If you wish to make your heating system a little more efficient, you should consider adding insulation in your loft. This prevents heat escaping from the roof of the home, keeping rooms warmer. This can save money as your heating system can be turned down, or will not need to be on for such long periods.

In most cases, the task of insulating the loft should be well within the capabilities of the householder, though there are a number of companies who will do the work for you if the need arises.

The most commonly used material for loft insulation, particularly as part of a DIY project, is the mineral or fibreglass matting, which is usually provided in roll or slab form. It is available in a variety of thicknesses, from 100mm to 200mm, and typically comes in rolls 400mm wide. The total thickness of the loft insulation should be 200mm, which may be achievable by overlaying more than one piece of insulation.

Other common materials are loose-fill fibres, which are typically 'blown' into the loft. In most cases, this should be left to a specialist contactor. It is, however, possible to buy bagged loose fill insulation, which can be used to fill some hard-to-reach corners or areas.

Before Starting

• Do not use just a torch for lighting the loft. If possible, you should run an extension lead to the loft, and hang a suitable light from the beam.
• Check that ventilation is adequate. If you can see daylight beneath the eaves of the house, ventilation is probably adequate. Otherwise, ventilation should be added.
• Cracks and holes in your ceiling should be repaired, else warm air can rise through the gaps and cause condensation within the insulation. It may also cause loose fills to drop into the room below.
• Check the loft for any issues which may affect the installation - for example, leaks, insect infestations, wiring and hot water tanks will all require special attention. Water tanks should be insulated separately, and no insulation should be placed around electrical cables, as this can create a fire risk.

In most cases, the roll of insulation should fit perfectly between the ceiling joists, in which case all that needs to be measured is the length of the joist (so you can work out how many rolls fit in a joist), and the number of gaps between the joists across the roof; which allows you to work out the number of rolls needed.

For loose fill material, work out the floor space in square metres - approximately 200 litres of material will be required to cover each square metre to a depth of 200mm.

Safety

• The mineral wool in the insulation can cause irritation in the throat, so a breathing mask should be worn. Also, gloves should be worn to prevent irritation to the hands
• Wear long sleeves and trousers, and try to tuck the sleeves or legs into gloves or socks respectively.
• Use a crawl board between joists, else you risk falling through the ceiling if you misplace a hand or foot.
• Only open packages of insulating material while in the loft, and unroll or pour materials gently, so that fibres do not become airborne.
• Keep the loft hatch closed.
• Wash any clothes worn during installation separately from the normal wash, and dispose of the ventilation mask after use.

Laying Insulation

1. Starting at the eaves, unroll the insulation material towards the centre of the loft. Do not try and stretch the insulation. Ensure that a gap is left at the eaves for ventilation.
2. Feed the insulation underneath any cables or pipes, ensuring that you do not cause the cables to stretch.
3. At the centre of the loft, or any other convenient location, cut the roll using scissors - do not just tear it. Push the edges down beneath the joists.
4. If you have a cold water tank in your loft, do not insulate underneath it. This should be insulated independently.
5. If water pipes run along parallel to the joists, you may need to cut the insulation lengthways. Alternatively, loose-fill insulation may be an easier solution where the location of water pipes pose a problem.
6. With the first piece of insulation laid, move to the opposite side of the loft and roll out another section of insulation so that it meets the first.
7. Repeat until all joists are filled in.
8. Any spare insulation can be attached to the loft hatch cover. You may also want to draught-proof the edges depending on the snugness of the fit.