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Insulating hard-to-treat homes

Question: We live in a Victorian semi detached house which we bought in October 2009. It wasn’t insulated well when we moved in and our heating bill tripled over the first winter 2009/10. We then tried to save on heating last winter 2010/11 and only switched on the heating a couple of hours a day, this meant the house was extremely cold most of the time. The loft has recently been insulated.

We also have a few new windows and a new back door, reducing lots of draughts. A lot of windows have now thermal curtains and a lot of doors have draught excluders in front of them. We are unable to get a grant for wall insulation as the cavity space  is too small and the government only funds newer houses with more wall cavity.

Have you got any ideas or suggestions how to insulate this house more? Another winter like this would be very hard to cope with.

ANSWER: In the first instance, stopping draughts would be the most cost-effective and easiest step you can take. In particular you should pay attention to the ground floor – especially if suspended timber. Air movement does not occur through plastered walls but might well occur around the floor joists as they enter the brick walls. There will always be cracks caused by differential thermal movement of different materials such as timber and masonry. Typical weak points include: ill-fitting skirtings; loose floorboards; gaps between the timber linings/ architraves and wall plaster; and ill-fitting loft hatches. Flexible mastic and construction foams are useful materials for filling gaps. You could also look at overboarding loose floor boarding with plywood or hardboard.

If the ground floor is of a suspended timber construction and is accessible from underneath, carefully fitted fibrous insulation is very cost effective (see also our advice on insulating timber floors).

If windows and doors need replacing think about triple glazing as it is not a lot more expensive than double. Internal lining of external walls with insulating boarding – is probably the next element to look at – but of course it will cause more expense and disruption.

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