What is this smell?? Out of ideas

[Frorg]

You can smell it as you enter the house or come down the stairs. It gets slightly stronger as you walk through the sitting room to the kitchen. Is not stronger in any one area (ie near sink, bin, fridge), just generally in the air.

Is reminiscent of the time a housemate left a bag of potatoes in a cupboard at uni and they went mouldy. Or perhaps the time there was a dead squirrel in my parents loft. But not as strong as that.

I have tried drain unblocker. Sink has bleach put down approx once a week anyway and probably zoflora once a week also. I have cleaned fridge, oven, microwave. Bins have been disinfected. Cat bedding washed. Everything has been cleaned. I have checked all drawers and cupboards, on top of the kitchen cupboards, and have removed kickboards to check underneath the cupboards.

I've washed the sofa covers, the cushion covers and curtains. I've shampooed the carpets (so all furniture has been pulled out). The washing machine has been run on a couple of hot washes.

The kitchen window is permanently opened a crack, and opened wide when cooking. The bathroom window upstairs is also open a crack all the time so there is through air. When we're home the back door is open. All windows are opened wide for at least half an hour daily, usually more.

I'm at a loss as to what it can be, especially as I can't pinpoint the exact location of the smell, it's just in the air. It's been almost two weeks...

We had a vile smell - finally tracked it down to ds's bedroom. Really thought something quite big (thinking bird, rat, person...) had died under his bed. I crept in in rubber gloves and bin bag and my dm and ds bringing up the rear. Did a fake scream and run they jumped out of their skins and made me titter turned out to be .............................................................................................................................................................................................................................................................................................................a spilled water bottle!! It was foul. (Newish carpets too!!)

Dead mouse, they stink

Have the carpets got damp/could Tiddles have tiddled without you realising it?

I think it's probably a rodent too. Check there are no big gaps around air bricks or waste water pipes. Attach some fine aviary mesh to air bricks and plug gaps around pipes with a suitable filler. That should stop rodents etc. entering you house.
I recently had a foul smell in my kitchen and it turned out to be a bag of mouldering spuds.

Check your light switches and sockets. Sometimes they can overheat, the plastic starts to melt inside and weirdly it smells almost exactly like a dead mouse. If it is a socket or switch you need to get it replaced straight away.

Rodents smell gassy rather than musty ime.

We had something similar once at the bottom of our stairs, it took me ages to pinpoint it and the smell got worse. Eventually worked out that one of the DC had left a carton if milk in their school bag which had expanded in the warmth by the door and exploded

A slight leak in the waste pipe underground outside but near the house. He had this and our hall used to have a very slight smell, worse in mornings and after rain. We found it when we had the drive re-done and the smell has now gone.

Thanks for all the ideas. I'm still at a loss.

It is definitely not something unwashed/unclean.
None of the furniture/clothing/carpets smell.
I've moved everything, nothing dead to be seen.
Unless it's behind washing machine but it doesn't smell stronger around there.
I'm thinking the rodent in wall/floor thing is looking most likely. Yuk.

It might be getting fainter, or that could be wishful thinking. Or perhaps where it's been a bit cooler the past few days.

Check your tins!
We had a punctured tin- you couldn't see it, it was in a multipack. Took ages to track down the vile smell.

Leaking roof? Look up. Any damp patches where wall meets ceiling? Or above windows?

Do you have a coffee machine? If so wash out the bit that you stand the mug on. A few weeks worth of drips of coffee accumulating in the bottom and it starts to smell.

My guess would be a dead rodent under the floor.

From what you have said I would infer that the smell could be in the air from an outside source.

Reasons for this:

"It gets slightly stronger as you walk through the sitting room to the kitchen. Is not stronger in any one area (ie near sink, bin, fridge), just generally in the air."

"The kitchen window is permanently opened a crack, and opened wide when cooking. The bathroom window upstairs is also open a crack all the time so there is through air."

This suggests an outside source.