Paddy Leighton of Icynene UK explains how new high performance insulation systems can contribute towards combatting climate change
The Committee for Climate Change Report ‘UK Housing: Fit for the Future,’ states that better standards of insulation in new build and existing housing stock is vital if we are to address the problem of reducing carbon emissions in any meaningful way.
According to the report, 14 per cent of total UK CO2 emissions results from energy usage in homes. Also, it says that in 2017, emissions from buildings actually rose by 1 per cent on the previous year.
Retrofitting of traditional insulation materials is a complex, time-consuming and expensive affair, and one which rarely addresses the important issue of air leakage. As up to 40 per cent of a building’s heat loss can be attributed to this (draughts), it is vital that it’s included in any programme of measures designed to improve thermal performance.
Modern spray applied insulation systems do a much better job than rigid board and mineral fibre materials as they are designed to expand rapidly when applied, sealing small gaps, service holes and hard to reach spaces where air leakage generally occurs.
If we go back to basic principles, heat loss occurs through a combination of conduction, convection, radiation and mass transfer. In the UK, the construction industry focuses primarily on U-values as a measure of conductive heat loss.
Open cell, spray applied insulation systems don’t perform as well as some other types of insulation by this U-value measure. However, if you spend any time in mountain environments you know it is the wind that strips the heat from your body, and it is the same in buildings – it doesn’t matter what your U-value is if there are draughts.
Breathable, open cell foams not only insulate from conductive heat loss but also from convective heat loss by controlling that air movement. Furthermore, as spray applied foam insulation is extremely flexible, it moves with the structure, maintaining insulative integrity indefinitely.
Mass transfer is a more complex issue and relates to how much moisture is in the air (humidity). The more moisture there is, the more energy it takes to heat it, so to feel warm, damp buildings need more energy than dryer ones.
Studies have shown that moist, humid air can support up to 4,000 times more heat energy than dry air and, as air leaks out of a building, it carries this moisture vapour and with it, heat.
To control humidity, you need to be able to control the air movement in a building – and this can only be done if the building is relatively airtight. Spray foam insulation does this effectively by helping to create a ‘sealed box’ environment which allows controlled ventilation and mechanical heat recovery systems to perform efficiently.
HIGH PERFORMANCE, BREATHABLE INSULATION
There’s now a new breed of spray-applied insulation system – a flexible open cell material with a soft, yielding texture. This not only provides outstanding insulation properties, but also allows the building to breathe naturally, resisting internal condensation – particularly important when insulating heritage-type buildings. Developed in Canada to cope with their extreme winter temperatures, Icynene FoamLite is one such example.
Systems such as this are installed using a pressurised gun. Foams are applied as a two-component mixture which expands 100-fold within seconds of application, closing off all gaps, service holes and hard to get to spaces that conventional insulation materials fail to reach.
When selecting which spray applied insulation to use, it is important to understand a number of factors: unlike the urethane foams of 20 years ago, modern spray foams use water as the blowing agent. This means that the reaction between the two components produces CO2, causing the foam to expand.
As these expand, the cells of the foam burst and the CO2 is replaced by air. Systems such as Icynene’s have a Global Warming Potential of 1 and an Ozone Depletion Potential of 0 . Neither do they emit and harmful gases or support combustion or add fuel to a fire – a hugely important factor in today’s building industry.
Furthermore, spray-applied insulation saves time on site with the re-occupancy of a building taking as little as two hours. It also boasts acoustic benefits, reducing the transfer of noise through walls and floors.
With over 60 per cent of our current housing stock originating from the pre- 1960s when little thought was given to heat-loss prevention, the challenge facing the UK in its efforts to reduce carbon emissions are considerable.
Better understanding of the causes of heat loss in buildings and the wider use of new, high performance insulation systems will go a way to addressing the problem. The challenge is to get these systems adopted quickly and made to work effectively in both the private and public housing sectors.
Paddy Leighton is director at Icynene UK