Humidity Problem

FlipperThePriest

I Hope this is posted in the right place; it's not directly related to Renewable Energies, but I'm guessing people in that field will know specifically about humidity and ventilation in the home.

I moved into an old 2 bedroom cottage after Christmas. It's not my place so don't want to be spending much time/money on it, but there's a new baby on the scene so too much humidity something of a small concern.

It was very cold during winter so I went around and filled any drafts I could find (in skirtings and doors) and insulated a lot of the attic. I also insulated around corners where light and draughts were coming through.

Now that it's mid-heatwave the humidity is mega. It's 80-85% at night, 65-70% during the day. I guess humidity has always been a problem in this place as the ceilings are a bit saggy, it was damp initially, there were woodlice and various hints of humidity when we moved in. Also not a huge amount of light - plenty of trees around.

I went and bought a 10 litre dehumidifier and ran it for 24hrs in the bedroom. It collected 2-3 litres in 24 hours. Moved it into another room where it is now running. Humidity is already starting to rise back up to 60% in room were it was bought down to 52% just hours ago.

There are 2 water tanks open in the attic? Would it be an idea to cover these with foil? Is it possible that water from these is evaporating and leaking into the ceilings during high temps?

We had a mold problem in the bedroom, did a good clean around before running dehumidifier. Also, we always have windows open when possible and run extractor fans whilst cooking etc so we aren't careless with contributing ourselves even though it's inevitable I suppose.

It's not a serious problem but is there anything you think might help? Will covering the water tanks help at all? Don't want to be running a dehumidifier 24/7 either.

Any ideas?

Thanks

MicktheMan

I'll try to keep this post short as I could write for days on this.

Point 1: During the summer the humidity is generally high everywhere so it being high in the house is not an issue. Stop with the dehumidifier, you're wasting your time and money.

Point 2: Mould caused by excessive humidity in a building is an issue during the heating season when the building is either under ventilated, inadequately heated, there is excessive moisture generated or a combination of all three.

Do you know what the indoor humidity levels were during the winter?

So the questions to ask yourself are:

1. Is the house adequately heated during the winter?
2. Is there sufficient ventilation? How is it ventilate?
3. Is there excessive moisture generation? (such as drying clothes indoors on a rad or clothes horse)


On a general note, old buildings which have been "upgraded" with better sealing windows and doors are particularly prone to higher humidity levels because of their large thermal mass and the absence of damp proofing when they were originally built. This extra moisture was dealt with by having natural ventilation around windows/doors and a fire in the grate 24/7/365. When this natural ventilation and heat has been "upgraded" without due care very often mould (in some cases very severe) is the result. As has been said many times before, old building need to be treated differently to modern ones.