Methane smell in newly refurb bathroom, piglet John??

[looby11]

My heart feels broken. We waited patiently 5 long years to do up a horrible 70s bathroom and although it looks stunning now as it’s all finished I can’t bear to go in as there is an overwhelming stench of sewer and methane. After the first day of work ( first fix) we noticed this smell but they said they hadn’t covered the pipes up and left us with that smell over the weekend. They mentioned p traps and it all made sense. Anyway they covered the exposed pipes and the smell was not noticeable so far so good. Now they have just completed and the builder handed us the bill yesterday. However all day today the smell has been overbearing and I’m so sad. They said once water was added to the toilets and shower it would stop the smell but it’s not seemed to work. Everything has been caulked up and there are no “gaps” other than the fan inlet.

What is our position ? What do we do. Please tell me it’s easily remedied and doesn’t involve ripping up the newly tiled floor?
The plumber did access under the floor via another room to check.

Also extra info so as not to drop feed is that the toilet position was changed and a bidet removed. And we can’t we can’t see where the waste pipe for the bathroom opens out to. So there is def no p trap that goes up out towards the roof.

Sorry if It’s long and rambling and a bit comfusing

One of our bathrooms upstairs stank for a few days in the very hot weather. Seems to have sorted itself out.
Our plumber reckoned a seak may have expanded in the got weather and now gone back to normal.
Dont know if that's true or feasible but it doesnt smell anymore

What paint has been used?

And we can’t we can’t see where the waste pipe for the bathroom opens out to. So there is def no p trap that goes up out towards the roof.

OP, do you mean you can't see where the soil stack is? Where was it before they moved the loo? Is it a downstairs bathroom?

Have you paid the builder? If not I wouldn't pay until he's sorted this out. I don't think it's paint as you say you could smell it from the first day of work.

I expect Piglet will be able to help, but maybe post some pics as that might throw light on the issue.

OP, you need to @ Piglet’s username to get him on this thread.

Where did the soil pipe go before the changes? Usually it goes past the bathroom, and, at a higher point than any of the house windows, is open at the top to vent any pressure or smells.

In older houses the soil pipe will be on the outside of the house, in newer ones it is in a duct in the corner of the bathroom, and of the kitchen which is usually below.

A poor alternative us to fit a nominally one-way valve such as a Durgo, and hide it behind boxing in. You'd be surprised how often they fail. Even worse is to have no vent.

Ask around for personal recommendations, from people you know and trust, of an experienced local plumber to take a look. A wrinkly old one will know the trouble. Advertising websites where the traders pay to be listed are a poor source, especially if they are disguised as recommendation sites.

We used lime based paint as I wanted the walls to breathe esp as it’s a bathroom with no windows.
My house is also an upside down house so this bathroom is on the ground floor and about 5 ft away from the main waste drain. There was never a visible soil pipe as I suspect it was all connected underground. @PigletJohn

I looked at some online solutions and poured baking soda with white vinegar down. I’ve not checked the status of the bathroom yet as am currently sat outside sons school waiting for his A level results ( that a while other thread)

Anyway thank you so much for the replies and suggestions .

@FamilyOfAliens thank you

@Alexalee fingers crossed mine sorts itself out too. I’m not sure if it’s a combo of sealent and adhesives I can smell too.

Pictures of new bathroom as requested. The toilet is not situated where the sink used to be and vice versa

Gosh that is beautiful. Hope the smell goes soon and you can enjoy it.

It's looking really nice!

It’s not valspar paint is it? When we used valspar we thought we had a gas leak. The smell wore off after a few days.

That's gorgeous! Hope you the smell sorted.

Thanks guys I do love the look but that bit was down to me. The building side I should have total faith that they did their bit properly, but sadly the smell is stronger than ever. If I called another plumber in I fear he would want paying just so that he could shrug his shoulders and say something vague and non commital. They were supposed to do my other bigger one but now I don’t know what to do.

Do not pay the builder until the smell is sorted. If you didn't have it before it must be down to something they have/haven't done.

So today I definitely identified that the smell, (really is a pungent sewer smell) is coming from the shower waste area. The sink, the toilet all seem fine. But the smell is so bad from the shower that I don’t even want my son to sleep in his bedroom ( it’s an en-suite )

We have a basement shower and we get this when there isn't enough water in the pipes! It smells like rotting eggs!!!

You need to run the hot water and fill them up - run for 20 mins. Let us know if it makes a difference.

Happens every time we go away!

Apparently the pressure of the water keeps the methane gas down and when unused or brand new, the gas leaks up and a smell is formed. The water evaporates and lets it in.

Methane is odourless.

you should be able to fill the shower trap with a cupfull of water. No need to run taps for 20 mins (unless the design is so bad that detritus is flowing up the pipe to the shower).

However some shower traps have a lift-out pot that is intended for removing hair and toenails. Possibly if this is missing the trap would not work.

Thanks @flouncyfanny
@PigletJohn yes we do have one of those lift out pots in the shower and it’s got water in it so I don’t think it’s a dry p trap.

After yet more googling And learning about such things as bio films and bacterial ly emitted hydrogen sullied gases ( not methane then ) I’m worried that the builders have damaged some pipe work possibly going into the main soil stack which could be seeping sewage under the floor ???

But the sink doesn’t smell, just the shower trap area. Arrghhhh !

Have you ran the hot water through it yet and filled them up?!