PROJECT FOCUS GREEN RETROFITTING


THETOWN HALL OFTHE FUTURE


Scorching heat, torrential rain, high winds … who knows how a building from the 20th century will react to what the next 100 years will throw at it? Well actually, thanks to a pioneering project by WSP, funded by the Technology Strategy Board, we are starting to find out.


Matthew Payne, technical director in WSP’s Built Ecology team, spent three months on a detailed analysis of Trowbridge County Hall in Wiltshire, working out the greatest risks to its structure and developing a dynamic strategy for the next century. “There’s no blueprint for this kind of study, so we’re really bashing a new path,” he says. “We’ll be having drier summers, wetter winters, more intense rainfall events. Our job is to bring some clarity, combining forecast


TROWBRIDGE COUNTY HALL


UK climate data with the specific characteristics of the building and translating it into something the client can understand.”


WSP is also the main M&E consultant on Wiltshire council’s property rationalisation, under which Trowbridge will become one of just four sites. Constructed in the 1930s with a major extension in the 1970s, it has led to some interesting comparative conclusions. “The 1970s building has quite deep floorplates, providing less opportunity for increasing natural ventilation and daylighting than in the older one, built before our


over-reliance on air conditioning.”


The obvious solutions have not always turned out to be the right ones. “There are cavity walls in both buildings, which we could fill with insulation. But we identified the risk of damage to the facade by wind-driven rain. Water could seep into the insulation, acting as a conduit between the outside and the inside.” Instead, insulation will be installed inside the building – losing any potential cooling effect from the exposed thermal mass. “There are other ways to deal with thermal comfort but water ingress can be very destructive and expensive to fix.”


WSP’s analysis of surface water, groundwater and fluvial flood risk led it to recommend offices and equipment in the basement be relocated. Longer term, it has established monitoring of the wall ties and soil and ground conditions, to provide a 10-15 year warning of danger to the foundations. Meanwhile, there will be some changes to the grounds around Trowbridge County Hall too. “We looked at putting shading on the building, but it would have been hard to integrate it with the 1930s shading. So we recommended providing more natural shading instead. That’s a nice way of doing it, because as time goes on and the climate gets hotter, the trees will get bigger.”


matthew.payne@built-ecology. com


A NEW CHAPTER


The public library of Cacica in Suceava County, Romania, doesn’t, at first glance, seem like a very ambitious building. And yet this modest wood and brick structure is at the centre of some very big plans.


The ecoBiblioteca project, developed by the Romania Green Building Council, aims to transform a typical library in a small community into a state-of- the-art facility and an exemplary sustainable building, an inspiration for more than 1,500 libraries across the country and for the Romanian construction industry.


WSP is the engineering consultant on the project, and


has been working with the 5,000-strong local community to identify the problems and the most effective solution. “It’s much harder to improve an existing building than build a sustainable building from scratch,” says Cristina Gruschevici, an MEP engineer with WSP in Bucharest. “Before, the library was not at all sustainable, and it needed a lot of refurbishment.”


The existing building was poorly insulated with no hot or cold running water, heated by three wood-burning stoves in each room and supplied with water by an adjacent well. Away from the windows, the rooms were very dark even on the sunniest


days. The roof was found to be structurally unsound, and there was asbestos in the roof tiles. But when the refurbishment is complete this summer, it will provide bright, comfortable, flexible spaces that welcome both local people and tourists. Gruschevici estimates that this much higher quality facility will use 35-40% less energy than comparable buildings.


The exterior of the building has been upgraded with 200mm of sheep’s wool insulation and a new ventilated wooden facade in harmony with the local architectural style. The building will still be heated by wood, as it is an abundant local source of fuel, but via a wood-burning biomass boiler, which will feed an underfloor heating system. Hot water will be provided by roof-mounted solar panels, and all lighting will be via natural daylight from sunpipes and LEDs.


Low-energy laptops will be used throughout the facility and the reduced cooling load will be met by a natural ventilation system and night purging utilising the thermal mass of the original masonry structure. Rainwater will be collected on-site and used for irrigation and toilet flushing.


For the WSP team, it’s exciting to work on such a pioneering project, though there have been difficulties. “We are trying to use sustainable, green systems that had never been used before in Romania, so that was one of the biggest challenges,” says Gruschevici. But one of the best things about the project has been the enthusiasm of the local community. “The local authority is hoping that it will attract a lot more tourists to the area – it’s unique in Romania, so we hope people will want to visit.”


cristina.gruschevici@wspgroup.ro SOLUTIONS 11

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