In about the last 30 years many thing have changed in the construction of houses one of which being the introduction of insulation. Due to the fact that energy is not infinite and houses cost a lot to heat it was deemed essential to find a way to stop the heat loss and with this in mind windows became double glazed, walls became filled with a number of different materials and lofts were floored with fibre glass all in an effort to reduce heat loss.

Unfortunately this moved the areas of condensation which traditionally had occurred on the inside of windows where it could be wiped away to areas of the house not so easy to access, the underside of the roof.

If not dealt with the condensation on the roof rafters could lead to them becoming rotten.