Noise - Environmental - Insulating the Home - Roofs/Rooves
It is important to ensure that the roof is adequately insulated when the noise is above the house; most likely this will be from aircraft noise. A lot of people (and some authorities which should know better) think that the roof space has already been insulated. However, they have been thermally insulated and materials that are good for thermal insulation are not good (on their own) for sound insulation -see the insulation/absorption section of this site.
The sound insulation of a roof can be improved either by increasing the mass and structural integrity above the ceiling (e.g. by boarding the roof space) or by improving the ceiling below - here.
An external reference is to the proposed revisions to the Building Regulations which cover conversions and suitable sound insulation treatments to ceilings.