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Damp Proofing

What should we do about condensation, which started after installing new loft insulation and windows?

I think there are at least two causes - in the bathroom it is worse because of the humidity from showers and baths. The old leaky window helped but with the new one, even opening it every time we shower doesn't seem to be enough to stop the mould. I wish we'd known earlier about this as we might have chosen a window with a trickle vent.

Elsewhere in the house the problem is less severe and seems to be coming from the loft, where we have fitted more insulation. I think we need to look at improving ventilation there somehow.

Is a heat recovery ventilation system our best option? Do we need to do anything else? Who should we ask? We want to be as eco-friendly as possible. I also have chemical sensitivities so chemical options would be problematic.

Thanks for any input and experiences.

5 Answers from MyBuilder Damp Proofing Specialists

Best Answer

Have you actually got a proper extraction fan in your bathroom?
You can fit trickle vents on windows at any time.
Make sure your loft insulation hasn't blocked off air flow around edges.
If you opt for a whole house ventilation system i recommend this:



Answered 29th Dec 2011

You need trickle vents in the windows, these can be retro fitted so not a problem, you also need extractor fans vented to the outside.
When the loft insulation was done, check that the insulation hasnt been pushed tight under the eaves.
You need a good air flow in the roof space via soffit vents or roof/tile tiles.


Answered 29th Dec 2011

Hi, condensation can be a pain, yes it is a great shame you didnt get trickle vents on your windows, have you got an extraction unit in your bathroom? Does it have over run when you leave the bathroom? There are many products available all with different price brackets and shelve life. We have recently installed two heat recovery units on a restoration one for the bathroom and kitchen, a low carbon trickle unit cost price was £250 these units circulate air whilst returning the warm air back into the room. We also use a product from sovereign for whole house condensation control called 'Concure' great bit of kit with a worth while Guarantee. To solve your problem you need to focus on internal ambient temperature and air circulation and finding the right balance find more information on our website.


Answered 29th Dec 2011

I would reccommend installing a POSITIVE PRESSURE UNIT to flush clean air trough the house from the loft downwards.... This will also have a positive effect on cleansing your air of unwanted irritating chemicals and the units are recommended for allergy relief for this reason. A humidity control extractor fan may also be required for high humidity areas such as the bathroom.

Costs for supply and installation of a PPU are approximately £650.

Best Wishes

Corrie, Pure Property Care


Answered 3rd Jan 2012

Hi zoe_40

You could put trickle vents in the windows fitted.Or you could fit air bricks.

Hope this helps

Trevor & Mike


Answered 30th Dec 2011

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