Draught proofing a 300 year old mill

Nestled on the edge of the beautiful Peak District, alongside the banks of the River Dane is the tiny hamlet of Gradbach. At its heart is Gradbach Mill, a stunning building set amongst 16 acres of land, steeped in history and heritage dating back to the silk spinning days of the late 1700’s.

At various times in its history the Mill has played its part as a youth hostel, cow shed, farmhouse and doctors surgery, in addition to its original purpose as a flax and silk mill.

In 2013, it was acquired by Newcastle under Lyme College who had been taking groups of its engineering students to the youth hostel for a number of years to participate in ‘outward bound’ type activities in the area. The College set to work upgrading the property to transform it into a centre for experiential and outdoor learning, which will be operated through a subsidiary company, Gradbach Limited.

Thanks to the vision of College Vice Principal Craig Hodgson, assisted by Head of Estates Martin Bostock and Architects Ellis Williams, the buildings have been beautifully refurbished, and the main accommodation, which during its hostel days had catered for 80 guests, will now sleep a much more comfortable 30.

“We wanted a facility that was appropriate for this amazing setting,” said Martin. “Something that would provide a great educational resource for Newcastle under Lyme College, as well as for other schools and colleges, whilst at the same time appealing to corporate and private guests.”

To raise the quality of the accommodation to such high standards was understandably difficult, particularly given the challenges presented by the isolated location. Where possible, the College has chosen to use local craftsmen to support the local economy and their skills are evident in the quality of the masonry, joinery and dry stone wall restoration.

Being faithful to the Mill’s underlying aesthetics was extremely important, but as you might expect for an exposed building almost 300 years old, this presented a greater challenge when it came to the existing windows, as Martin explains: “The original windows were in a poor condition and were extremely draughty. The building, particularly the bedrooms, were perishing in winter. Those Youth Hostellers were a hardy bunch, but even they could not have failed to notice the scale of the problem. A new heating system was essential, but the glazing quality would mean much of the energy would have been lost if we hadn’t tackled the windows.”

Granada Secondary Glazing set to work providing horizontal sliders from its Heritage range to completely transform the noise and thermal insulation. Not that the surrounding noise was an issue – the picturesque surroundings provides complete silence – but a large air gap was still utilised to provide maintenance and cleaning access to the primary windows, via a centre pivot opening.

It was the draught prevention that first impressed the team. “It has to be seen to be believed,” says Martin. “The original windows were no longer up to the job, but even so, with the secondary glazing installed, you would be forgiven for thinking the outside elements are much gentler than they often are!”

In addition to the high-tech fixtures, 6.4mm Low-E glass was also used, to add to the thermal performance. In independent tests, the addition of secondary glazing with Low-E glass has proved to transform windows with C ratings or lower to A Rated — a 63% boost in heat insulation.

Smooth sight lines, ease of operation and maintenance and an extremely smooth installation process also made a positive impression on Martin. “We are absolutely delighted with the results,” he concludes. “To bring this project to completion has been a real delight and the results are there for all to see, enjoy and experience for years to come.”