Insulation Compulsory In All New Buildings


SANS 10400–XA: ENERGY USAGE IN BUILDINGS is a law which makes it compulsory for all new buildings to be insulated as of November 2011. The law is a result of Eskom’s Demand Side Management (DSM) Plan. Eskom was desperately trying to supply enough electricity to South Africa with limited power sources. Because increasing the supply of electricity (building new power stations) would take years, Eskom attempted to address the imbalance between supply and demand from the demand side.

If thermal ceiling insulation and high-performance window systems were introduced today into all new residential and commercial buildings, an estimated 3500 MW in electricity could be saved by 2020. This is almost twice the electricity currently produced by our only nuclear power plant, Koeberg (1800 MW).

By fitting our homes with insulation, South Africans can take it upon themselves to help prevent the inconvenience of future load-shedding. Through installing THERMGUARD, compliance with SANS 10400-XA will not be a grudge. You will experience improved comfort and power savings, all whilst adding to the resale value of your home.

Architectural Specification

Architects and specifiers are in the perfect position to set the construction sector on a green and sustainable path by actively promoting and insisting on sustainable products, such as Thermguard insulation.

Thermguard should be installed according to the climatic zone as determined by SANS 10400-XA. Installed thickness should range between 100mm and 135mm, providing R-values of 2.5 to 3.38. Water pipes should be lagged with insulation to prevent freezing. Downlights must be isolated according to the manufacturer’s instructions.

Climatic Zones

The roof insulation requirements for SANS 10400-XA are dependent on the climatic zones of South Africa. The thickness of the insulation needed is determined according to which zone your building is located in. Below is a map illustrating the different zones.

The table below shows the requisite R-Values for cellulose fibre according to climatic zone.


1 Cold Interior Johannesburg, Bloemfontein 3.7 90%
2 Temperate Interior Pretoria, Polokwane 3.2 88%
3 Hot Interior Makhado, Nelspruit 2.7 87%
4 Temperate Coastal Cape Town, Port Elizabeth 3.7 90%
5 Sub-Tropical Coastal East London, Durban, Richards Bay 2.7 87%
6 Arid Interior Upington, Kimberly 3.5 89%

Note: The R-Values shown above do not take into account the insulating properties of the roofing materials. Hence the actual R-Value of building insulation required will be less than that shown in the table, depending on your roof design.

Working Out Required Thickness:
Example for a typical building in Zone 1

Total R-Value Required in Zone 1:                                                                                 3.7

The average R-Value of a normal roof structure:                                                       0.35

Therefore added insulation R-Value required = (3.7-0.35)                                        3.35

The formula to calculate the thickness of Thermguard required is:

Required R-Value x Thermal Conductivity of Thermguard (0.040)

= 3.35 x 0.040

= 0.134m

= 134mm of Thermguard

If the roof has Reflective Foil (Sisalation)

R-Value of Reflective Foil                                                                                                0.75

Therefore added insulation R-Value required = (3.7 – 0.35 – 0.75) 2.6

Required R-Value x Thermal Conductivity of Thermguard (0.040)

= 2.6 x 0.040

= 0.104m

= 104mm of Thermguard

Obviously roof structures differ so contact your nearest installer for expert advice on the thickness required for your home.
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