Understanding Cavity Wall Insulation Will Help Builders Address Energy Performance Worries Of Property Owners

It’s widely acknowledged that South Africa is facing an energy crisis. In an effort to make buildings more sustainable, the 2011 SANS-10400 regulation will be updated with Part XA, which focuses on energy use in properties.

Here we speak to Suria Ramnarain, Sales Development Manager at Knauf Insulation about how builders can use the new SANS-10400-XA regulation as an opportunity to add value to their projects by adding insulation to cavity walls.

Under the new regulation, each construction element of new buildings and extensions designed for human occupancy must meet a specific R-value – R-values measure how well a material of a specific thickness resists heat flow. However, the R-value may vary depending on the building use or region.

One of the easiest ways to achieve the required R-value on external walls is to add a cavity (an air gap) between an inner and outer skin. The introduction of cavities improves a building’s thermal performance, reducing energy consumption and carbon emissions associated with heating or cooling the internal environment. This in turn results in savings on energy bills for the rest of the building’s life.

While simply adding a cavity to an external wall may meet the requirements of SANS-10400-XA, builders and contractors should be aware that this alone will not meet the changing expectations of property owners. This is because SANS-10400-XA is not the only regulation focusing on energy use in buildings; Energy Performance Certificates (EPCs) will also be introduced and are likely to impact buyer or tenant demand where property specification is concerned.

EPCs will contain information about the energy consumption of buildings in South Africa. As a result, prospective purchasers and tenants of commercial premises will become more sensitive to the expected energy performance, or put another way the annual running cost, of buildings they are looking at.

In the UK, where EPCs are well established, one third of EPC points are awarded to insulation. This is because adding insulation during construction is the most economical way of improving energy efficiency. And, although it is possible to retrofit insulation, it is far more expensive and causes disruption to the tenant or owner. Therefore, adding insulation to properties being built now is by far the most effective way to future proof their value when EPCs become established. It is expected that once EPCs are adopted for commercial premises, they will then be rolled out to domestic properties.

So why is insulation so important? The greatest proportion of energy loss from heating or cooling a property without insulation takes place through its roof and external walls. Adding high performance insulation keeps buildings warm when it’s cold and cool when it’s warm and therefore conserve energy.

Research by the Clay Brick Association and the University of Pretoria has shown that adding a cavity to a property reduces energy consumption by 30%. But maintaining a stable internal temperature by adding insulation to that cavity helps to reduce it by 70% – meaning even lower fuel bills. Where mineral wool is superior to other insulation types is that it is non-combustible. Ceiling Rolls are certified under SANS 10177 parts 5 and 10 A/A1 for fire, and have a Euroclass A1 Reaction to Fire classification. Masonry Cavity Slabs (DriTherm) also have a Euroclass A1 Reaction to Fire classification and gives specifiers added peace of mind thanks to BBA (British Board of Agrément) certification.

Ultimately, a well-insulated building with a good EPC rating is more marketable and mitigates against future rising energy costs, whilst providing more comfortable living and working conditions. And unlike other insulation types, mineral wool gives the added reassurance that it will not contribute to the development or the spread of a fire should it occur. It therefore makes good business sense to install mineral wool insulation into cavities during construction.

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