What is this smell

[SomethingSmells]

I noticed a smell in an upstairs bedroom yesterday when we’d been out for the day and the house had been empty. My partner had been putting the children to bed in the room and when I came upstairs it smelt so bad that I told him to go and have a shower as I thought it was him! It’s a really strong sweet BO smell. I aired the house this morning and the smell appeared to disappear, however we’ve just got home after being out all afternoon/evening and the smell is back.

does anyone know what it could be? The room is clean and tidy, and I’ve hunted around for stinky clothes/shoes/nappies/food items/dishes and I can’t find anything

Wet underlay really stinks

If you have unexplained water don’t rest till you find the source - it will be very dangerous, disruptive and expensive if it results in a fallen ceiling or worse. If you have a tank in the loft which might be the culprit, make sure it’s properly checked over.

Sounds like the identifying the source of the water may give some clues.
If not, do the neighbours smoke weed? I once had some neighbours who did and it made my house stink (terraced house). Alternatively, have you painted the room in the last year? Paint can be contaminated with bacteria and smell like cat piss! This happened to me and it only smelled when the weather warmed up which was months after painting.

As someone who just pulled the bedroom floor boards, you may have a pest problem like I did. Found droppings, nests and a hole in wall under floor boards from old plumbing works that haven't been sealed up. In my case a few of the neighbours 'pets' (mice, her house is awful and falling apart and she is too lazy/ mad to sort it) migrated to mine. Look for any holes in the walls and fill with wire wool (rodents hate chewing it). Baking soda and peppermint oil are supposed to help with the smell.

Definitely concentrate on the patch of damp carpet and the source.
Not sure whether I'd prefer it to becoming from above or below!

Rip it up. Do share the body count! I mean erm, the floorboard damage.

Oh dear, it seems you have a leak. That's very, very serious. You need to find the source ASAP.

Could one of the children spilt milk.......that is an awful smell after a few days if not cleaned up straight away.