Loft insulation

As energy costs rise, it’s never been more important to think about insulating your loft, or topping up existing insulation. Loft insulation will effectively reduce heat loss for at least 40 years – and will pay for itself many times over in that period.

Can your loft be insulated?

If your home has an accessible loft with no damp or condensation problems, then it should be a perfect candidate for loft insulation and even if your loft is insulated already, this insulation might need topping up. The recommended depth of loft insulation is at least 270mm. Installing 270mm of insulation in a loft with no insulation will save around 1,000kg of CO2 and £205 per year. If there was already 50mm of insulation and you topped this up to 270mm, the extra saving would be 250kg of CO2 and £60 per year.

Any problems with damp or condensation should be sorted out by an expert in advance. As insulation stops heat from escaping, it will actually make your loft space cooler, which could make existing damp or condensation problems worse.

How are lofts insulated?

There are four main types of loft insulation: mineral wool, natural wool, blown mineral wool and blown cellulose. The former two can be installed as quilts and the latter two are blown into the loft as loose material: a great solution for less accessible spaces.

While blown insulation should only be installed by an installer with specialist equipment, insulation quilts are suitable for competent DIY-ers to work with. Protective clothing, gloves and masks should always be worn when working with loft insulation.

Typically, quilts are laid down between the joists – the, horizontal beams that make up the ‘floor’ of the loft – then another layer of insulation is ‘cross-laid’ to cover the joists.

Remember: this needs to be done to a high standard to avoid unnecessary wastage of heat, so always consult a DIY manual first. And if you don’t feel sufficiently confident that you can do it yourself, please call an installer.

If the loft is going to be used for storage then you can insulate between the joists and use board backed with further insulation over the top – or raise the level of the floor and insulate to the recommended depth.

What could you save?*

  New loft insulation
(270mm thick)
Topped up loft insulation
(from 50mm to 270mm)
Total cost of professional installation Around £250 Around £250
Saving per year Around £205 Around £60
Pays for itself in Just over 1 year Around 4 years
Total cost of DIY installation Around £300 Around £200
Pays for itself in From 2 years 4 years
CO2 saved per year Around 1,000kg Around 300kg

*Estimated figures for a gas-heated, semi-detached home with three bedrooms.

Remember your pipes

Always insulate your pipes, water tank and loft hatch, too. Insulating between the joists of your loft will keep your house warmer but make the roof space above colder. Without their own insulation, pipes and tanks are more likely to freeze; an un-insulated loft hatch could let cold draughts into your house, too.

Could you get help with insulation costs?

You could indeed. There are lots of grants and offers available to help pay for wall and loft insulation. To see what’s on offer in your area please contact us.