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Making the right choices over insulation

From landlords renovating an existing large property to self-builders constructing a modest little house all of their own, the benefits of good insulation are becoming increasingly well known.

As well as keeping a home warm and ensuring energy bills can be kept down, well-insulated homes emit less heat and thus are better for the environment. Indeed, the need to make homes more energy-efficient this way was highlighted this week by a World Wide Fund for Nature report arguing that Britain is lagging behind in this regard and needs to do more to insulate homes.

On top of all this, private landlords will need to be aware that, apart from exceptions such as some listed buildings, they will not be able to rent out homes with an energy performance rating worse than an E from April next year. 

However, while appreciating the need for insulation is one thing, the choice of materials is another. 

The use of organic materials is something that many will advocate, on the basis that this is a very 'green' option. Among these is sheep's wool, which is not only by nature a strong natural insulator and water resistant, but also provides another potential market for Britain's hill farmers.

However, the notion that sheep's wool is an ideal choice ignores the potential problems that can come with an organic material, particularly one from an animal. Both when worn by the sheep and after it has been sheared, wool offers a cosy environment for all kinds of bugs, some of which may resist the insecticides and other treatments used to cause an infestation.

This is exactly the calamity that has befallen a family from Northern Ireland. 

In 2011, the Cappell family from County Londonderry set about building their own home. They chose wool insulation as a means of keeping it warm in the greenest and most organic way possible.

However, it transpired that the insecticide the wool was treated with - pyrethrin - was ineffective in killing off moths and their eggs. Although there seemed no problem when they took up residence in the home in 2012, over time the moths became more and more of a feature. By last year, Valerie Cappell told the Daily Telegraph, the infestation had become a "biblical plague". 

The only solution was to tear apart the walls the family had built and remove the wool, replacing it with synthetic insulation. 

She told the paper: "It was soul-destroying and incredibly stressful when we couldn’t work out where all the moths were coming from.

"I think our situation could be the tip of an iceberg - many more people must have installed this kind of insulation."

Indeed, a study of the wool by Rentokil confirmed that the pyrethrin treatment had not worked, and suggested that others who had bought the wool from the same supplier might have suffered similar problems, or will in due course. Most galling of all, the company from which the Cappells bought the insulation has since gone bust, so there is no chance to seek compensation.  

The unfortunate case of the Cappells is bad enough. But if there is a similar problem with insulation in a large building with multiple homes, the scale of the calamity will be multiplied. 

Of course, organic insulation will not always produce a problem and wool is not the only sort. However, it does go to show that whenever insulation is being fitted to a building, it is important to give due consideration to the problems that may arise, as well as the implications for insurance cover in case anything does go wrong with it.