Some years ago (6 or 7 I think) when their was a Government backed energy efficiency scheme on the go. Everything to do with saving energy was being given away, from loft insulation to boilers and light bulbs.
It was actualy scandalous the way the money was thrown around. Money was no problem .. the only problem was getting rid of it.. all £33M of it.
When it was over, I had to visit quite a few properties where the lofts were damp after the insulation guys had been and installed extra insulation. On each and every occasion it was the same problem. They insulated most lofts in 30 minutes or so .. they were being paid per loft. They had been throwing the insulation in and were in such a rush to get to the next loft.
The problems that followed were dampness in every case, all as a result of a shoddy installation. In every loft I had to roll up the newly installed insulation and pull it back and away from the eaves which had more or less become blocked by the extra insulation. Once the eaves were re- exposed, the air could once again flow across the loft and dry it out.
The reason that made people aware that they had a problem, was the damp marks all round the edges of the ceilings, nearest the outside walls.