It could be that your walls are not adequately insulated. The impact of the placement of thermal insulation within the building envelope and insulation interaction with thermally massive components are commonly misunderstood. Thermal Insulation placed towards the outside of the building performs much better if there is significant variability in ambient temperature, referred to as diurnal temperature swing, and even summer to winter variation. Most populated areas in South Africa falls in this group. Placing the insulation towards the outside will result in a big thermal time constant for the wall for heat loss to the outside, in turn resulting in a bigger than expected Reactive R-value.

The solution for this is External Wall Insulation System (EWIS). Also referred to EIFS, Exterior Wall Insulation Finishing System or ETICS, External Thermal Insulation Composite System.

Technopol Southern Africa (Pty) LTD, leading manufacturer of Expanded Polystyrene (LiteCel™ EPS), together with Terraco, provides an Exterior Wall Insulation Finishing System locally. The system comprises an insulation layer, glass fibre matting, undercoat render, primer and final decorative topcoat rendering.

Alternatively, Metal Cladding (LiteClad™) can be applied over the Exterior Insulation Layer with the appropriate Vapour Barrier.

Advantages of Exterior Wall Insulation:

• Limiting heat loss and gain from and to the inside of the building – this reduces the heating costs and CO₂ pollution
• Provide benefits such as noise reduction, water resistivity and weatherproofing
• Provide fire protective cover over the insulation, being expanded polystyrene, mineral wool or other types of thermal Insulation
• Revive the outside appearance of your building to look fresh, functional and modern
• Allow walls to contribute to thermal mass and reduce costs for space heating in winter
• Limits condensation on internal walls
• Does not reduce internal floor area.

The pricing of the external insulation will be higher than that of internal wall insulations, but money shouldn’t be the only motivator. Upgrading your home’s efficiency will drastically improve your property’s carbon footprint. So, if sustainability is at the heart of your renovation, you might see external wall insulation as good value for money.

You’ll get the best result in terms of energy savings if upgrading the efficiency of your walls is part of a wider plan to improve your home’s thermal performance. For instance, exterior wall insulation might be stage one, with plans to add roof insulation.