Trickle vents

Open the door and ventilate the room 1 hour a day.
I can guarantee it will work, but you already know that as you have tried it.

Back in the early 90s spotlights in ceilings became popular and the insulation in loft had to be removed and there was a 18 month nightmare for me with constants call backs because of pealing paint and black mould on ceilings. It improved with flower pots put over lights and insulation put back. Now the modern led lights are fire rated and can be covered.
The problem was cold surfaces and warm humid air but apparently it was all my fault as never happened before. No amount of door opening or window opening was going to stop the problem which is the same on car windows. Constant drying of the windscreen with instant water forming back on the glass first thing in the morning. However. Air con has dehumidifier built in and 30 seconds blast and window is clear.

I will when I get home. If you zoom in you can see small droplets on the mini trunking. When I opened the back door within a few minutes both walls were bone dry. Would that not point to condensation?

Michaelsf90 said:

I will when I get home. If you zoom in you can see small droplets on the mini trunking. When I opened the back door within a few minutes both walls were bone dry. Would that not point to condensation?

Click to expand...

Yes, condensation.
Curable by ventilation.
Made worse by sealing the room and making it hot.

So what would be the best permanent cure? A dehumidifier for winter months or an extract fan? The extract fan would only come on when lights are on. We cant have a trickle vent installed in a composite door

Michaelsf90 said:

So what would be the best permanent cure? A dehumidifier for winter months or an extract fan? The extract fan would only come on when lights are on. We cant have a trickle vent installed in a composite door

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Open the door daily.
This is the only safe and working way.
Unless you want to waste money on a dehumidifier.

johnny2007 said:

Yes, condensation.
Curable by ventilation.
Made worse by sealing the room and making it hot.

Click to expand...

The making a room hot isn't quite true, a warm room holds more water vapour than a cold room , it only becomes a major issue when you reach 100% humidity, and then touches a cold surface ... a cold room is just as bad as 100% humidity is reached sooner. hence why it is suggested even if you don't use a room in your house that you should have some background heating on in winter , otherwise that 'cold' air can't hold the water vapour and you end up with much more damp and black mould

As has been said , open up the door or get an extractor fan fitted . The only way to clear excess moisture in the air is by ' purge ' ventilation ( eg opening windows and doors ) . It is a very common myth that trickle vents will solve this, the industry was told in 2002 to put them in rooms with fuel burning aplliances ( open fires , woodburners, rayburns etc) purely for background ventilation to prevent the build of Carbon Mononxide.