The grater good

Taking a tired old library and reinventing it as a giant funky low-energy cheese grater is not a task for the faint-hearted. Quite apart from the technical questions, you have to deal with cautious investors and conservative planners.

Architect Stubbs Rich has risen to that challenge with its design for a learning resource centre at Herefordshire College of Technology. But then it had to do something eyecatching: the entire campus was being redeveloped but the centre was to be the star of the show.

The “cheese grater” is actually a unique solar shading made from aluminium mesh. Paul Younger, an associate at Stubbs Rich, says: “It’s a very important branding element for the college as it’s right next to the road running past the site. You can also project images onto it and it acts as a backdrop for metalwork sculptures which can be fixed in front of it.”

But the planners were not keen, according to Younger. “They hadn’t seen this solution before and were worried it would look like a chicken wire fence,” he says. “They were reassured when we showed them a full size mock-up of the mesh.”

A second, somewhat less glamorous, idea was to reuse the concrete frame of the old library. Younger was keen to do this, as it made a considerable difference to the embodied energy content of the finished building. Also, its thermal mass meant the building could be naturally ventilated. Younger says the frame has a generous floor-to-ceiling height, which will help with the natural ventilation, and a spacious structural grid, which offers flexibility.

The funders were less enthusiastic than Younger about reusing the frame. They worried that that would make it a refurbishment project rather than new build, despite the fact that everything else was being stripped out.

“We had debates with the funders, as they thought refurbishment means a lick of paint and some new carpets,” says Younger. The debate took a more positive turn once money entered the equation: reusing the frame cut the cost of the new building by £750,000, or 15%, of the £5m project value.

The cheese grater is an important branding element.
You can project images onto it and it acts as a backdrop
for metalwork sculptures which can be fixed in front

Paul Younger, Associate, Stubbs Rich

The old library was itself naturally ventilated, but was overheated in summer and cold in winter. This was because its 22m depth made it difficult to ventilate the central area. The solution for the new building is to insert five “chimneys” in the centre of the structure to pull warm air up. These will be glazed to scoop natural light into the building.

The mesh on the south facade, which allows views out over the campus, will block the high summer sun, but let in low, cool afternoon sun. It will be made from a flat aluminium sheet that has holes cut in it before being pulled into shape and dumped into an acid bath to dissolve sharp edges, anodise and colour it.

The mesh is rigid and will be fixed in large panels onto a frame in front of the building, with a standard cladding system, made by Technal, behind it. Younger says discussions about colour are continuing with the planners, but he is confident the most tricky negotiations are behind them.

Kalwall will be used to clad the rear of the building. This is a sandwich of two grp sheets with a structural metal core, which will provide diffuse light to areas in the building where computers will be used. There will be a projection screen at the front of the building, on one side of the mesh.

Internally, the mesh theme will continue over what has been named the “orientation wall”. The mesh is positioned in front of a coloured wall, running the length of the building past the ventilation chimneys. It has different colours for each floor and is clad in acoustic panels to help reduce noise. There are also radiators in this area.

The idea is that the mesh will protect the delicate acoustic panels from wear and tear and stop students burning themselves on radiators.

So far, the interior has been stripped out and the old cladding will be removed by the end of the year. Then work can begin on the new elements, with completion scheduled for late 2007. Once it is finished, the people of Hereford will be able to use the building too.