A journey from draughty single glazing to vital thermal barriers

// the building envelope

The needs of our clients and members have always influenced our framework direction, but one thing remains consistent, write John Skivington, LHC Director, is the need to produce thermally efficient homes and components for public sector use.

Some frameworks come and go. But quality focused frameworks evolve over time and become industry benchmarks such as our PVC-U framework which, has delivered nearly  £250m of works since 1980.


Over the past 13 years, it's been produced by LHC Technical Consultant, Chris Powell, who also serves on the national BSI technical committee for windows and doors and is Chairman of the drafting panel responsible for revising BS 8213-4 for the survey and installation of windows and doorsets.


So why is it so popular? Well, let’s start at the beginning...


In 1966, LHC is formed at a time when much of the country’s council housing has fallen into disrepair and is beginning to be replaced with high density housing and tower block living. 


Windows and doors are predominantly timber, but aluminium is beginning to become popular, after marketers claim it is “virtually maintenance free”. Single glazed units are the norm with energy efficiency barely being given a second thought. These “modern” units were considered a huge improvement, keeping out the cold.


“Keeping out the cold” as opposed to “keeping in the heat” was the thinking until the early ‘70s. However, the 1973 oil crisis led to the realisation that a more energy efficient approach was required.


1970s window designs became more energy efficient, with sealed glazing units. Rubberised draft stripping is introduced on timber sashes and brush pile on aluminium. However, weatherproofing efficiency isn’t great. Old timber or steel windows are replaced with aluminium units which developed from anodised finishing to the more attractive white powder coated frames.


Coupled with the conservative government’s moratorium on new council house building, more and more refurbishment projects were being rolled out into the 1980s. Efficient fabrication techniques, window design and replacement expertise meant that large swathes of council housing could now be “re-windowed”, quickly and comparatively inexpensively.


During the 1980s, PVC-U systems were being introduced that were larger in profile size than the aluminium and timber frames they were to replace. During this time, we recognised their potential benefits and developed our first PVC-U framework.


As profile designs became slimmer and more appealing to architects and planners, the use of PVC-U windows and doors exceeded other materials and PVC-U products become the UK’s most widely used window and door material through the 1990s.


In 2002, new Building Regulations for thermal efficiency and compliance with a means of escape in the case of a fire came into play. The Kyoto Protocol, to reduce greenhouse gas emission, was adopted in 2005.


Now minds were concentrated on the thermal efficiency the external envelope of buildings – not least the windows. Today, all three materials nestle comfortably together.  In response, considerable research and scientific progress has been made in the development and design of glass and glazing units, thermally efficient profiles, hardware operation and weatherproofing .
Fast forward to today... our objective is to ensure our clients receive the best solution on the market, whether it’s for Aluminium, Timber or PVC-U products.


Our ninth version of our ever popular PVC-U framework is going from strength to strength. offering a range of styles using high performance profiles, colours and patterns to meet the needs of all public sector users. Enhanced security options, in line with PAS 24 and Secured by Design, are also available.  All the products are CE Marked and conform to the appropriate British Standards. 
For nearly 50 years, we have continued to deliver free-to-use industry leading frameworks for all public sector bodies. Our aim of delivering trusted procurement for better buildings and homes is forever engraved in our culture, and remains at the forefront of our business.

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