Why have cavity wall insulation ?

I have come across many cases where house owners are advised by damp specialists to fit cavity wall insulation when they are experiencing condensation and mould problems. But the question is why?. Condensation and mould are caused by a damp environment whether it is a damp wall or damp air. Cavity wall insulation by its very title INSULATES, which it does well, but it is not a barrier against damp. If you suffer from a cold room or experince condensation and mould it is cheaper in the long run to call Damp Detectives for an Independent Damp Survey which will identify exactly what the cause of the problem is. You may well find that you don't need cavity wall insulation at all and that will save you a pretty packet.