Windows are one of the most important elements of any property, so effectively sealing them for optimum long term energy efficiency must be a top priority, says Andy Swift of ISO-Chemie
The success of a renovation or self-build project can be defined by the choice of windows and doors. Get it right and the property can look superb; adding real value for years to come. However, pursue the wrong route and the disappointment can linger for years. The same can be said of how the units are sealed. Indeed, while there have been advances in glass and frame technology in recent years, way too many projects are being let down by poor or ill-equipped window and door installations.
BUILDING REGULATIONS
Changes to Part L of the Building Regulations, which came into effect earlier this year, place the emphasis on stricter standards and compliance procedures around energy and ventilation performance, contributing towards a roadmap to a net zero carbon future and properties designed and built in-line with stricter carbon emissions targets. Specifically, to ensure continuity of the air barrier, window and door units will have to connect to the primary air barrier and the frames will need to be taped to surrounding structural openings using air sealing tape.
This comes against a landscape where evidence points to doors and windows as the main source of continuing energy inefficient properties. Indeed, in the light of product innovation over the years, it’s almost criminal that the hundreds of thousands of self-build or retrofit installations completed each year go unchecked or unregulated. This is a pity because with advancements in cost effective, easy-to-use technologies, there isn’t a justifiable reason for delaying or avoiding the specification and installation of better sealing solutions.
The new Part L is to be welcomed, and sees requirements for improvements in air tightness, forcing it from 10 air changes per hour down to 8 air changes per hour and also U-value on windows shifting from 1.6 to 1.2 W/m2K. This places an onus on using more energy efficient sealant solutions and the requirement that the window frame should be linked back to the wall with an air-tight tape.
Heat will always find the fastest exit as it meets the ‘A’ or ‘A+’ rated window, and invariably this emanates from the 10 mm or so expansion gap left around the window following fitting. This is normally left empty, but an amount of spray foam can be injected to fill the void before a silicone trim is applied for a smart looking finish. Unfortunately, as expedient as this might seem, none of these solutions create a measurable, long term, high performance thermal, acoustic or airtight barrier – the U-value of the installed window is simply reduced, which leads to heat escape and, ultimately, financial losses.
That’s why the property and building sectors deserve better insulating solutions to improve energy efficiencies, especially if as predicted, the UK market stays buoyant over the next 12 months as the economy continues to recover from the pandemic and building and construction activity remains busy, particular in the face of a chronic national housing shortage and the need to build more affordable housing.
Modular construction, which is gaining increasing traction, is seeing continued integration with the more traditional methods of building, enabling self-builders to bring forward projects more expediently. Designers and specifiers are looking at ever more expeditious ways to deliver low carbon structures that use sustainable technologies to deliver measurable airtight, acoustic and thermal sealing benefits.
Building Regulation changes will have an unequivocal impact as energy ratings for property become stricter, and these include energy and ventilation standards for new homes that are far better for the environment and fit for the future. It’s hard to argue that higher air and thermal standards for house construction has to be a continuing priority.
Innovative sealing technologies are undoubtedly a beneficial way to help self-builders and renovators have the energy efficient homes we all want. Indeed, as sustainability continues to be of paramount concern in the development of low carbon and eco-friendly building projects, we will see technologies such as ‘energy foam tapes,’ which can add real value during the initial and post construction phases, grow in importance as effective ways to seal window and door frame expansion joints and gaps.
PRIORITY SEALING
The need for more effective insulation and sealing solutions of windows and doors will become a priority for the self-build and renovation sectors. Indeed, it could be argued that retrofitting sealing solutions can be an effective way to achieve greater energy efficient homes rather than building new properties. In the self-build market, designers will continue to invest in new ways to deliver low carbon structures, which use sustainable technologies such as foam sealant tapes to secure measurable airtight, acoustic and thermal sealing benefits.
With 25% of the heat leaking from around windows it will become ever more critical to improve the seal around the window to wall gap if the amount of heat loss around frames is to be significantly reduced, helping to save energy costs in the process. Retrofitting properties with effective sealing solutions must also become a direct focus for self-builders and those involved in refurbishment and home renovation projects. As they say the greenest home is one already built – it just needs proper retrofit insulation.
Andy Swift is sales and operations manager for ISO-Chemie