Insulating Your Loft

There has never a better time to think about insulating your loft. If you want to save money this winter and reduce your carbon footprint at the same time, it's the first place you should look at. For relatively little money you can make significant improvements, especially if you're willing to get up in the loft and tackle the job yourself.

Government grants for insulation are available for all homeowners, and for those renting. See www.direct.gov.uk for more details.

How much can I save?

Up to 25% of your heating costs may be lost through poor loft insulation, so on a typical £450 heating bill, you could be saving £112 every year by properly insulating your loft.

How much will it cost me?

Let's take a typical Victorian Terraced house as an example. Such a house might be 3.6m wide by 10m long. This would have a loft area of 36m2. Wickes for example offer "Easy Lay" loft insulation at £5.35 a square meter. Assuming that it's the right size for our joists, and that we'd have a 20% loss due to offcuts, the total cost would be £231.12. If we happen to find a good deal on insulation, say, a 2 for 1 offer on insulation rolls, then this job could easily pay for itself in reduced heating bills in the first year.

Don't forget to ask your local authority if grants are available!

Types of Loft Insulation

Fiberglass and Mineral Wool Rolls

Normal glass fibre or mineral wool insulation is very itchy to handle, as the glass fibres tend to get everywhere. You should always where gloves and a mask when fitting. Apart from the itchiness, it's very easy to fit - you simply roll it out between the joists in the loft.

The thicker the insulation layer, the more effective it is. In the UK it is recommended that the total thickness of this type of insulation should be 270mm, but older installations tend to have less. If you already have some but not enough, there's no point in removing the old stuff first. Simple roll the new stuff on top of the old insulation layer.

Space blanket insulation is covered in a polythene film, which means less of the itchy glass fibre everywhere. It's more expensive but much more pleasant to use, especially in tight spaces such as this small annex loft space.


Space blanket

Loose Fill

Loose fill insulation materials can be blown or poured into the cavities between the joists. The depth of the fill should be about 270mm (like glass fibre insulation roles). Often the joists are less than this depth, so they'll have to be made up to at least this before you can start.

DIY filling materials, such as vermiculite and mineral fibre can be bought in bags for the purpose. Proffesionals might use a machine to blow the insulation into the loft space, but the principle is the same.

Going Green

There are three common types of "Green" insulation: Sheep’s wool is often the most expensive, as you'd imagine. Recycled newspaper is a very good option. It really is fire retardant, and is not itchy like fiberglass. Recycled plastic "wool" is made from recycled plastic bottles, and resembles glass fiber, but is also wonderfully itch free.

"Green" insulation products are only just coming into the high street DIY stores, and are well worth looking out for!

’Glass wool’ or fibreglass rolls can also be made out of a high proportion of recycled glass.

Dos and Don’ts

Be careful!
Plasterboard will not take your weight, so be careful you don’t put your foot through it!