HELP. Horrible smell in 2 kitchen cupboards.

[Rhysandswife]

We moved into a 5 year old new build six months ago and I'm being tormented by the smell of something disgusting, kinda fishy coming from 2 of my kitchen cupboards. Weirdly, the one next to them smells fine. Every time I open the cupboards I want to scream. I've scrubbed the hell out of them.

I had a handyman out and he removed the kick boards and there was nothing under there, barely even any dust, no sign of damp or wet patches. I then made him remove the back of the cupboards too (in desperation) and still nothing. But, when he first opened them he said he couldn't smell much but as soon as he took the back off the smell hit him.

So what could it be? It can't be anything dead, there's nothing there at all and it's as strong as it was 6 months ago.

Please help.

It's pitch black so I can't get a pic of the outside, but there's nothing there. Just house, then pavement. No pipes, brainwork etc.

It's obviously haunted. Maybe the smell will go away after Halloween 👻

How long has the smell been there for?

In the wall or under the floor sounds like a dead thing, sorry.

Sound like something died in there to me as well. We had a rat die in the cavity wall behind our downstairs toilet, the smell was unbearable. Rather than tear the wall down we sealed the room - tape around the door for several weeks, LOL.

I don't think it's something dead because the smell has been there for the 8 months we've lived here now. And I swear it's getting stronger now.

To recap:

-This is the main cupboard which makes me want to gag when I open it, the ones on either side smell a bit but nowhere near as bad.

-It's not the items in the cupboard as we removed them all for a week (and cleaned them) and it was just as bad while empty. The cupboards themselves have also been scrubbed and bleached

-The smell is behind the cupboards- when handyman/electrician took the backs off the cupboards they said the smell was overpowering behind there

-No pipes of any kind behind the cupboards

-Outside of the detached house, no pipes or drains

-No bathroom above

-Not near the sink, dishwasher or fridge and we don't prepare food there

-No damp, rotten food, signs of anything whatsoever behind/under cupboards (agreed by both handyman and electrician)

...

Here are the photos. As you can see, it's the corner of the kitchen/house.

Body under the floorboards put there by the previous occupants. I'm half joking but...

The cupboard in the other side of the corner. What's in there?

there may be some dead space in the corner, where none of the units quite reach the wall.

Have you tried removing one of the units? It shouldn't be too hard. Then you can look properly behind.

Even if something died in the wall, I wouldn't expect it to last that long or be that strong, there would be a plasterboard partition in the way.

I have considered this in my more desperate moments 😂

@Skunkaniseed in the corner cupboard is plates and bowls (not much in there as I hate corner cupboards, pointless waste of space) and on the other side is just bowls, grater etc. Everything been removed and cleaned and cupboards fully bleached each side.

@CatherinedeBourgh can't remove the whole unit, but the handyman and electrician removed the backs of all 3 cupboards and the kickboards too, put lights under there and had a really good look around. Electrician (he was lovely) was under/in there for half an hour determined to help!

Can you cut a hole in the floor underneath and see if it's dead rats in the crawl space?

I had that for months and months. It got worse in the wet. Until I found a tiny hole in the outside brickwork. I blocked up and the smell went away. Eventually. I think dead rats smell until they totally decompose and then no more smells.

Decaying rodents smell like hot cheesy vomit, not fishy. Rotten potatoes oddly smell similarly.

Has the wall behind been skimmed? The first thing that came to mind is that either a ready mixed filler that's gone bad has been used (because that stinks of fish) or they've used a sealant/adhesive that's now breaking down and emitting a fishy smell, because some adhesives have stink too. I don't know what I'd do about it that wouldn't end up costing a bomb though.

Is the wall behind the cupboards painted differently to the rest of the kitchen? For instance painted, then the cupboards installed, then repainted, but not behind the built in cupboards?
I know there was a problem a few years back with some paints, eg https://www.bbc.co.uk/news/business-40655163

I suspect there's something under the floorboards under the cupboards.

The handyman who was here said if it was something dead the smell would be long gone by now, it's been 8 months and getting worse.

Not sure about the painted walls, or if it's been skimmed, I can't get in behind the cupboards to see. It's a new build but 6 years old now.

Oh and I think the floor underneath is concrete!

I was thinking of the valspar paint thing. There were lots of complaints about fishy smells even when painted over. Walls needed fully stripped back to plaster. I'd be surprised if there were painted walls behind kitchen cupboards in New build though.

Cab you remove the backs of the cupboards and empty/open doors for a week to air it all out? Maybe paint the wall will a sealant- some type of zinser?

I did leave the cupboards empty with doors open for a few days but it made no difference.

I could ask the handyman to come back and seal the walls with something (they're unpainted behind if I remember correctly) but he seemed to think it smelled of sewage and indicated a blocked pipe. But how would I possibly know? No drains, no pipes, all water running fine in taps and toilets flushing fine. And no toilet near it.

If your house is only 6 years old it should still be covered by warranty. Maybe contact the builders or failing that contact your insurance company?

I called the builders who wouldn't help, saying it's not structural and they can't help with a smell.

I’m going to call my home insurance now. Thanks

How did you get on with the insurance company? If someone thinks it is a sewage type smell, have you located an outside manhole even if it is no where near the cupboard? Drains run all sorts of weird directions (even under properties, including newish properties ours do). Once you have located a manhole (preferably the one nearest your boundary to the road,or wherever it flows) fill your bath half full with cold water then while someone peers down the manhole let out the water and check it flows through ok. Possibly a drain issue, it won't necessarily mean there isn't if it flows ok, there could be a cracked pipe for example but less likely if property is only 6 months old. Drain surveys either by your water/sewage company are a possibility if insurance won't help.

Sorry meant 6 years old 🤦‍♀️

It might be best to leave the doors and back panels off the cupboards to air it out.

WILD UPDATE

I phoned my home insurance who asked if I'd had the gas checked and I said no. They advised me to first, so I googled it and the smell could have been gas, so I phoned the gas line who said they'd send someone immediately. No, I said, it's not an emergency at all, this smell has been here for months! But she insisted.

Anyway LONG STORY SHORT we have an almighty gas leak from the hob that the wires lead down into the back of the cupboards! The guy said we have been extremely lucky.