With ever-soaring energy prices and constant reminders about the need to limit CO2 emissions, none of us one can afford to ignore the importance of insulation. New homes are built to high standards of insulation, but older properties will invariably benefit from work to prevent heat loss, leading to lower fuel bills. Continual product innovations mean it is probably worth considering an upgrade even if your home already has a certain amount of insulation. Summer is a good time to do the work.
Where to start? Heat rises, so the biggest loss of heat is often through the roof. For a building with a pitched roof over loft space, laying a thick blanket of glass fibre or mineral wool is the most effective way to insulate and costs can be recouped in lower energy bills within a year or two. Loose-fill material such as vermiculite is another option, but is not as popular because ideally it needs to be thicker than the depth of the joists – so tends to be used only in an awkwardly shaped loft.
Rolls or slabs of insulation material are generally 600mm wide to match standard joist spacing, so it is a fairly simple job, but it is important to wear gloves and long sleeves to prevent skin irritation and a mask to avoid breathing in fibres. Remember to leave the eaves clear for ventilation and to lift electrical cables over the insulation so they do not overheat. Tie insulation around water tanks in the loft but do not insulate underneath them. Wrap a wad of insulation in plastic and secure to the upperside of the loft hatch.
Once the work is done, all those Christmas decorations and other clutter stored in the attic will no longer be bathed in the heat that used to rise through the ceilings below, but the occupants of everywhere apart from the roof space will be a lot warmer!
Pipework is another major source of heat leakage and pipes are at risk of freezing in the roof space if left unlagged. Foam casings are available in various sizes and are easily fitted around pipes. Just join the pieces of foam with PVC tape. For neat joins at corners, cut the ends at 45° using a mitre board and then tape together. Another method of insulating pipes is to box them in using battens and plywood and pouring in loose-fill insulation material. This has the added advantage of concealing unsightly pipes and if the boxing is decorated it will be effectively disguised. Screw, rather than nail the boxing together so the pipework can still be accessed when necessary.
Walls account for a huge surface area in any home and can be the cause of up to 35% heat loss. Cavity wall insulation involves pumping mineral fibres, foam or pellets into the wall space and is a job for an approved contractor. The pay-back period is about five years. External insulation for solid walls is another area for the professionals, but competent DIYers can tackle the interior of solid walls. An economical solution is to dry-line walls with insulated gypsum board, fastened directly to the wall with panel adhesive or nailed to a supporting framework of treated wood strips. Ordinary plasterboard sheets can also be used, combined with insulation blanket and a vapour barrier.
Mark cutting lines on the dry lining board with a pencil before cutting with a fine-toothed saw, on the opposite side to the insulation. Use a padsaw to cut holes for light switches or socket boxes. When nailing the boards in place, hammer them so the nail heads just dimple the surface.
Floors and windows are other places where insulation and draughtproofing can make a big difference to energy bills and to the comfort of the building’s occupants. We’ll come back to those another day.