The increasing preference for aluminium in window and door frame construction owes much to its versatility and growing competitiveness. As a result, increasingly diverse projects are being seen across the client spectrum, from prominent commercial clients in the public and private sectors to ‘high end’ self-builds.

Despite the competitive nature of the doors and windows sector, a few manufacturers are achieving clear differentiation through their technical and service capabilities. This is proving essential to meet the growing demand for greater flexibility of product performance and assistance throughout the design process.

Ever tighter building schedules are also putting added pressure on lead times. This has made the ‘just in time’ approach to manufacturing impractical so maintaining stock of the extensive range of standard profiles, typically 1.1 to 6.1 metres, can make a critical difference. It enables fabricators to keep wastage levels to a minimum and provides lasting assurance that they can submit tenders at a consistently competitive level. The knock-on effect has been a clear trend in the proportion of their work accounted for by aluminium rather than PVCu.

For orders in which bespoke features such as RAL colours are involved, production capabilities have also had to be changed to enable quick turnaround. Where once the norm for site delivery was measured in weeks it now has to be days. It requires use of sophisticated, automated production facilities and consequent confidence to invest in them. The need for sustainable manufacturing has also resulted in the highest levels of powder recovery ever.

In terms of the visual aesthetic, window and door design has not only kept pace with requirements of contemporary architecture but is positively influencing it. Use of sleek profiles which maximise the glazing area while remaining secure, inherently strong and energy-efficient has become commonplace. However, with increasingly high standards of manufacturing come concerns that some will compromise aluminium thickness to maintain their market share. For effective long-term performance a specifier should, therefore, make clear the minimum requirement in accordance with Standards such as  BS 6375 Part 2 - Specification for operation and strength and BS 4873 - Specification for aluminium alloy windows and doorsets.

To put the value of a manufacturer’s technical potential contribution into perspective, fenestration accounts for up to 40 credits of the 119 available in a BREEAM assessment. As a result of demand for lower U-values and collaboration with specifiers Kestrel Aluminium Systems were prompted to design a 70mm casement window. It will provide the highest standard of acoustic performance and weather tightness and is scheduled to be available early in 2020 .

Individual projects which have benefitted from such collaboration include the newly refurbished and renamed ‘Ellen Terry Building’ for Coventry University. The Grade II-listed, art deco former Gaumont Palace Theatre’s design required an elegant run of modern, thermally broken commercial doors which matched the original façade. In addition to meeting the minimum requirement sof PAS 24, incorporation of card scanners and perfect replication of the doors’ original slim sight lines were required. This has been achieved through use of carefully designed lay bars, which led the University FM team to comment “The new doors have recaptured the original design purpose while the increase in natural light has resulted in consistently positive feedback”.

A limited refurbishment schedule also placed pressure on HTL Windows and Doors to undertake a frontage upgrade to the entrance to ZSL Whipsnade, the UK’s largest zoo. A five week period prior to Easter gave little time for manufacturing, fabrication and installation of automated doors (which considerably exceed Building Regulation requirements), a 60mm window system and 125mm curtain walling. Consequent enhancement of natural light allows visitors immediate views into the main zoo areas but just as importantly for the client the end result makes a clear statement about ZSL’s standards for Whipsnade facilities management in the 21st century.


A Cross, Kestrel Aluminium Systems

180 Rupert Street
B7 5DT

T: 0121 333 3575


N Pittman

T: 07976 269880