How to Insulate Roofs and Pipework
Good insulation reduces the rate at which expensive domestic heat escapes through the fabric of your home and helps to protect vulnerable plumbing systems from damage. The different parts of your home can be insulated by various methods, and most jobs can be handled by a competent person.
Roofs and plumbing
As with any do-it-yourself job, breaking the whole project down into manageable parts can help. Around 25 per cent of heat escapes through the roof, so it is a good place to start your insulation project. The roof is where pipework is at greatest risk of freezing, so this must be tackled as well.
Invest in protective clothing. A basic kit should comprise:
- Well-fitting overalls and gloves to keep out dust particles.
- Protective goggles and face mask.
- A safety helmet, which is essential when working in confined spaces with limited headroom.
Most important of all, remember that unless you have laid suitable flooring in the roof area, you will only be able to walk on the joists. In between will be the exposed ceiling of the rooms below, which will be fragile and will not bear your weight.
A simple way to stop heat loss is to place insulation material between the joists. Your choice may be influenced by personal preference or ease of use – some varieties are much cleaner and less likely to cause skin irritation than others – or the decision may be made for you by the local authority if you are applying for a grant to complete the work.
Current recommendations suggest that the insulation should be laid to a depth of 200mm. However, this may not be possible with some materials if the joists are of a shallower depth. Also, if the roof area has a floor, this may restrict the depth of the insulation. In the latter case, the floor will have to be lifted to put insulation between the joists.
This is sold by the bag and is simply poured between the joists and levelled off with their top surfaces. Although easy to handle and spread, the dustier varieties, such as vermiculite, can be unpleasant to work with. Moreover, the material may be blown about if the roof area is prone to draughts.
This consists of rolls of glass fibre, mineral fibre or rock fibre, which are simply unrolled between the joists. Widths are available to match common joist spacings. A typical roll length would be 6-8m (20-26ft), but short lengths are also available, known as batts. Some types may cause skin irritation, so always wear gloves when laying the insulation.
These products are light and easy to handle, but as with the blanket versions some types may cause skin irritation. Again, the slab widths match common joist spacings. Look out for high-density slabs if you want the bonus of an effective sound barrier.
Good insulation need not mean great expenditure. The most effective items are relatively cheap and could save you a great deal in the long term. Any water storage tanks in the roof must be insulated to protect them from freezing; indeed, some water suppliers may require this by law. Padded jackets are available for the purpose. Likewise, any exposed pipework in the roof should be fitted with thick insulating sleeves to prevent freezing.
- Leave the space under a cold-water storage tank free from insulation. Warmth rises from rooms underneath to help prevent freezing.
- Insulate the roof access hatch with blanket insulation, backed with plastic, and glue or pin in place.