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2 June, 2009
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The Britten Studio with its roof containing 314 acoustic boxes

The Britten Studio with its roof containing 314 acoustic boxes

Raising the rafters
Published:  01 February, 2009

A multi-million pound redevelopment project at Snape Maltings has timber at its heart. Sally Spencer reports

For Harry Potter aficionados, the name Snape conjures up an image of a rather sinister wizard. Others are more likely to think of Benjamin Britten, the composer who put Snape Maltings on the map.
Built in the mid-19th century, Snape was one of the largest barley maltings in East Anglia. It closed in 1965 but, a couple of years later, four of the old kilns were transformed into a concert hall, home to the Aldeburgh Festival, an artistic collaboration between local lad Britten, tenor Peter Pears and librettist Eric Crozier. The hall, now run by Aldeburgh Music, is said to have one of the best acoustics in the world.
The building also provided rehearsal rooms, but five years ago it became clear that it had reached capacity and Aldeburgh Music needed to expand into the neighbouring kilns and outhouses. These, however, were in a pitiful state – and Grade II listed.
The resulting development plan, devised by Aldeburgh Music, English Heritage, Suffolk Coastal District Council and architects Haworth Tompkins, is one of the largest non-metropolitan arts projects in this country. It called for the conversion of the derelict buildings and construction of sympathetically designed new ones for rehearsal and performance spaces.
“Aldeburgh Music wanted to keep the quality of the ‘found space’, as if they’d moved in over the weekend and set up a ruined building for a concert,” said Paddy Dillon, associate architect at Haworth Tompkins, adding that the use and reuse of timber was high on the programme.

Orchestral work
The centrepiece is the Britten Studio, a new 24x15m space intended for full orchestral rehearsals and as a 340-seat venue. Three other buildings running along its length incorporate further rehearsal studios, foyer, social areas and ancillary spaces over two floors. One of these is a renovated double-height kiln, now the Jerwood Kiln Studio, a 10x9m performance space with room for an 80-strong audience. 
Building contractor Haymills, a specialist in constructive conservation, won the £5.3m contract and work began in April 2007; it’s on track to finish at the end of March. “Staying true to the brief has involved retaining as much  original building fabric as possible, not only to preserve the ‘feeling’ of Snape Maltings, but also on the grounds of environmental sustainability,” said Haymills project manager Roger Chapman. This meant timber from the original roofs had to be cleaned, sent off site to be resized and then treated with Arch Timber Protection’s Dricon fire retardant. Trusses that were too large to be removed were treated on site with Tritec preservative.
“The floors and roofs of the old buildings had a lot of very sound boards we could reuse,” said Dillon. “For example, the old kiln timber was quite fragile, but was wonderful – it had aged and darkened and had a slight covering of soot. We couldn’t use it structurally, but it wasn’t going to deteriorate any further in a safe environment and we wanted to use it to recreate the kiln atmosphere in the Kiln Studio.
“Quite a lot of that roof is made up of those old cracked and blackened boards, and we’ve dropped in new timber and stained it to match,” added Dillon. “But we’ve made it quite clear which is the old and which is the new – the process is legible and honest.”

The structure of the Douglas fir-based acoustic boxes

The structure of the Douglas fir-based acoustic boxes

Acoustic focus
The roofs also, of course, had to fulfill another key technical role: “The main spec is acoustic,” said Jonathan Reekie, Aldeburgh Music chief executive, adding that the new areas had to complement the main hall’s performance characteristics.
Arup Acoustics set out the parameters in terms of design and, to an extent, the materials.
“There are various things you need for good acoustics,” said Reekie, “hard, but not smooth or flat, surfaces, and volume. To get an optimum acoustic you need 10m3 of space per musician and we had a target of 4,500m3 [in the Britten Studio]. The length and width were limited by the existing buildings, so the only way was up or down. We went down as far as we dared with the water [the river Alde borders the site] and went up as far as we could.”
While the vaulted roof of the Britten Studio, rising to over 13m, provides the necessary volume, its multi-layer construction prevents sound transferring both in and out.
“We wanted an acoustic shell and it needed to be concrete,” said Dillon. “Forming concrete in a pitched roof  is extremely difficult, but the solution we came to for the Britten Studio was to build a complete roof structure with a steel primary frame [steel trusses] which then had a secondary structure of timber rafters and steel purlins which enabled us to put up a complete layer of Douglas fir plywood sarking onto which we could spray concrete. Then there is an ordinary build-up towards the slate and other finishes on top of the roof. It’s a three-layer sandwich.”
The exposed timber, he added, creates a ”fantastic internal appearance”, but also provides a permanent formwork for the concrete. The latter is then the basis for what is, effectively, a conventional timber roof.
The Kiln Studio roof was a variation on a theme: the steel primary frame comprising a cage of steel rafters, the secondary structure comprising timber purlins, and the sarking onto which the concrete was sprayed, the aforementioned reclaimed boards.
These slight differences in design fulfilled the brief that the buildings have distinct characters, emulating the
organic way the original complex of buildings would have been constructed over time.
“The many different ways you can use timber allows you to do that,” said Dillon.  "The walls also have their part to play in delivering the right acoustics. There is a “rippled” storey level of concrete in the Britten Studio, and above that sit 314 acoustic absorbent boxes, slotted between 150x50mm Douglas fir studs at 450mm centres fixed to softwood timber grounds. The Kiln Studio is lined with 126 boxes.
The acoustic boxes, constructed by Leicestershire-based Neil Burke Joinery as part of a £170,000 contract, are a Haworth Tompkins design specifically for the  project and made from 18mm Douglas fir plywood.
“We were given the technical requirement by Arup Acoustics, but rather than just put up perforated boards like you might see in your local cinema, we decided to find something that was architecturally part of Snape,” said Dillon. “There used to be rails on the old kiln floors into which perforated tiles were dropped in order to spread the heat, so we took that idea and reinterpreted it as a wall cladding. It sounds good, but also has a real architectural narrative to it.”
The studs are fixed to the concrete wall via a 5mm neoprene strip and once the boxes are slotted in they are pinned with wedges and masticked to stop them vibrating side to side. Rockwood insulation between the box and the concrete wall also absorbs sound.
Jonathan Reekie describes timber as one of the best materials available for good “natural” acoustics and Dillon agrees. “It’s very warm, both visually and acoustically,” he said. “And it’s very flexible for making boxes of different depths [and with varying numbers of perforations] to absorb different frequencies – high, mid or base range.”
There has been no attempt to refine the functional appearance of the acoustic boxes – in fact, the internal finish throughout the project is very rustic. Brickwork is left unsealed and part of the Britten Studio’s foyer ceiling has exposed lathes, as if the plaster has dropped away over time.

Avoiding slick
This unfinished finish is in keeping with Snape Maltings and what Aldeburgh Music is hoping to achieve, said Dillon. “We were very aware that if we over-restored it, we could absolutely destroy its character,” he said. It’s a testament to the extraordinarily skilled work of Haymills that an outsider visiting the new structures for the first time is easily fooled into believing they are the original spaces.
“It’s been a massive amount of work,” said Roger Chapman. “The major challenge now the shell is built is the mechanical and electrical work. Ninety per cent of the electrics are at high level and the contractor [Bower Fuller] calculates there is 47,000m of wiring in the roof.”
For his part, Jonathan Reekie is delighted with the
result. “One of the aspects of the project I’m most pleased about is that we’ve managed to recycle gorgeous old timber,” he said. And, he added, the new timber fits right in: “The roof in the Britten Studio is wonderful – and you look at it and think it’s always been there.” As Harry Potter might say, it’s magical.

Old timber sits alongside new

Old timber sits alongside new

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