WHAT IS R VALUE?
The R-value is a measure of a material’s resistance to heat transfer. The higher the R-value the higher the level of insulation. The BCA sets out minimum requirements for the R-values of materials used in the construction of buildings.
See http://www.yourhome.gov.au/passive-design/insulation for more information.
R VALUES OF HEMP LIME CONSTRUCTION
WHAT IS THE RECOMMENDED R VALUE IN YOUR REGION?
MINIMUM R VALUES TO COMPLY WITH BUILDING CODE OF AUSTRALIA REQUIREMENTS
Hemp lime construction offers a range of solutions to building construction, but of greatest interest to anyone choosing to specify this material is its thermal performance. Currently, in Australia, the insulation or R-value is the major measure of thermal performance. However, there are a number of reasons why buildings built with a hemp-lime composite can perform significantly better thermally than conventional construction.
As well as insulating effectively, hemp-lime materials can absorb moisture and they allow water vapour to move through the building fabric. This makes them very effective in mitigating humidity in buildings.
A number of studies report on the thermal mass aspects of hemp-lime construction and notably its good thermal storage capacity. This dampens diurnal temperature variation and improves indoor temperature stability, (Bevan R & Woolley 2008),(Evrard et al., 2006).
A full understanding of thermal performance in buildings will rely on further scientific research which is underway. This scientific work involves a different approach to building science that will take account of thermal resistance, thermal capacity and mass, heat emissions from materials, moisture absorption and diffusion and other factors.
Using hemp lime for your home will help to:
- keep the warmth inside your home in winter
- prevent heat from entering your home in summer
- reduce your need for heating and cooling appliances
- reduce your heating and cooling related costs and greenhouse gas emissions.
|Typical heat gain in summer for an uninsulated
home (Source: yourhome.gov.au)