Why is thermal insulation important?

As leaders in the roofing industry, we at LCP Roofing, believe that it is important to keep up to date with all industry regulations. It is equally important for any of our current or potential clients to understand roofing regulations that may impact on the protective roofing structure of their homes.

In the designing and erecting of roofs, many factors need to be taken into consideration. Thermal insulation is considered to be an important factor, even though it may only represent a small section of the building process.

According to the Thermal Insulation Association of Southern Africa (TIASA), South Africa has been divided into six climatic regions, as shown in the image below.

Map of climatic zones in South Africa

Map of climatic zones in South Africa.

While each of the six zones has different heating and cooling needs, the principles for energy efficient design are similar. The recommendations for the correct ‘R-value’, as specified in SANS 10400-XA for heat flow direction, are dependent on the climatic conditions occurring in the particular climatic zones.

Energy efficiency standards are applied to lower peak electricity demand. Thermal insulation plays an essential part in the efficient design of homes. Other considerations to bear in mind when designing a roof include the orientation of the building, shading and window design.

It is important to remember that roofs are exposed to both high solar radiant heat increases in summer and high heat losses during winter nights. It is for this reason that the roof-ceiling combination deserves special attention from a thermal point of view. Design factors for thermal resistance and conductivity are considered to lessen the loss of energy, but additional deemed-to-satisfy thicknesses of insulation products help in promoting the environmental benefits of energy saving.

In accordance with SANS 204 energy efficiency in buildings, insulation installation shall comply with minimum required ‘R-values’ as listed in Table 1 below:


The direction of heat flow in Table 1 is considered to be the main direction of heat flow for the hours of occupation of the building. This takes into consideration the higher rate of occupancy of houses during the night, rather than during the day.

Where a downwards direction is listed, this indicates that summer heat is flowing into the building and this is a major concern. A combined downwards and upwards requirement means that summer and winter (i.e. heating and cooling) have a roughly similar level of energy use. The upward flow direction shows heat loss from the building during winter, and this is also a major concern.

When selecting insulation for your roofing projects, the abovementioned aspects are important to bear in mind, not just for compliance, but also for efficiency of design. Another factor to consider in the selection process is fire performance, with which TIASA can assist, as they have extensive compliance information that explains the SANS 10400 requirements.

In summary, thermal insulation for any roofing project should not be taken lightly, and there is also an array of different standards to consider.

For further information please contact:

The Thermal Insulation Association of Southern Africa (TIASA)

Tell: (011) 805 5002

Website: www.tiasa.org.za

Article composed by Tamarin Botha, LCP Roofing Sheeting Estimator.