The tall building phenomenon

Dan Thomson, CABE design review advisor, debates the positive effects and pitfalls of tall buildings.

An unprecedented wave of tall building proposals has come forward in recent years. This has caused fevered debate about both individual schemes and the role of tall buildings. Their very size and prominence means that, for good or ill, they have a significant impact on a place and its character. But there does seem to be growing acceptance that as long as tall buildings are well designed and suitably located, they can be a positive way to develop in urban areas.

The context

There has been widespread public distrust of tall buildings. The post-WWII wave of designs may have included some excellent buildings - Centre Point and the Barbican Towers are now listed - but it was the mistakes of this era that really stood out. Tall buildings became synonymous for many people with cheaply built, badly maintained blocks of flats or offices which failed to meet the needs of their users and did little for their local environment.

The Gherkin - or 30 St Mary Axe as it is properly called - has perhaps the best claim to being the breakthrough development which changed public attitudes. Opened in 2004, it has redefined what a tall building can look like and has shown that a tower of first rate design quality can be extremely popular with the public as well as working well for its users. Along with other high quality designs that have been approved after public inquiries - the Heron Tower and London Bridge Tower - the success of 30 St Mary Axe has helped create a far more favourable climate for tall buildings proposals.

The potential advantages of tall buildings

Many people now agree that high density accommodation, whether for office, residential or mixed use, is advantageous. Building tall is certainly not the only way to achieve high density but it can make sense in situations such as confined areas of a city where land is scarce. Tall buildings are also particularly suited to locations close to public transport nodes, reducing the need for car use.

Arguments have been put forward for tall buildings as catalysts for regeneration. One Canada Square, the central building at Canary Wharf and still the tallest in the UK, was an early example. Despite having to contend with a recession shortly after construction, it sparked the transformation of the Isle of Dogs. Fifteen years later, new towers cluster around it and the area has become a major financial, and increasingly residential, area. While the office space contained in One Canada Square could have been provided in a lower building occupying a greater floor area, as a tall building it worked as a beacon, boldly signalling that the area was enjoying major investment.

The positive effect that a tall building can have on perceptions can extend to entire cities. The recently completed Beetham Tower, for instance, attracted huge media interest and has promoted Manchester's image as a modern and dynamic place.

In terms of heritage, tall building proposals are often controversial because of the inevitable impact on the historic urban fabric, both at street level and on views. But if the design is well thought out, this can be a beneficial impact. In places like the City of London, for instance, the fine medieval grain of the streets could be better maintained by the relatively small footprint of tall buildings than the much bigger footprint of 'groundscrapers'.

Like all new developments, tall buildings must address sustainability issues. Their form can gives them potential advantages, such as ample access to sunlight and wind power for the incorporation of solar panels and wind turbines.

Potential problems with tall buildings

Some of the major potential drawbacks of a tall building are mirror images of their potential benefits, and it is usually the quality of the design that governs which way it goes. A badly designed tall building that is unattractive and doesn't work for its users can harm the image of a city. And towers are environmentally damaging if they fail to incorporate energy efficient design solutions to deal with heating, cooling and ventilation.

One of the principal problems with tall buildings of the past, even those that offer great architecture, has been a failure to think through how the structure meets the ground. Disappointingly, this remains a common problem. Many developments block pedestrian movement and offer little in the way of public space and facilities. An excellent tall building should positively enhance its locality and share the benefits of the investment it represents by providing public access around, through and in the building. CABE particularly advocates access for the public to the top of tall buildings, so that views can be widely enjoyed.

Looking ahead, the main pitfall may come from the growing number of proposals for tall buildings in smaller cities and the suburbs of London. Building a tower is an immense financial and logistical undertaking. Some of these places simply do not generate the sale or rental value to support the quality of design, materials and detailing needed for such prominent buildings. In this situation, the risk is that low quality towers will be built instead, or slabs that maximise floor area at the cost of good design.

Considering proposals

This makes rigorous assessment of tall building proposals vital. CABE and English Heritage provide advice on such proposals and in 2003 issued joint guidance on tall buildings which outlined how the two bodies evaluate them. The basic premise of the guidance is that tall buildings are not inherently a bad thing, but because of their prominence they must be of the highest design standard. Ultimately it is up to local authorities to decide whether or not to grant planning permission for a scheme, and the joint guidance helps their assessment.

It also gives them a starting point to prepare local policies about tall buildings. Having a policy framework which is attuned to local circumstances and gives developers certainty about the standard of design and construction expected is crucial to ensuring good quality. Every local authority likely to receive proposals for tall buildings should have a policy in place. Not all yet do, but the planning system is moving towards a more plan led and pro-active system, and the pressure will be growing on those local authorities without policies to put them in place.

The future

Demographic and economic pressures in London and the core cities are likely to result in more proposals for tall buildings. But of course not every scheme that gains permission will be built. If local authorities put in place robust policies, and take advantage of the design advice available to them, the tall buildings that do get built should be well designed assets for their city.