Lofty ideas

What is it?

Loft insulation lies between and over ceiling joists in a roof, and acts as a blanket to prevent heat escaping.

2006 building regulations insist on a minimum insulation thickness of 25cm but many houses only have 2.5 - 7.5cm.Topping this up to at least 27cm is recommended.

Can I do it myself?

Yes - unless you opt for the 'blown' method (in which insulating materials are pumped into the roof space by machine).

Alternatively you can get a professional installer to advise you on the best products for your home (see Find out more below).

How much will it cost?

The government estimates the average cost of bringing your loft up to current legislation is £284. This will vary according to materials used, size of your loft and whether or not you do it yourself.

How much cash will I save?

If you already have some insulation that you're topping up, you can expect to save £50 - £80 per year on your energy bills. If you don't have any, the savings could be approx £130 per year.

How much carbon will I save?

410 kg per year for a top-up. Or much more (approx 1.5 tonnes) if you have no loft insulation and install the recommended 27cm thickness.

What materials should I use?

Basic rolls of fibreglass or mineral wool will provide superb insulation for minimal cost (from approx £25 per 10 square metre). The downside is these are very energy-intensive to produce compared to natural alternatives.


L to R: Insulation products: Thermafleece and Warmcel 100.

Two tried and tested green products include:

  • Thermafleece - made from pure British sheep's wool;
  • Excel Warmel 100 - made from 100% recycled paper;

Both are safe and easy to install, and available from the Green Building Store.

Find out more

For advice on grants, savings, and installation, visit the Energy Savings Trust.


This article is based on an extract from Friends of the Earth's book How Can I Stop Climate Change?

Figures correct at time of publication.