that helps.

 

[Greeno80]

Thanks guys,

The floor is old thermoplastic tiles and is as dry as a bone, so don't think it's urine. The smell comes and goes too, I deffo think it is gases from svp.

Is taking the aav off in the loft a good idea? Just for a few days. If the smell goes downstairs then I know I have to put the svp through th roof. If it doesn't then I know I need to look elsewhere?

How much roughly do you think it would cost me to get someone out to take it through the roof and flash properly? I don't think I would trust myself to get it right. The svp is right under a purlin so it would adapting before going through the tiles.

I'm thinking of putting a smoke bomb down the svp too, find out if air is coming from the basin trap. Is this an ok idea or might I cause more problems.

Cheers

 

[Hugh Jaleak]

Removing the AAV might prove a point, wouldnt want to spend too long in the loft though! Not much of an issue to alter the dry (vent) section of the pipework, can put as many bends as you like in there.

Smoke bomb, i'd be careful. Smoke will escape from anywhere it can, with the AAV on then i'm not sure how it would disperse, removing AAV could fill loft with smoke! Air test on drain/stack should indicate if there are any leaks, problem would then be finding it!

 

[spraggo]

You may be aware that the AAV is a device that normally seals the top of the soil pipe from the atmosphere. However, when you flush the toilet a vacuum is created within the soil pipe and the resulting suction causes the AAV to open and let air in to release the suction. If the AAV is faulty by failing to open, the vacuum remains in the soil pipe and cause water in the basin waste trap to be sucked out allowing the smell from the soil pipe to escape thro the basin trap. Hope this helps.

 

[Greeno80]

Thanks spraggo,

The aav is brand new though, purchased from wickes only a few days ago. I've checked it and it doesn't look like it sticking. Are there different types or air flows? Have I got the wrong type? Have I fitted it incorrectly? It was push fit so went on well and looks fine.

The basin is full of water with a plug in and the overflow is duct taped so even if the trap is empty I don't think the smells would come though, would they?

The annoying thing about this is not knowing what the problem is!

 

[Hugh Jaleak]

An AAV is an AAV AFAIK. If there is positive pressure in the drain it will probably 'bubble' out, not enough to be noticed by sight but enough to be smelt.... Have you checked the soil pipe? Not unknown for a boss adaptor to be displaced or an an abandoned connection not to be sealed off....

 

[Greeno80]

The soil pipe is completely concealed through the house, it's behind a kitchen cupboard and is boxed in by plasterboard even if I remove the cupboard. I have taken off the plinth to the kitchen units but it is even plasterboard boxed down to the floor. Upstairs the pipe is fully concealed by ceramic tiles in the bathroom.

I am a compete plumbing novice though, so apologies for the stupid question but is a boss adaptor the thing that connects my downstairs toilet to the Svp? Is it possible that air is leaking out of that joint, so if I do replace the wc, and use a new boss adapter, it might be problem solved?

 

[Hugh Jaleak]

Pan Connector is used to join the spigot from the back of the pan to the soil pipe. Unlikely to be leaking unless it has been disturbed. Boss adaptor is a rubber part that fits inside a boss to join a waste pipe (either 32, 40 or 50mm) to the 110mm soil pipe.

Strap boss: http://www.screwfix.com/p/soil-strap-boss-sp319/49547
Boss adaptor: http://www.screwfix.com/p/floplast-boss-adaptor-40mm-pack-of-5/89174

It does seem more likely though if stack is 'sealed in' the smell is venting via a trap. Should the leak be at the stack then I would have thought it would vent upwards into loft space anyway, rather than into the room. Try putting some cling film over the WC pan (Advise household the WC is not to be used first!), and see if that makes any difference.

 

[Greeno80]

Right guys, I have finally figured out where the smell is coming from....thank god.....it is from the waste pipe to the basin.

The waste pipe is 35mm thick, it is connected to the basin trap, and then drops through a concrete floor into a vertical drain (looks to be 110mm thick). There is nothing connecting the two pipes. The basin waste literally just hangs.

The junction of the concrete floor and waste looks like it was historically sealed, so no smell would have come through, but over time the air tightness has gone, and the edges of the concrete have crumbled slightly so the smell from the sewer is coming straight up the 110mm pipe, through the poor detail around the 35mm pipe and is making my house stink!

Is the detail described typical of a plumbing installation in a 1989 house build or should there really be something connecting the two pipes together?

Should I just put the 35mm pipe back in and seal the holed floor as best I can or break out the floor a little, join the pipes properly and then re screed the floor?

Cheers

 

[Madrab]

There really should be something connecting the pipes IMO. Get a 110mm to 32mm reducer for the top of the drain pipe and fit the waste to that. Then make good on the floor

 

[Hugh Jaleak]

Should be a proper joint there, especially in a property of that vintage! I'd do the job properly, and seal it in. Assuming you've a 110mm plastic pipe under there, i'd remove enough screed to get one of these in: http://www.screwfix.com/p/universal-waste-adaptor/51416

The adaptor fits inside the 110mm pipe, simply cut as required to accept the waste, (make sure its a snug fit over the waste), then make good the floor, ensuring you dont disturb the connection.

 

[Greeno80]

Thanks guys....and Hugh especially..thanks for all posts, much appreciated!