Help! Why does my house smell damp 😩

[yoursweetpotatoesarebland]

Please be kind because I’m trying not to panic too much! I bought an old cottage about 6 months ago. It smells damp and I don’t know why.

It’s solid stone I think. Downstairs there’s a small single story extension which is unheated but has a vent and is my utility. I have a dehumidifier in there, it is damper than the rest of the house and hovers at about 50%. It has a door to it that separates it off from the main house which is almost always closed.
the rest of the house doesn’t show as damp on the dehumidifier- 40 max. But when I get back it smells damp and the other day I took a change of clothes out of my bag at a friends house and they smelled musty too. There’s no mould or damp patches anywhere or anything.

please help I am so worried that I’ve bought a house with a damp problem and I don’t know what to do about it!

If you leave the door to the extension open, this may allow more ventilation and may reduce the damp.

Laminate can hide a damp floor, but it will rise in bubbles.

Maybe the extension bridged the original damp proofing or is not damp proofed properly.

This video has some useful explanations of how this can happen (I am no expert and assume this is accurate because it seems to make logical sense, but if it's no good I am happy to be corrected)

i should say Piglet that you were hugely helpful with my mould problem. Op- I’m in Yorkshire.. where are you?!

How kind!

Just thought, where are you in the country? If you’ve got an old stone house, potentially with no foundation, you’re not in one of the areas currently suffering from groundwater issues are you? Would explain why you’re seeing damp now but not six months ago when you bought, or before…

Well it's winter and it's going to be damp. My dehumidifier is going ten to the dozen in my single brick bathroom extension. Before I had the dehumidifier, I could smell damp. I don't now plus it kicks out warm air.

@yoursweetpotatoesarebland You said the flowerbeds are quite high up the wall?
Care to post a photo?

And just to clarify, you are complaining the whole house smells damp, not just the utility?
After all the rain, and the winter, it’s hardly surprising an old solid wall house is damp.
Is it detached?

Yes detached.. I’m in Devon - it’s been insanely wet (one of the places that has rained every single day of this year wet…) and it didn’t smell damp in the summer.

it’s difficult to know how much of the house is actually damp because i guess you don’t notice it after a few minutes.. but I can definitely smell it when i come in and most of the house is open plan which would strongly suggest it’s everywhere..?

Someone at work suggested I check if the insulation is too high in the attic and blocking air flow in the house - I’ve got a roofer guy coming to clean the moss from the roof so i thought that might be a possibility to get him to look at it?

I will post a picture of the flower beds in the morning!

You could get some humidity meters, and put one in each room. If the doors and windows are closed overnight it will tell you if there is a particular problem.

Water vapour is lighter than air and will rise through a house until it can escape (or condense into water).

An RH of about 50 is normal inside a house. Modern houses are drier in winter because there is less water in cold outside air, and central heating reduces its RH. RH is a measure of how much water is in the air, relative to what it could hold at that temperature. Warm air can hold much more than cold air, without having a high RH.

Bedrooms are usually damper by morning if not ventilated, due to breathing and perspiration.

Bathrooms are a lot more humid after a steamy bath or shower and need a serious extractor fan.

Wet washing draped around a home or over radiators will cause serious damp.

Insulation does not cause or hold damp, but water vapour that rises through the house needs to escape, normally through the gaps under the eaves between the roof and the walls. Sometimes people incorrectly stuff insulation right into the eaves, blocking this gap. It is easy to pull back and trim with a giant pair of scissors. It is good to be able to see daylight all round the eaves inside a loft. A loft should be cold and draughty (like the void under your floorboards) because it is not inside the heated envelope of your house.

I have an oil filled radiator on my boat that is set to come on a low temperature every night and it costs about £36 a month to run.

The flower beds need to be reduced to expose the wall and give it an opportunity to dry out.