Excessive Window Condensation

luckwudaveit

We live in a 1960s Wimpey semi detached house in South Lanarkshire. We moved in 15 years ago and in the last few years, the condensation on the bedroom windows has increased considerably, along with black mould above the window. We changed the window in the main bedroom last week and if anything, it has made it worse. We have tried sleeping with the trickle vents open, air brick clear and uncovered and the bedroom door wide open - it made no difference.

We've looked online for various companies to come and survey but don't really know how to approach it for the best. Some are focussed on installing ventilation and others on damp proofing, but none seem to survey for all possible causes. Possible causes are failed cavity wall insulation, failed wall weather proofing or not enough ventilation (but see above). Or it could be something else entirely.

A few years ago, a pillow was left against the wall and this caused damp on the wall, with the plaster coming away. Once the pillow was removed, that particular issue stopped. Likewise behind the curtains if they are pulled right back.

Any advice on what type of company to approach would be greatly appreciated.

FreeBear

If you get a damp proofing company in, they will probably find rising damp in the bedroom (yes, I have seen one make this claim with a damp first floor wall)...

What temperature do you heat the bedrooms to overnight ?

Have had issues with damp caused by condensation here in the past. But since maintaining a minimum temperature of 16C throughout the house, I only get a small amount of condensation on the windows, and that is only in the depths of winter.

Rugosa55

I had this problem in a flat I used to live in. We had someone to come and look around but we were told there were no issues with the building. It was a fairly new block of flats. We bought a dehumidifier which helped a bit especially when drying washing. Kept the trickle vents open too. I still had to wipe the windows every morning. Leaving the water would make things worse. In one corner of the main bedroom we had water on the wall and the floor during winter! We had to move the bedside cabinet from there until spring when the problem stopped. I struggled with condensation for the entire time I was there. Airing the rooms before bedtime seemed to reduce the water on the windows the next morning but it would make the whole flat cold. 

luckwudaveit

FreeBear said:

If you get a damp proofing company in, they will probably find rising damp in the bedroom (yes, I have seen one make this claim with a damp first floor wall)...

What temperature do you heat the bedrooms to overnight ?

Have had issues with damp caused by condensation here in the past. But since maintaining a minimum temperature of 16C throughout the house, I only get a small amount of condensation on the windows, and that is only in the depths of winter.

We haven't really had the heating on yet this autumn, maybe an hour or so in the evening. The heating is always off overnight. But even in the winter when the heating is on until around 9.30pm and with the thermostat at 19.5C, we get condensation.

The other odd thing, is my daughter's back bedroom suffers with condensation too, although not as bad as she's the only one in the room. But her bedroom doesn't have an external wall beneath it as there is a ground floor extension.

luckwudaveit

Rugosa55 said:

I had this problem in a flat I used to live in. We had someone to come and look around but we were told there were no issues with the building. It was a fairly new block of flats. We bought a dehumidifier which helped a bit especially when drying washing. Kept the trickle vents open too. I still had to wipe the windows every morning. Leaving the water would make things worse. In one corner of the main bedroom we had water on the wall and the floor during winter! We had to move the bedside cabinet from there until spring when the problem stopped. I struggled with condensation for the entire time I was there. Airing the rooms before bedtime seemed to reduce the water on the windows the next morning but it would make the whole flat cold. 

We also bought a humidifier and ran it during the day. Initially it collected some water but then stopped collecting after a couple of hours. Condensation returned again at night. I'm lost with it all.

FreeBear

I'm assuming you have double glazed windows - How old are they ?

I had my DG windows (installed around 1976) replaced recently, and that cut the amount of condensation forming on the windows. Unless your windows are old & falling to bit like mine were, replacing probably isn't an option. What might help is a secondary glazing - There are low(ish) cost sheets that can clip to an existing window. This might help to reduce the amount of moisture condensing on the windows.

stuart45

Is it definitely cavity walls, and not Wimpey no fines?

luckwudaveit

FreeBear said:

I'm assuming you have double glazed windows - How old are they ?

I had my DG windows (installed around 1976) replaced recently, and that cut the amount of condensation forming on the windows. Unless your windows are old & falling to bit like mine were, replacing probably isn't an option. What might help is a secondary glazing - There are low(ish) cost sheets that can clip to an existing window. This might help to reduce the amount of moisture condensing on the windows.

Yes, double glazed. We suspected the ones here were quite old, so we replaced our bedroom window last week. It's actually made things worse!

luckwudaveit

stuart45 said:

Is it definitely cavity walls, and not Wimpey no fines?

I'm not sure what 'no fines' is but the walls have the filled holes all around the building which I presume is from when insulation was installed? Edit: The outer walls are brick construction with rendering / roughcasting in places.

stuart45

The insulation can settle at the top, causing cold spots. When CWI is installed, unless it's done properly there can be voids. You can check the temperature of walls etc with a surface thermometer. Anything at or below the dew point is where condensation will be forming. Damp walls with be colder as well.

RobM99

My initial thought is where the moisture is coming from. Do you dry clothes over a radiator, for example?