External insulation for cavity walls?

4 Sep 2013
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United Kingdom
Hi guys, I've searched the web but couldn't find the answer I was looking for so thought I would post it here. Our house was built in the 1930's and I'm sure it is cavity wall as the pattern of the bricks point to that. Our energy efficiency is a E and the house gets rate cold and takes ages to heat up despite the rads being boiling hot, I know there is other things I can do such as draught proofing (which I will) but I was thinking of getting external insulation as the exterior of the house is in need of attention (discoloured + worn bricks + a few cracks). I know that the condition of the walls need to be good for external insulation but my question is can you have external insulation for cavity walls. the only info on the web I found said you must have solid walls for external insulation. I don't like the idea of cavity wall insulation (although we might already have it) as those cavities are there for a reason and would hate to get damp or any other problems. External insulation would improve the look of the house and potential stop cold air coming in/heat escaping (45%) but not sure if having cavity walls gives problems if you have external insulation. All the websites only list cavity wall insulation as a solution to improving heat loss when you have cavity walls.
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Plenty of houses with cavity walls that have been insulated post-build without problems. A ventilated cavity will have a draught running through it that sucks the heat through the inner leaf so adding external wall insulation won't help at all and will cost a packet by comparison with cavity insulation.
ok thanks, it was a case of improving the apperance of the exterior of the house anyway just wanted to make sure the house wasn't going to sweat or something.
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Had any quotes for EWI yet?

You might change your mind when you compare them to cavity infill...

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