Aluminium in the frame

As one of the most abundant metals on Earth and renowned for being endlessly recyclable, it’s easy to see why aluminium has become a popular and effective choice of building material. Aluminium windows and doors have also enjoyed a huge surge in popularity thanks to advances in both the manufacturing and fabrication processes as Mark Wheatley, technical director from leading fenestration designer and manufacturer Senior Architectural Systems explains.

It’s probably fair to say that the earliest examples of aluminium window frames were far from inspiring, with a reputation for being prone to condensation and offering limited design appeal by being predominately only available in silver. If we take a look at the aluminium products on the fenestration market today, it’s clear that the use of this impressive metal has enjoyed an evolutionary process that has been led by manufacturers looking to innovate and improve.

From silver to ‘green’

The first aluminium windows provided a much needed alternative to both domestic customers and commercial specifiers alike. Not only do they offer exceptional durability which outperforms traditional timber windows but as well as strength and robustness, they provide a sleeker, more aesthetically pleasing finish than UPVC. However, as aluminium is in itself a good conductor of heat and a poor insulator, on its own it offers little protection from heat loss and solar gain. It wasn’t until manufacturers looked to make technological advances in the thermal performance of aluminium that these metal framed windows really came into their own.

The development of thermally broken window frames provided a much needed solution but even so, the earliest examples were not without their issues. The use of polyurethane as an insulator to prevent heat loss between the inner and outer frame provided only limited thermal performance and was prone to shrink over time and create leaks in the frame. The next generation of aluminium framed windows use a much stronger polyamide to create a thermal break and provide increased protection against heat loss. However the everchanging building regulations and requirement for even lower u-values, has created a need for aluminium windows to offer even greater levels of thermal performance. One pioneering innovation is Senior’s new PURe® system, which is the first on the UK market to incorporate a thermal barrier made from expanded polyurethane foam, a material that is more commonly used in insulation and cladding products and that has long been recognised for its excellent thermal properties.

Designs for life

As all properties can lose heat through doors and windows, thermal performance is a key deciding factor when choosing a system but so is aesthetic appeal. With this in mind, modern aluminium windows have evolved to ensure that even the most demanding design briefs can be met. Offering exceptionally slim sightlines, aluminium frames have the strength to accommodate larger expanses of glass which not only dramatically improve the look of the window but also maximise the flow of natural light.

Advances in powder-coating technology also enables suppliers of aluminium windows and doors to offer an even great choice of finishes and colour options – the days of being strictly silver are long gone. Additionally, the use of dual colour, with different colours on the interior and exterior surface, has been made possible owing to the new ways that the frames are manufactured.

The design flexibility of aluminium windows and the narrow sightlines that can be achieved have made them a popular choice for use on a variety of applications from modern, new build projects to renovation contracts. Its unrivalled durability and low-maintenance properties also make aluminium the ideal material for windows and doors in high-traffic environments and as such has become the preferred choice for a range of sectors including education and healthcare.

Making progress

Despite the major advances in the thermal performance of aluminium windows, manufacturers such as Senior have been keen to ensure that innovation doesn’t have to carry a hefty price tag. A key strategy in the development of Senior’s aluminium products and particularly in the creation of the PURe® range, has been to ensure that the products not only work well when installed but that fabricators and installers find them easy to work with. For example, despite its innovative construction, value engineering of the new PURe® system has ensured that trade customers can fabricate the new windows without any changes to existing manufacturing equipment.

The use of aluminium as a building material is vast and its cradle –to – cradle recyclability makes it exceptional. As the performance and qualities of aluminium windows and doors continues to evolve, the potential for this market certainly makes it one to watch


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