INSULATION
THE HOLISTIC APPROACH TO THERMAL EFFICIENCY
With the introduction this summer of a new specification governing retrofit processes to improve thermal efficiency, merchants may have noticed more enquiries from installers for insulation products.
T
he new standard PAS 2035: 2019 which came into effect on June 30, specifies a more holistic approach to retrofitting domestic dwellings. As more than 25% of the UK’s houses are more than 100 years old, improving insulation is a pretty crucial element in enabling us to reduce our carbon emissions nationwide. Indeed, did you know we have one of the oldest housing stocks in the world? PAS 2035 is a guide for all government supported projects including those under the Energy Company Obligation ECO. But it can be used on a voluntary basis for private homes outside these schemes.
According to Thomas Wiedmer, technical director UK & Ireland and insulation specialist Actis, the standard champions a matrix approach in which each individual measure is examined in the context of the whole house. This, he says, is because one action might have unintended consequences elsewhere in the property. It is important to look at each case on an individual basis.
“Combined with forthcoming changes in Building Regulations, which will probably come into force in 2020 and are expected to impose more stringent energy efficiency targets, PAS 2035 provides a good framework for reaching carbon emission goals.
“One of the unintended consequences which could occur if not looking at the house in its entirety is the appearance of moisture or condensation” Wiedmer says.
Unintended consequences He adds that, for example, while on the surface it may seem sensible to insulate all external walls to the best possible U-value, this could have unintended consequences elsewhere. Where the ceiling joists meet the walls, in some scenarios, can create a weak thermal bridge. This might lead to moisture build-up and mould growth so it may, counterintuitively,
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be better to use less rather than more insulation.
PAS 2035 talks about Concentrating on the interfaces” which is the right approach. It acknowledges that retrofit projects often go wrong because of poor attention to the corners, junctions and edges of building elements (where insulation and air barriers should be continuous) and the interfaces between the building fabric, the building services and the occupants.
Strategy
“The matrix approach will also highlight, for example, if a revised ventilation strategy needs to be in place when an airtight envelope is created to avoid problems with condensation and mould.
“It’s important to adopt a “Fabric first”
approach, which is both technically sound and usually cost-effective” Wiedmar says. “ It makes sense to ensure that the existing building fabric is as energy efficient as possible before spending resources on other measures. Insulation is generally among the most cost effective and long-lasting, and thus the best investment and also reduces heating costs.” The Actis Hybrid range tackles U-values, thermal bridging and airtightness. Wiedmar says tht as the products are flexible and can bend round corners and be gently moulded into gaps, they are excellent at creating a thermal envelope, free of gaps through which heat could otherwise escape.
“The membranes – insulating vapour control layer H Control Hybrid and insulating breather membrane Boost R Hybrid and Boost R Hybrid Roof - massively reduce the risk of interstitial condensation, guarantee air tightness and can protect the building from precipitation and wind driven rain if installed correctly” he continues.
“It is important that whatever measures are proposed that these are detailed appropriately for the existing pathology of the building, and heritage buildings need particular attention and detailing.”
Training
Actis has also produced a range of educational tools aimed at helping merchants - as well as builders, specifiers, architects and building control officers - understand how its products can help. These include a CPD training module, bitesize how to videos on the website and YouTube, point of sale and downloadable how to booklets and its popular online U-value simulator. Actis also offers free tailored training courses aimed specifically at merchants – on a regional or company wide basis. BMJ
www.buildersmerchantsjournal.net September 2019
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