To insulate or not insulate that is the question

To almost every house in our neighbourhood there seemed to be no question as to whether to have cavity wall insulation blown into the walls of their house or not. Looking at the information on the energy saving trust website I am not really surprised. With no perceived negatives, low initial cost and a really short payback period who wouldn't?

Last year an extremely persistent company visited our neighbourhood to sign us up to have cavity wall insulation. Their first offer was to blow insulation into the gap in our walls for £150 which reduced to £100 and finally £50 when they realised we were entitled to the additional discount as we had children living at home! I asked for some documentation on the type of insulation used and its 'R' values and was told that they had no information but what did I want it would only cost me £50 and save me loads!

The cavity is there for a reason and I would need further convincing before filling it up with some unknown material.

After some research I have found evidence that in some cases cavity wall insulation can bridge the gap and allow water to travel to the internal wall. It can cause internal wall condensation, corrode the wall ties and even (once the 'insulation' is wet) reduce the thermal performance of your wall.

I have looked at the opinion of people directly involved in building and surveying and decided that the risk to health and home outweighs any potential benefits.

For example the Sunday Telegraph columnist Jeff Howell: http://www.askjeff.co.uk/cavity.html and Premier Heritage: http://www.premier-heritage.co.uk/2009/08/cavity-wall-insulation-what-are-the-benefits/

Update: There is now a campaign group dedicated to helping those with failed cavity wall insulation - http://www.civalli.com/

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