Cold loft insulation is the process of insulating the floor of the loft – meaning the heat never reaches the loft. This means that the temperature of the loft may vary much more than in the rest of the house – it can get very hot in the summer and cold in winter. Bear this in mind when you put the loft to use for storage.
A cold loft insulation is usually undertaken with glass or mineral wool, placed and packed in between the wooden beams (joists) on the floor of the loft. The standard height of the insulating material is usually around 250-270mm (roughly the same height as the joists spanning the loft). If there is already some older or thinner insulating material present, one can simply top up the insulation to save some money on materials.
When installing, the insulation should be placed above any plumbing to keep pipes warm and reduce the possibility of the pipes freezing. Any electrical cables should be laid above the insulation. If you opt for cold loft insulation you will need raised boards, or have cross-beams installed, to be able to use the loft for storage.