Build June (2016)

Build Magazine 63 Real Estate As the demand for affordable homes increases, London’s skyline has become an ever-changing landscape. The need to maxim- ise available space has led to developers and housing associations alike opting for high-rise residential developments, while the NLA re- ported in March this year that in London 233 high-rise buildings have planning permission and a further 114 towers are at planning or pre-application stage – 73% of which specify a primary residential use. Yet the drive to build up is not a modern phenomenon. Many will remember a similar home-building drive in the post-war era of the 50s and 60s, in which tower-blocks rose up across the country. The development of new building technology in the form of pre-cast concrete frames meant that high-rises were seen as a quick and affordable way to provide much needed public housing. It is this period of construction that led to the term ‘concrete jungle’, as complex and interconnected towers with a myriad of enclosed corridors grew up to house a booming population. However, as the phenomena reached its peak, awareness began to grow of the multitude of social issues emerging within these commu- nities in the sky; including social alienation, mental health difficulties, and rising crime levels. The infamous collapse of Ronan Point in 1968 marked the U-turn in public attitude towards the tower-block and a significant shift in design and building regulations (including the requirement to design against dispropor- tionate collapse). The 1972 oil crisis led to a further change in building regulation and the thermal regulation of tower-blocks. Concrete cladding now also had to insulate and the concept of the facade was born, which essentially wrapped the buildings in cotton wool and regulated heat loss. This meant the towers of the 60s quickly became outdated and ill favoured, plagued as they were by cold, damp, and draughts. Many early high-rise towers have since been demolished with the phrase ‘tower-block’ almost a dirty word in the residential sector. So as a multitude of multi-storey buildings shoot up across the UK, what moves have been made to ensure history will not repeat itself and that we will not be building slums of the future? Fundamentally, towers need to be in the right location, look good and be built well. Amenities and local infrastruc- ture, including particularly good public transport links, are a key component to delivering happy residents and achieving high densities. Not all early towers were universally disliked and both the Barbi- can and Trellick Tower continue to be regarded as design icons. Good design, like good art, sparks debate and a tower should contribute to the sky-line. These days, concerns around structural safety do not even enter the public consciousness, thanks to ever increas- ing advancements in the quality of materials, improved design codes and lessons learnt from across the globe. New technologies are also pushing the boundaries in sustainable design and reducing embodied carbon from the use of post-tensioned or precast concrete to the ever increasing use of cross-laminat- ed timber in medium-rise schemes. Future proofing is now in-built within most projects with provisions incorporat- ed for changes in trends and use. Homes are being made adaptable in terms of space and configuration, as well as the integration of various automation require- ments and digital technologies that may control our homes in years to come. Vertical transportation is critical for high- rise and in historically was a key concern where lifts were often out of service resulting in the climbing of many flights of stairs. Lifts are now faster, far more reliable and are often fitted out to act as a seamless extension of the well-designed lobbies that they connect. Façade treatment now has to be well considered, not only from a thermal and waterproofing view but also a mainte- nance perspective. In the past cladding on many towers has not been maintained which has led to many of the highlighted issues. Today we design in façade access for maintenance and/or make use of durable materials that require minimal maintenance. As high-rise residential developments reach new heights, what have we learned from the failed tower-block? As a new generation of towers go up, this time labelled luxury apartments rather than tower-blocks, Ramboll Residential Team Director Tom Shaw asks how the industry is working to prevent history repeating itself.