WHY INSULATION MATTERS

A recent study highlights the contribution better insulation can make to slowing the effects of global warming. Icynene takes a look

According to a recent study by the Intergovernmental Panel on Climate Change, rapid and significant changes need to be made across the board to combat global warming — including in our new and existing homes.

Unfortunately, there is a common misconception that, to reduce heat loss in a building you simply put more insulation in the roof. This works up to a point, beyond which adding more layers of insulation follows the law of diminishing returns.

Preventing air leakage

In winter, in a typical home, heat flows directly from all heated living spaces to adjacent unheated roof voids, garages, cellars and particularly to the outdoors. In the UK, U values measure the insulation’s ability to limit this heat flow — the lower the U value, the better the resistance to heat loss.

However, up to 40% of a building’s heat loss can be through air leakage, or draughts. Therefore, the best way to increase the energy efficiency of a building is not merely to reduce U values as required by Building Regs, but to combine this with an air barrier — creating a ‘sealed box’ effect to reduce air (and heat) leakage to a minimum*.

Traditional forms of insulation (such as mineral fibre and rigid-board type materials) are relatively inefficient in sealing the box. Nor can they cope with small structural movements which often lead to air-leakage gaps.this can lead to cold bridging and thermal by-pass, which can lead to localised condensation and inevitable dampness.

Spray applied insulation

The modern alternative is a fully breathable, opencell spray foam insulation, which is applied using a pressurised gun system. Foams are applied as a twocomponent mixture forming a foam that expands 100-fold within seconds of application, sealing all gaps, service holes and hard to reach spaces, virtually eliminating cold bridging and air leakage.

Unlike the urethane foams of 20 years ago, modern spray foams such as Icynene Foamlite use water as the blowing agent. This means that the reaction between the two components produces C02 which causes the foam to expand. As Foamlite expands, the cells of the foam burst and the CO2 is replaced by air. From an environmental perspective, Icynene has a Global Warming Potential of 1 and an Ozone Depletion Potential of Zero. Nor does Icynene emit harmful gases once cured.

Modern spray foam systems also have an ‘open cell’ composition. Open cell foams such as Foamlite are extremely vapour open and will allow moisture vapour to pass freely through it, allowing the building to breathe naturally. Open cell foam will also not soak up or ‘wick’ water.

This new generation of spray-applied insulation products, when professionally applied by experienced contractors, can result in near zero air leakage through the building envelope. In fact, Icynene has been shown to achieve airtightness standards exceeding those of the Passivhaus system of construction.

If you’d like to include Icynene spray foam insulation in your project, and want to find out more, visit www.uksprayfoam.co.uk or email the company at info@icynene.co.uk.