Natural Fibre & Recycle Insulation Products

Properties of Natural Fibre Insulations 

  • Low Chemical Content compared to synthetic insulations and VOC-free meaning healthy internal spaces

  • Fire Resistance better performance than synthetic materials, with no off-gassing

  • Hygroscopic and Breathable - offering excellent indoor air quality and regulated humidity.

  • Low or zero-embodied carbon made from carbon-sequestering plant fibres and/or recycled waste.

  • Flexibility suitable for domestic or commercial new build and retrofit projects

  • More Readily Recyclable or reusable at the end of life compared to synthetic insulation.

  • New Build Approved often BBA/LABC certified

  • English Heritage Approved often used in traditional and listed buildings

Uses in Construction

It is important to compare different products carefully to choose the most suitable one for your project, and consider available LCA (Life Cycle Analysis of whole life carbon) and EPD (Environmental Product Declaration) data for different products, to ensure that the product provides a truly low-chemical, low-embodied carbon solution for your building.

Natural insulations, as outlined above, can be detailed as a sustainable alternative to conventional synthetic insulations in every typical insulation application. Warm and cold roof insulation, timber frame insulation, internal and external solid wall insulation, insulated floors, etc. in new build or retrofit. Foamed glass and cork are the only natural insulations rot- resistant enough to be detailed at or below external ground level.

Because these insulations are vapour permeable, care must be taken to detail them correctly (especially in internal solid wall insulation and warm roof build ups) to ensure that condensation issues do not occur as moisture vapour leaves the thermal envelope. Manufacturers of natural insulation (or NBUK experts) can provide advice on this.

Materials and Process

Natural insulation products provide a sustainable, healthy alternative to conventional synthetic materials, and are produced from a range of renewable or recycled raw materials.

These include; Sheep wool (as soft insulation quilt rolls or batts for typical applications in lofts, roofs or between timber studs); Recycled timber (either as soft batts for typical applications, or solid insulation boards – square edge or T&G - for internal and external timber frame or solid walls insulation, or over rafters); Cork (as solid insulation boards - internal or external -, as granulated loose fill for cavities, and mixed with lime in insulating plasters and screeds); Hemp fibre (in soft quilts or batts); Recycled cellulose - paper - (as a loose fill insulation which can be blown – wet or dry – into cavities to insulate timber frames (e.g. as roof insulation or insulation between studs); Recycled cotton (as quilt insulation for typical applications); Recycled glass (foamed, as a partially load-bearing perimeter insulation block, or a gravel which provides a non-wicking, insulating sub-base for breathable floors).

The raw materials described above are made into insulation products using a variety of proprietary processes. Factories which produce these insulations are sometimes located in the UK, but more often in other European countries. For many of the products described above, different brands are available; with minor differences in technical specification and production processes. As lightweight insulations, most are chemically treated for fire resistance and pest resistance, and most will use either a glue (boards) or recycled polyester (quilts/batts) as a binder.

For Specifiers

Thickness for thickness, natural products may have less insulation than (is claimed by!) some synthetic alternatives, but overall they tend to perform better. Their breathable, hygroscopic nature means they keep their shape over time in the presence of moisture - meaning better thermal performance over the long term. Add to this a better fire resistance, no chemical off-gassing, passive humidity regulation and healthy indoor air quality, and it’s easy to see why more and more people are choosing natural insulation products.