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  • Guide to Loft Insulation

    Loft Insulation and It’s Importance to Energy Conservation

    According to Brenda Boardman of Oxford University’s Environmental Change Institute, Britain is generally accepted to have the worst insulated houses in western Europe: “The rule of thumb is that we’re about 30 years behind the times.” Partly, she says, that reflects the 21st century’s love of 19th-century homes, which were constructed when people did not expect the whole house to be cosy and bracing draughts were seen as a health feature. New rules require new houses to be much more energy-efficient. However, a low rate of homebuilding means that it will take many decades for these improvements to percolate through the housing stock.

    The current Building Regulations state that the minimum recommended level of loft insulation, in new buildings, should be 200mm ( 8″). If your current insulation is 100mm (4″), or less, you should invest in having it topped up to the 200mm level. As 25% of the heat, you have already paid for, is going through the roof it makes good sense to prevent the loss, save money on the heating bills and enjoy a much warmer comfortable home environment, as well as protecting the exterior environment.

    What you can do to keep heat in

    As much as 20% of your energy bill can be saved by effective loft insulation. Because heat rises, insulating a loft can be especially effective. When insulating a loft, a depth of at least 150mm (6inches) is recommended. In many older properties, shallow joists in lofts restrict depth for loose-fill insulation. It is a quick and easy job to lay the insulation material between the joists. The various methods of loft insulation are summarised below. Whichever method you choose, it is worth remembering that mineral fibre and rock fibre are proofed against rot, vermin and damp. These materials are also non-flammable.

    Blanket Insulation

    Glass fibre, foil-backed felt, rock fibre or mineral fibre blanket insulation is available by roll. These rolls fit snugly between the joists. This is probably the most common type of insulation.

    Rolls are available in 75mm (3inches) and 100mm (4 inches) thickness.
    The width of rolls range from 300mm (1 foot) to 1200mm (4 feet).
    The lengths of the rolls range from 5m (16 feet) to 9.4m (30 feet).

    Granular, loose fill insulation

    Cork granules, exfoliated vermiculite, mineral wool or cellulose fibre are all forms of loose fill insulation. This may not be the best method to use in a very draughty loft space, as the draught can cause the fibre to blow about in high winds.

    However it is easy to apply and is especially useful for areas where joists are irregularly spaced and where pipes or other obstructions make it difficult to lay a blanket insulator.

    Sheet insulation

    If you intend to use the attic area, insulate the sloping surfaces of the roof instead of the floor. Sheet insulation can be fixed between the rafters. Semi rigid batts of mineral fibre or fibre glass tend to give better results than lightweight rolls and only thin sheets are required, especially if the finish is covered with plasterboard.

    Always allow sufficient space between the insulator and the roof slates or tiles to allow for ventilation, and thus avoid condensation.

    Blown fibre insulation

    A professional contractor can be employed to blow fibrous inter joist insulation, via a hose. This may not be the best method to use in a very draughty loft space, as the draught can cause the fibre to blow about in high winds. The contractor should be able to advise you.

    Some useful loft insulation links

    http://www.instagroup.co.uk/ – Roof insulation – Wool insulation products
    http://www.teachmediy.co.uk/ – Knauf DIY
    http://www.est.org.uk – Wickes Home Improvement – Energy Saving Trust profile page

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