Problem with damp inside a wooden shed

by June
(Shetland UK)

I insulated my wooden shed (which sits on a concrete block) using foil faced insulation that comes on a roll. I then used hardboard to line out the inside. There is clearly a problem with damp as the hardboard has gone black and I’m having to run a dehumidifier 24 hours a day.
SO -
can I simply paint the shed interior and if so what sort of paint should I use?
what can I do to rectify the problem that
a - won’t be costly
b - won’t, hopefully, require ripping all the insulation and hardboard out

Thank you for your help

Comments for Problem with damp inside a wooden shed

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Foil insulation isn't great for sheds
by: John

Hi June,
From your description it sounds as though you have sealed the shed pretty well and there is no ventilation. Foil backed insulation doesn’t ‘breathe’ ie. Allow moisture in the air to pass through it and escape. It sounds to me as though the moisture in the air has condensed on the foil creating a damp atmosphere on the surface of the hardboard. This is just the sort of environment where mildew thrives.
Unfortunately, without having seen the shed or pictures of what you installed, it sounds as though it will need to come out.
You can read more on why foil backed insulation isn’t a good answer to shed insulation here
And also my discussion on shed insulation here:



Thank you
by: June

Thank you John, that is not great news - I had watched a video on ‘you tube’ which showed how to insulate a shed in a short time and the bloke doing it was using either the same insulation I used or something very similar. Of course what you say makes absolute sense when I think about it.
You live and learn!!
Kind regards

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