I have recently discovered that my loft is not insulated. We have a large loft and can definitely feel the chill up there. The bedrooms are cold also so I think the insulation should make a difference.
Question - we want to eventually (2 years) do a loft conversion so if we put a load of insulation down now, will it get removed and replaced with something else when we decide to do the loft? i.e. Current approx. 700 pounds (labour & materials).
It will all depend on the material used do insulate the loft now if you can reuse it in the future, also the method by which the job will be done, influenced by the changes to the future loft space and of course - what fallows - is the price.
As to the guidance the thickness 220mm- 270 mm applies for new homes
any houses over 15 years old thats should be a minimum of 120mm on timer joists
100mm and is limited by the roof spacing and ventilation to allow breathability.
Insulation can be installed either at ceiling level or below the roof itself, although the detailing in
each case will need to be different. In most cases a ventilation path should be retained above the
insulation to carry away any condensation which might affect roof or ceiling timbers.