No insulation (and no space for it) = damp

MouldyOldDough

ThisIsWeird said:

Sounds like a good outcome, MOD.

Let the damp patches dry out fully, then spray with mould killer such as 'Astonish'. That should bleach it nicely too. Hopefully it can then simply be overpainted with emulsion. If a stain comes through, then you'll need a stain block.

How did they insulate the ceiling?

ThisIsWeird said:

Sounds like a good outcome, MOD.

Let the damp patches dry out fully, then spray with mould killer such as 'Astonish'. That should bleach it nicely too. Hopefully it can then simply be overpainted with emulsion. If a stain comes through, then you'll need a stain block.

How did they insulate the ceiling?

Foam in the space behind them...........

MouldyOldDough

OK update...

The mould on the ceiling has become WORSE - we are currently getting the bedroom decorated.

The decorator has treated the stain with a "block" and is over-painting it.

But I am worried that the mould will return.

Where did the new mould come from ?

The roof has been re-tiled and is watertight.

My wife has been leaving the window open a 1/4 inch -24/7 - thinking that ventilation will cure the problem - but will it ?

I am thinking that this is where the moisture is getting in - having read that outside humidity can average 60% and internal humidity should be around 40% - leaving windows open is therefore akin to pouring water into a house through an open window.

Should we keep the house airtight or does ventilation help with damp ?

Where did the damp come from anyway ? Showers / washing drying on radiators (during the winter)....

Advice welcome

fluffymuffy

How long have you lived there & has it always been mouldy during your residency? Or is this a new thing compared to an earlier time?

Has anything changed in terms of home improvements? Such as new windows or cavity wall insulation?

Are there more residents? Or has someone retired or changed to spending more time at home? Do you use the tumble dryer less, in favour of using a clothes horse?

stuart45

You need to get a surface thermometer. Check the temperature of that surface at different times of the day and night along with the room temperature and relative humidity. If the surface of that part of the ceiling is at the dew point or below it, then condensation will be forming there. 
Mould needs the right conditions for the spores to germinate. Plasterboard provides the food, and condensation the moisture. Stain block stops stains coming through, not mould forming on the surface. 

ThisIsWeird

New photo, MOD?

In answer to your Q - no, leaving windows open will not, ever, cause damp and mould (unless actual rain comes in!)

Ventilation is key to mould prevention.

It is astonishing that you are still having mould with all the room ventilation you are undertaking. Do you keep the room door closed at the same time? If not, it could be from moist air from the rest of the house.

Really, we need to try and determine whether this mould is coming from surface moisture - condensation - or from behind - a leak.

Photos, please.

MouldyOldDough

fluffymuffy said:

How long have you lived there & has it always been mouldy during your residency? Or is this a new thing compared to an earlier time?

Has anything changed in terms of home improvements? Such as new windows or cavity wall insulation?

Are there more residents? Or has someone retired or changed to spending more time at home? Do you use the tumble dryer less, in favour of using a clothes horse?

23 years and no it has not always been mouldy

We've had an extension and new conservatory but these were this year - the mould started about 5 years ago

my wife has always aired washing on the rads.

no tumble drier

no other changes