Insulation derived from naturally occuring materials
Introduction
Insulation derived from naturally occuring materials can make an attractive alternative to the more traditional fibre glass/mineral wool approach. As well as their excellent heat insulation properties they are generally safe to handle, which makes them much easier to install in ceiling and loft spaces.
These materials are often rated by their embodied energy, or the degree of energy conservation as an insulator vs. the energy used in their manufacture. The lower the embodied energy the greater the positive effect to the environment.
Unlike organic materials though, natural insulators require some considerable energy to produce which means that they have a high embodied energy count. Also the raw materials are usually obtained through open cast mining which causes considerable degradation to the landscape.
All of these products can make effective insulators, however their application can be limited by the depth of material needed to provide adequate insulation.
Foamed glass slab
Foamglass is a long lasting material with an inherent resistance to moisture, air movement and rot. Made from 2/3 recycled glass, it is resistant to fire, water and is also reasonable resistant to compression, making it ideal for loft spaces. The downside to this product is the amount of energy required to produce it.
- Reclaimable
- Contains 2/3 recycled glass
- Fireproof
- High thermal mass
- Hydrophobic
- Resistant to insect attack
- High embodied energy
- Raw materials derived from open mines
- Requires bitumen or synthetic adhesives to install
- Sulphur Dioxide and Nitrogen Dioxide released during manufacture
Perlite beads
Made from volcanic glass which is expanded through heating, with natural fire and water resistant qualities, perlite is a viable alternative to expanded polystyrene for cavity wall applications. As with foamglass, the major downside is the energy required to produce it.
- Reclaimable
- Relatively high natural content
- Safe to handle and install
- Fire and moisture resistant
- Can be used as an aggregate to insulate concrete
- Relatively high embodied energy
- Non-rewable source
- Raw materials obtained through mining
- Must be installed in sealed spaces
Exfoliated vermiculite
Incredibly similar product to perlite, with all the same pros and cons.
- Note: Vermiculite manufactured in the US prior to 1990 contains asbestos.
- Reclaimable
- Relatively high natural content
- Safe to handle and install
- Fire and moisture resistant
- Can be used as an aggregate to insulate concrete
- Relatively high embodied energy
- Non-rewable source
- Raw materials obtained through mining
- Must be installed in sealed spaces
Expanded clay aggregate
With very similar properties to both perlite and vermiculite, raw clay is fired to produced an aggregate material. This does mean however that the embodied energy count is high due to the firing process.
- Reclaimable
- High natural content
- Safe to handle and install
- Naturally non-flammable
- High embodied energy
- Raw material is produced though open mining
Further information and useful links
- Find a Insulation Installer near you
- National Insulation Association
- Energy Savings Trust (est.org.uk)
- Cavity Insulation Guarantee Agency (ciga.co.uk)
- Party Wall Guidance (rics.org)
- Impact of the Party Wall Act 1996 (communities.gov.uk)
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