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We have a house that is about 70 years old and only over the last 4-5 months we have noticed a strange smell coming from where the concrete floor meets the wall under the bay window internally. It smells like a musty/cat pee smell (no we don’t have a cat/pets) and I can’t seem to find out why or where it’s coming from. The carpet is dry to touch and when I was fitting the skirting about 3 years ago there was a gap of about 10mm between the concrete floor slab and the wall which was filled with very dry sand which I raked out and filled with SIKA SIKAFLEX sealant. Outside there is a small gap between the crazy paving and the bay wall where we get ants along there and did once get them on the inside of the bay before I filled the gap. The problem has been only the last 4-5 months. I have posted pictures of the internal and external of the bay window and the smell is only from the internal of the longest edge. Any help in getting rid is greatly appreciated. Thanks.

Some types of ants do have a smell and house ant Tapinoma sessile is one of them.

Thanks, I have heard of that. Would it be like our smell? Ammonia almost?

They report more like blue cheese, I take it the sealant has set and no external drain lines!

Yes the sealant has set and no lines underneath. Thanks for the info.

I think I'd be lifting that underlay to check for any signs of damp...

Thanks. I lifted the underlay but it doesn’t look or feel damp. We have those brown floor tiles on top of the concrete.

Just as an update, we had a pest control company round today and they couldn’t see anything to cause the smell. Those particular ants apparently we don’t get in this country so I guess that rules that out. They also said that the damp proof course is good and a thermal camera check only highlighted some cold spots. We will get more heating into the room and keep the trickle vents open still and see if it improves.
Thanks.

It is strange, I wondered if it was the underlay leeching a bit of smell. Have you had the carpets cleaned as the chemicals used can give a latent whiff? You can neutralise the smell with baking soda which will absorb any ammonia. You have eliminated most possible causes like pee, mould, damp. I guess you could check if there is a gas feed coming in under that point.

DWD

Thanks for your advice. I have put a layer of baking soda right between the carpet gripper and the skirting board and I’ll leave that overnight. The gas line for the old fire is capped outside and runs over the ceiling. The carpet is 3-4 years old and has not been cleaned as it’s not in heavy use and I can’t smell it on the underlay but I can smell it on the edge of the carpet that butts up to the skirting. I think we will call a damp company just to double check after I take up the baking soda.

The baking soda will show any evidence of dampness as it will clump. Keep us posted, this is a mystery.

DWD