Why does my room smell?

[sunshine244]

Every early spring to late summer my bedroom starts smelling. Not a horrendous smell but a relatively strong whiff of musty type smell. It's really obvious when you first walk in but once in for a while you don't notice it much. I got the first whiff of the year today even though its only January, but it was a warm day.

My room is an attic room. Old stone building but in good condition. New carpets, it's definitely not the bed or other furniture. I've tried sniffing around and other have too. Everyone can smell it but there's no obvious source. No known issues with birds, bats, rats etc and no unusual sounds. No damp, no mould.

There's obviusly no loft but there are eaves running both sides the whole length of the top floor. Both sides have cupboards at the opposite end of the house and there's no smell in there (although i can't get to the far end due to no flooring). The smell is only in my room. It's definitely not me because it's actually worse if we're away for a week (probably because the room doesn't get aired) nor does it happen elsewhere. The room doesn't go to a point so there's a small roof space at the top but this will also run the whole length of the house. The corridor outside the room doesn't smell at all.

Could smell be coming through from next door? It seems unlikely because the walls are thick. Next door is quite run down and can often see condensation in the windos but I've never been inside.

Help - I've tried all sorts of cleaners, sprays etc and it comes back every year.

When we had an old stone house we had this.

it was worst after holidays when the house had been shut up for a week or two.

no advice I’m afraid we never did work out what it was.

Was it just in one room or several?

Old stone building. Musty smell.

Next door with damp / condensation.

Worse if you're away and the room doesn't get aired.

I guarantee the damp is in the mortar of the stones and as the mortar rots that's what you're smelling. It's definitely coming from next door.

Ugh! Is there anything I could do about that from my side?

I don't think talking to the neighbours is likely to help (I had an issue with their blocked gutters damaging my property at one point and they were entirely unhelpful).

You could try getting in a surveyor / builder with expertise in older / listed buildings and see if they have any suggestions.

It could possibly be damp due to lack of air flow , we had this in our walk in wardrobes , a musty smell ,a de humidifier solved this for us . our house isn’t old or particularly damp but with humidity and overnight breathing it was amazing how much water was pulled out of the air .
We bought a Clarke portable dehumidifier from machine mart and move it around the house when needed .

It could be next door. Make an excuse to knock on their door and see if you can smell anything when they open it?

Are you leaving a window open daily for a period of time to ventilate the room and let the musty smell out?

Could it be in the paper/paint of the walls . Sometimes if a room isn't properly stripped and sanded, old substances can smell e.g. paste or types of old paint.

A temporary fix might be to buy an electric dehumidifier. Takes all the water and damp smell out of my spare room.

It could be damp in the eves. We recently had a leak in the bathroom- the plywood boards got wet (very wet) and are going to take a while to dry out thanks to their location. The bathroom smells musty first thing but once the window is open and air is circulating it gets better. We've been told that once the boards are dry the smell will go.

My first thought was damp or mouldy insulation

Are you opening the window daily and leaving open for a good free hours of airing out the room?

Thanks for all the suggestions.

Yes - I air the room lots. It doesn't seem to make much difference.

Wouldn't smell of damp or mould be worse in winter when the air is usually more humid? The smell entirely vanishes over winter. It's days that are hot outside that are particularly bad. Which is why I initially thought maybe bat droppings in the roof or something.

Have you painted the room recently? We had an awful smell appear in our living room, took
the floor up, put a vent in, had the roof/chimney looked it. In the end it was paint on the walls that must have been faulty or old. Repainted the whole place in shellac paint and the smell went.

I wonder if there is something living under the floorboards that you are smelling?

I just had an idea...copy and paste your post into chatgpt and see if it can think up any suggestions of what the smell could be...it's worth a try especially if it's coming back year after year and you can't find what's causing it

Do you have cluster flies hibernating/coming out of hibernation? They release pheromones which can give an attic room an odor.

Not sure that is a particularly musty smell though

We occasionally get mouse smell. It's a bit like gas and stronger through the summer

Is your neighbor’s house attached to yours? If it isn’t I don’t know how their house would affect yours.

The only thing I can think of is when we had old wood window frames, they would always give off a smell when it was warm. It was a kind of wood fungus- dry rot.

Mold/fungus smells are stronger when it is warm because they grow faster in warmth than in the cold. For example, dry rot doesn’t grow unless it is over 20C

I don't think so - never hear anything and the room underneath is fine

Not that I know of 🫣

I lived in a house with mice a few years ago. It was really obvious as heard them running around at night, found droppings and things chewed etc. Nothing obvious here.

Yes - it is. It's really quite rundown - their windowframes do look rotten so that could be where smell is coming from. Their now grownup child used to live in the room next to mine and I suspect it's not being used now. Always lots of condensation in that window in particular so damp could be coming through. I didn't think that would be possible with thick stone walls though.

I've ordered a dehumidifier to see if that helps.

There is a particular must/mould/damp smell from old stone houses. I do think it probably is something like this rather than anything with legs.

Apparently there are sniffer dogs who can seek out mould. Maybe you can see about hiring one or a less expensive option would be to get a moisture reading device or a thermal camera from amazon and go around the house looking for damp/cool spots.

For ventilation you could try the German approach of opening windows fully on opposite sides of the house for about 5 mins and then closing them, once a day. It allows the air to cool down without cooling down the walls, apparently. It's gone viral at the moment because someone on tiktok has dubiously translated it as "burping the house".