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Brownfield Site Feature - Is brown the new green?
Brownfield sites are being redeveloped at a rapid rate as demand for housing and commercial space continues to increase. Clive Williamson, Managing Director of Ocon Construction, discusses the history of brownfield sites, the challenges that they represent and the sustainable and eco-conscious opportunities they provide in order to regenerate dilapidated urban areas.
In 2005 there was a total of 63,500 hectares of brownfield land left undeveloped in England. This land has been targeted by the government as prime location for residential space and with the population rapidly rising, this land will be essential to help meet plans to build 3.8 million new homes by 2021.
England has a significant, although decreasing, amount of industrial wasteland that has been left abandoned and acts as an unsightly reminder of some of the country's heavy-industry past. Much of this land began to be neglected in the 1970s when Britain's staple industries, which had been the backbone of the nations economic success for so long, began to experience rapid decline. Shipbuilding, mining, manufacturing and the construction sectors all suffered as Britain struggled to adapt to a more service-based and consumer orientated economic climate. These brownfield sites left behind a stark visualisation of the economic decline that regions such as the North East and North West, amongst others, were experiencing at the time.
Land that had previously employed hundreds of people and acted as the focal point for some communities began to slowly fall into a state of disrepute and blot the urban landscape. However, in the 1990s, in a bid to meet rising housing targets and regenerate urban areas that had begun to attract crime, vandalism and anti-social behaviour, the British government encouraged redevelopment of this type of land.
For instance, in February 1998 the Labour Government launched the 'Planning Policy Guidance Note 3' document, which set a national target for England to build 60 per cent of new homes on previously developed land by 2008. The 60 per cent target has already been overwhelmingly met - eight years ahead of schedule - and the reclamation and reuse of brownfield land has been a major factor in the regeneration and modernisation of UK towns and cities. This target co-incided with the policy document 'Planning for the Communities for the Future', which was the catalyst for a concerted government initiative to bring previously developed land back into productive use.
For instance, the former industrial glory, and subsequent de-industrialised wasteland, of dockland areas in Liverpool and Newcastle have now been transformed into cultural hubs that boast an array of restaurants, bars, museums and apartments that manage to retain the positive traditions and heritage of the cities.
Redevelopment provides an opportunity to recycle existing land, clean contaminated land, encourage economic regeneration, promote environmental awareness and provide a habitat for the growth of flora and fauna. One of the most persuasive arguments, however, is that by re-developing brownfield land, green belt land remains protected. Just as there is a need to recycle paper, glass and plastic there is also a need to recycle land. With the demographics of Britain being a small island with a large population this is even more pressing.
However, there are significant challenges surrounding the regeneration of brownfield land, such as effectively resolving the issue of soil contamination. Many brownfield sites are situated in urban areas, where in the past, some form of heavy industry has taken place which has resulted in the surrounding land becoming polluted with toxic chemicals and other forms of hazardous waste. In previous years the preferred solution in dealing with this was to excavate the contaminated land and send it to landfill on the back of lorries and replace the removed soil with fresh material. However, the introduction of a landfill tax in 2005, which now implements a £80 charge for each tonne of material dumped into a landfill site, has reversed this trend and encouraged remediation techniques.
An example of this approach in action was apparent at Ocon Constructionﾒs Chettle's Yard project in Nottingham, 2007. This site will eventually be transformed into a large student accommodation complex, consisting of 1,000 bedrooms, a showroom and retail facilities. Before re-development began, the site had become an abandoned industrial wasteland with the soil badly effected by leaking fuel tanks and the deliberate disposal of oil, petrol and diesel. Therefore, the site required a significant amount of land remediation in order to make it fit for development ' and the preferred technique of cleaning up the site was bioremediation.
The process of bioremediation is one in which naturally occurring microbes are used to remove toxic chemicals from the soil. The microbes feed on the pollutants and as they eat away at them the contamination levels within the soil begin to decrease. To speed up this process warm water is filtered onto the site through pipes as this helps to ensure the natural microbes (fungi and bacteria) work at the correct temperature and to the optimum rate.
The major benefit of this process is that it eradicates the need for hordes of lorries to constantly travel back and forth from construction sites to landfill. This not only reduces motorway congestion, but also decreases pollution and disruption to local areas that are effected by nearby construction sites.
All brownfield sites have a varied and often colourful history and it is important for developers and contractors to work sensibly with this in mind. One such example is Ocon Construction's site at Hoyle Street in Sheffield, which will eventually be regenerated into a £42 million state-of-the-art student accommodation apartment with underground public car parking facilities. The origins of the site date back to the early 1800s, with industrial development on the site beginning in the late Georgian, early Victorian period with the construction of the Hoyle Street Works. This factory gradually evolved into a substantial steelworks, which had its own cementation and crucible furnaces.
The rich history of this brownfield site in Sheffield was unearthed when Ocon Construction discovered a group of industrial-age crucible furnaces. The furnaces, which were discovered in a basement that had previously lay buried beneath the surface, will be retained and kept as part of the new building. Under specially supervised conditions the public will be allowed to visit the basement to have a glimpse at the industrial past of the area. Ocon Construction, as a leading ethical contractor, realise the importance of respecting the heritage of a site. The company will stringently adhere to Note 15 ﾖ 'The Historic Environment' in the 'Planning Policy Guidance' document to ensure that the history of this site is maintained and incorporated into the new building.
The arch feature within the basement will be retained and the repair of the walls will respect the existing fabric and match it in materials, texture, quality and colour. Ocon Construction will also clean and paint the iron tie straps and maintain the furnace holes as a feature. The original design of the room will be preserved, with no partitions being introduced to break up the space and the false ceilings within the basement will be removed and the original ceilings restored. All of this is an example of how construction companies should respect the heritage of sites. By maintaining the furnace basement this will act as a reminder of the 'Steel City's' proud industrial past.
It is clear that brownfield sites can raise a plethora of challenges for contractors that require a flexible and well-judged response in order to deal effectively with any problems that arise. One such instance that required a sharp response was at Ocon Construction's Manor Mils site in Leeds. Following stringent inspections by engineering contractors it was discovered that a 100 year-old building, only six metres adjacent to the site, began showing signs of movement when work began on the Manor Mills site. The immediate response was to stop all works to ensure health and safety.
After the situation was thoroughly assessed, it was decided that the best way to progress would be to build a pile wall to support the foundations of the destabilised building. To achieve this 56 Continuous Flight Auger (CFA) piles were installed, which is a method of drilling piles into the ground and replacing soil with concrete in order to add strength to the building. The concrete is injected through a hollow shaft under pressure as the auger or drill is extracted - this creates a continuos pile without ever leaving an open hole. The procedure took three weeks to complete, but ensured the long-term survival of a building with historical and cultural importance.
All of these sites highlight the variety of challenges that a brownfield site can raise, but ultimately the benefits of redeveloping this type of land far outweigh the challenges. With the spectre of climate change debate broadening day by day, defending greenbelt land, and thus protecting the atmosphere from increased carbon emissions, is the major argument for the re-development of former industrial wasteland. A fine balance exists between protecting the countryside and meeting housing targets and by selecting brownfield sites for redevelopment, this creates a sustainable mode for growth.
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