Understanding insulation

“Insulation has played a vital part in the evolution of buildings and is increasingly important, especially as we see a rise in global energy prices,” says Mark Gillott, development director at Knauf Insulation.

There’s an increased interest in sustainability in the construction sector, with various organisations, such as Excellence in Design for Greater Efficiencies (EDGE) and the Green Building Council of South Africa (GBCSA), highlighting the impact a green building has on the planet and its residents. Over the years, we have seen regulations that standardise adding green aspects to a project.

“The building code pertaining to energy efficiencies and sustainability came into effect in 2011, this standard is the SANS 10400XA. The purpose of this standard is to drive sustainability and energy efficiencies,” says Lyle Jeffery, national sales manager, Lambdaboard. He adds that the code came into effect during the peak of the Eskom load shedding crisis.

Defining insulation

“There’s so much more to insulation than simply managing the internal environment by controlling factors such as penetrating heat, or cold gain and loss,” says Gillott. This is unfortunately, a little-known fact in industry. This was seen and is recalled by Jeffery during the construction of RDP housing.

“The standard RDP house was badly build with no ceiling or insulation at all.” Problems that this created included condensation developing on the galvanised steel roof.

“And in turn started dripping continuously on the inhabitants or home owners in the early hours of the morning once the condensation had built up. Energy costs per household is also an issue due to heat loss / gain – brought about by a poorly insulated building,” he explains.

Inefficiencies surrounding poor workmanship and inferior materials were addressed. “The grant from government is increased, and workmanship issues have been largely resolved. With SANS 10400XA finally in play, it means that that insulation is now a legal requirement in the building code. Each building therefore needs to comply with a certain R-Value as stipulated in the ‘Deemed to Satisfy’ part of the SANS 10400XA code. This therefore allows a ceiling and insulation product,” Jeffery says.

According to Gillott, insulation is the most cost-effective way to target energy savings and therefore offers users the quickest payback.

Insulation and energy efficiency

SANS10400XA codes regulate the installation of insulation in buildings. Image: Pixabay

The energy saving properties of insulation mean buildings are kept warm in the winter and cool in the summer. The bigger the temperature difference between the inside and outside of a building, the faster the building will lose cold or heat.

“Mineral wool insulation helps to maintain the inside managed temperature (from heating or air conditioning) by slowing heat / chilled transfer by convection, conduction and radiation,” says Gillott.

Living conditions in properties without outside energy source for heating or cooling can be improved using insulation. “By insulating a property properly, you can slow down the rate at which the sun heats your living environment during the day and reduce the rate at which the day’s residual heat dissipates from your property in the evening,” he says.

Gillott advises a whole-house approach to energy efficiency. This of course refers to new build projects. Retrofits, buildings being converted, refurbished or renovated can also fit insulation. “There are many methods to retrospectively fit insulation to existing or older buildings,” Gillott shares.

Having an insulation expert is valuable to advise on how to use insulation to reduce the reliance on appliances such as geyser timers or blankets, gas heaters, underfloor heating, air conditioning, heat pumps and solar systems.

Selecting insulation

“It’s critical to make your first-choice count. If you do, your insulation should not only offer excellent thermal performance (along with energy saving, cost saving and combating climate change) but also deliver superior acoustic and fire safety properties, enhance quality of life and ultimately raise the overall performance of the building in which it is installed,” Gillott says.

According to Jeffery, a plaster board with fibrous insulation is most commonly used. “The thickness of the insulating material is dependent on the ‘deemed to satisfy standard’ as a guideline in the code. The other alternatives are cellulous fibre that is pumped into the ceiling void, that lies lose on top of the ceiling or an insulated rigid ceiling.” The rigid insulated ceiling has several advantages over conventional systems thanks to the Long Term Thermal Resistance (LTTR) of the Lambdaboard.

With insulated dwellings, the inhabitants can take control of the energy costs as the heat generated in the homes does not escape through the ceiling voids. “A further facet of SANS 10400XA is the sustainability aspect, Insulation products must meet the appropriate green credentials, certification or compliance with the relevant controlling bodies also ensures that the overall carbon footprint is reduced,” adds Jeffery.

Insulated masonry cavity walls

Insulated masonry cavity walls offer excellent thermal performance when the cavity is used as an insulation zone. “The cavity wall benefits from several features that account for its popularity with designers, developers and home owners,” says Gillott.

Benefits of an insulated masonry cavity wall

• Design flexibility to meet the energy performance requirements of clients with widely available materials.
• In a heated or cooled environment insulation reduces energy consumption and pays for itself.
• Suitability for traditional methods of construction.
• Existing empty cavities (minimum 40mm) can be upgraded with retrofit solutions.

“The greatest proportion of heat loss from a typical house is through the roof and walls. Installing masonry cavity walls slows down the rate of heat / chilled loss (in a controlled environment) therefore provides immediate savings on fuel bills,” adds Gillott.

Energy Performance Certificates (EPCs)

According to Gillott, South Africa is expected see the introduction of Energy Performance Certificates (EPCs). “EPCs tell you how energy efficient a building is and provide you with a rating from very efficient to inefficient. They give an indication on how costly a building will be to heat, cool and light and what its carbon dioxide emissions are likely to be,” he elaborates.

EPCs provide more information about:

• Loft insulation
• Wall construction and insulation
• Age of construction
• Glazing
• Fuel type
• Boiler make and mode

In the UK, EPCs are in full effect, buildings on the market must have the certificate. Gillott shares that the energy performance survey that is carried out highlights the ways building owners can save money on their energy bills and improve the comfort of their home or commercial property.

“The EPC also identifies what the energy efficiency rating will be if improvements are made and highlights cost-effective ways to achieve a better rating,” he concludes.

Benefits of insulation

• Save money on energy bills;
• Reduce general energy use and lower greenhouse gas emissions;
• Reduce the use of heating and cooling systems;
• Improve the overall comfort in living and working environments;
• Help prevent additional maintenance over the lifetime of a property; and
• Assist from an acoustic and additional health point of view (minimising the threat of mould and damp).

Statistics show that a staggering 42% of energy input (for heating or cooling) is lost through a roof or ceiling, with 24% lost through external walls.

Source: Knauf Insulation