Glass / Mineral Wool

Mineral wools are fibres made from minerals or meal oxides. They have insulating and sound-reducing properties due to their ability to hold air within their structure. They are also fire-retardants. They can irritate eyes, skin and respiratory tract, and may be carcinogenic.

Glass mineral wool is typically made from recycled glass, and toxins produced during manufacturing are very low. It can itself be recycled.

This is one of the cheapest options.

XPS (Extruded Polystyrene)

Is made from styrene, a toxin – can be dangerous when burned. Benzene, a known carcinogen, is used in the manufacturing process.

Polyurethane

Polyurethane is extremely flammable, and releases toxic gases when burned.

Cellulose

Cellulose insulation is made from recycled paper, and is environmentally preferable. It can absorb moisture which can lead to mildew, so it is best not used in damp environments.

One such product is Warmcel made by Excel Industries

Foamed Glass

Usually made from recycled glass, but can be expensive.

Wool

Becoming more widely available, but can be expensive. Has many excellent natural properties.

You can obtain it from Second Nature UK , who manufacture Thermafleece

Cork

Insulation can also be made from recycled cork.