smell of damp plaster

20 Sep 2009
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United Kingdom
Hi all,

I had a bedroom re-plastered about a year ago. Occasionally we still get the smell of damp plaster. I'm thinking that either water is getting in from the external walls or that the levels of moisture in the room are causing the problem. There are no signs of damp on any of the walls. The room does not appear to have air brick type ventilation - should there be some sort of vent to the outside? Am trying to get a feel for the nature of the problem before taking chunks out of the walls.

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Drying plaster has a smell all of its own, it’s unlikely you are still experiencing it; what you’re most likely experiencing is the musty smell of damp. This could be a result of water penetration which should be relatively easy to track down; what type of walls do you have? Do you have double glazing? If not due to water ingress, the most likely cause is condensation due to a build up of moisture within the room when you’re asleep.

Natural ventilation is very important if you have double glazing fitted particularly in the bedrooms. Do you open the windows? Do you have trickle vents fitted to the windows? One other main cause of condensation is drying washing in the room; moisture has to go somewhere & will usually condense on the nearest cold surface.
Thanks Richard.

There are double glazed windows in the room - i don't think there are any vents in the window frames but the windows are regularly open. The walls themselves are brick with an external render. should i use some sort of damp meter to track down the damp area? as i said there are no external signs of damp.

many thanks

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As R.C posted could be condensation, apart from a Hygrometer survey to determine this hire or buy a De- humidifier,that, when turned ,on will give you a percentage reading of the relative humidity in the room, above 60% you have a problem with condensation and it will draw excess water from the air reducing the R/H percentage.Bricks are designed to breathe and sometimes the outer rendering will cause interstitial [ cavity ] condensation as they cannot perform, could be also worth investigating. Hope this helps.
Thanks Dave, think i will hire a hygrometer and a dehumidiifier and see what happens. The lack of any visible sign of damp is puzzling though - its been going on for a while and i would have expected to see some patches.
Hi all,

Hired a handheld dampmeter today and tested all the walls and the ceiling for moisture content - all checked out fine. Still have the smell of damp in the room - it seemed to get worse following heavy rain a couple of days ago so i suspect some sort of water ingress. I may have to pull down all the plasterboard walls to look at the external walls - what a pain!!

any other advice?

Hi, Just wondering did you get this problem sorted, i have the same issue, had some rooms re plastered over a yr ago and if we have heavy rain, and then i warms up we get the smell really bad, also, if its a fine day and the wife get the ironing going the steam causes this smell to come back almost straight away?
I've just seen a tile missing on the roof and i'm wondering if water is running into the cavity, but as with yours i've no sign of damp anywhere.
It's really puzzling me and i'm getting quite worried now.

Anyone else got any ideas?

Cheer's Chris.
we have the same problem, living room ceiling plastered about a year ago. When it rains a smell of damp plaster in the room, which disappears when it stops raining, but no sign of damp anywhere. Any ideas?
I managed to track it down to the white matt emulsion paint i used on the 3 different room ceilings with the problem, i'm sure it was wickes paint.
I hav'nt re painted it yet.

Very interested in your post re the culprit being the matt emulsion - we used Selco, which we have never used before, but now think we will cover again with a Dulux emulsion. How did you track it down to the emulsion? (It will be a relief is this is where the problem lies, as it does get quite worrying).
It drove me mad for months, after thinking long and hard over what i'd done to the 3 rooms at the same time, i narrowed it down to painting all ceiling the same weekend, the smell is only in these rooms, i got some steps and smelt all 3 ceiling in various areas, i may have looked a little strange to passers by looking in, but thats what it is! cheap paint i suppose, i had used it watered down first to seal the new plaster also.
When something smells it's the particles being emitted that you smell.

That's why those room deodorisers get smaller over a time period.

Paint can't do that.

Once it's dry it cannot emit particles or it would end up disappearing. Therefore it can't keep on smelling. Water based paint doesn't really smell anyway.

That's why gloss stinks when first applied - the particles are emitted and they go up your nose which detects them. As it dries the smell disappears.

Look elsewhere for you problem.

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