Sustainable Visitor and Education Attraction at Gibson Mill
Multiple developments at a listed mill in Yorkshire have been used by the National Trust as a flagship example of environmental sustainability in a historic building.
Gibson Mill near Hebden Bridge in West Yorkshire dates from around 1800 and is listed at Grade II. Built in a heavily wooded valley over a mile from the nearest road, it was one of the first mills of the Industrial Revolution, driven by a water wheel and producing cotton cloth until 1890.
In the early 1900s the mill offered a variety of entertainments to locals, including dancing, dining, roller-skating and boating. After the Second World War it slipped into disuse. It was acquired by the National Trust but remained largely unused until the 1990s, when an ambitious project was suggested: to restore the site as a highly sustainable working visitor and education attraction while preserving its historic qualities.
Delivered by architects EcoArc and supported by a grant from the National Lottery Heritage Fund, the project brief required the building to be independent of all mains services, relying solely on the natural resources found on-site. The mill also had to be capable of demonstrating sustainability principles including the use of local labour and recycled materials where possible. All new facilities had to be set entirely within the existing structure’s historic fabric.
The weaving shed’s original roof had been lost many years before, and was reconstructed using oak sourced from the Trust’s woodland and dressed by a local sawyer, and covered externally with locally sourced, reclaimed stone slates.
The existing floor was very damp with severe cracks in its flagstones. Each stone was numbered and set aside for reuse, and the new floor was insulated before being prepared with a traditional lime mortar bed. The existing stones were then reset in exactly the same position as before.
Gibson Mill uses a wide range of renewable sources to meet its energy needs throughout the year. Solar panels to provide hot water and electricity were installed so as to respect the appearance of the mill and have a negligible impact on its historic structure.
Elements of the mill’s existing hydro system are used to provide electricity, including a restored 1926 turbine and a smaller turbine for use when water levels are low. Like other electricity sources, the hydro energy output from the turbines is integrated into the building’s overall energy management system.
As the system has no back-up from the national grid, the team incorporated many energy-efficient devices – for example the fridge is 10 times as efficient as a traditional model. The mill uses a wood-burning stove and boiler to provide cooking, hot water and space heating, and its café stove is a traditional Swedish model which has only one burn per day, after which heat is gradually emitted over a 12-hour period to save on fuel and minimise indoor pollution.
The system also includes a battery store to smooth inputs and peaks in demand, and provide electrical energy to appliances during periods where both hydro and solar input have dropped. The switchboard and energy management system is laid out as a visitor display and designed to be easily interpreted by the public.
The building’s waste systems are also designed to be sustainable – for instance sewage is treated on site by a non-electric device that separates solids from flushed water and composts these in a dry chamber primed with earthworms. Over time the dried-out solids become a natural, benign fertiliser which can be returned to the woodland floor.
Since the project’s completion in 2005 the mill has continued and built on its sustainable approach. The batteries were replaced in 2019, and all light bulbs originally installed are gradually being replaced with super-efficient LEDs.
However, the site has also faced difficulties such as a general decrease in water flow from the river, and the larger of its hydro turbines is currently not in operation. The degree of the project’s success has also produced its own challenges, as significantly increased visitor numbers have placed increasing strain on its facilities, and its staff work carefully to accommodate this, including planning in advance for days with high expected visitor numbers.
Gibson Mill is self-sufficient in energy, water and waste materials and its only mains connection with the outside world is the phone/broadband line. It was the first heritage building in England to be used as a visitor centre operable all year round in a solely sustainable way and has become a source of inspiration for individuals and organisations considering similar developments, winning numerous awards.
Gibson Mill and Hardcastle Crags now attract around 150,000 visitors per year, and staff estimate that since 2009 the mill has generated approximately 12,000 kilowatt hours of electricity each year thanks to their hydro scheme and photovoltaic panels.