It’s only natural

I admit it – I went to see the University of East Anglia’s Enterprise Centre because of the thatch. Perhaps it’s because I was brought up under thatch; perhaps it’s because I have a soft spot for twisting craft into innovation. Whatever it was, with the words Enterprise Centre in the title and a series of progress shots in my in box I was expecting something more about construction than architecture. Surely when you concentrate on the elements of a project you lose sight of the whole?

I couldn’t have been more wrong. Here is a building that breathes rational humanism. It has a freshness that belies the gimmicky sounding nettle fabric finishes and the double accreditation of Breeam Outstanding and Passivhaus. Within a linear building, on a very plain grid and without spatial gymnastics, it creates an airy, open and generous university route and some straightforward and very likeable offices and learning spaces as well as a building with industry pedagogy artlessly written into its every surface.

There is something easy about this building, although the process was anything but. Perched on red leather Jasper Morrison, cast off after Foster & Partners revisited the campus’ Sainsbury Centre in 2012, Dr John French explains his journey from plant science through working with the Eden Project on a sustainable supply chain to CEO of Adapt Low Carbon, client for this scheme. The steel and ETFE of Eden’s biomes to house plants from around the world made him ask why no-one had tried to build a natural bio-building. ‘There is an intrinsic quality to natural materials,’ he explains. ‘People enjoy their effects, they say it feels and smells nice. I wanted to demonstrate that the natural environment is a viable alternative.’

How to design a bio-building and precisely which materials to use were not in the competition brief. But as home to Dr French’s group, Adapt Low Carbon, and some of the start ups it supports, the building needed to be demonstrable proof of its low carbon, bio-based credo. The group is charged with giving out European money to low carbon start ups, but it also works on turning crops in East Anglia into products and draws together expertise on the built environment. The location on the UEA campus, with its collection of icons by Denys Lasdun, Norman Foster, Rick Mather and others, yet only short miles from the more distinctive flint and timber of Norwich city centre, also prompted French to ask what local architecture was. Clean, clear modern lines for the campus, while reflecting a local vernacular and materials, was what he was hoping for.

So natural, local and low carbon, obviously. Oh, and a design competition over Christmas. Architype director Ben Humphries shudders to remember it. This was a project he knew would be special, he had been watching for it, discussing it with contractor Morgan Sindall. And so December and January were spent finding local suppliers to work with and working through designs, with much of the practice pulled in to help. Given the demands for full figures on embodied energy it was lucky that Architype was one of a select group of practices which could do this as standard. And it had to be costed: French didn’t want a Rolls Royce of a building which nobody could dream of emulating. The eventual design, and its calculations, convinced him and the university’s estates department.

Thatch, a great East Anglian local tradition and export, was top of the list of materials to include. From a distance this is barely perceptible. Humphries talks about creating clean lines. But as you approach the centre gets gradually more fuzzy around the edges, a little hairy, as the cassettes of straw come to life. The harsh machine lines of most panelised systems do not apply – in fact they were nigh on impossible to achieve. There was even a little craft leeway: the corn dollies at window reveals are deliberate throwbacks, as well as a tried and tested solution for finishing tight, highly visible corners. Morgan Sindall senior design manager, Stuart Thompson, had local contacts, including a thatching friend from the local pub, Stephen Letch, who turned out to be the master thatcher of East Anglia.

With a 100 year life cycle built into the brief, thatch’s relatively short shelf life might make it look an unlikely material. But placed vertically it is estimated it could last 50 years. And clipping cassettes of straw on and off is a fairly painless way to upgrade – though rethatching could also be done in situ. It marks a shift, too, in the ability of such craftsmen to earn a living all year round: the six thatchers could all work on their panels inside over the winter. In a slightly more unnecessary gesture, the south-facing clerestories on top of the building have also been thatched, this time in reed. This was a hangover from the original plan to traditionally thatch just the roof (there are few renewable roof materials), before the idea spread to the cladding. The rounded corners here do look incongruously cottagey.

The E plan of the building has a deeply shaded southern elevation in accordance with Passivhaus principles but also gives a relatively solid eastern edge to the campus’s Earlham Park. Along this runs an airy double height space, interrupted by ‘pods’, cross cutting volumes at the first floor, meeting rooms and board rooms.

They are each clad in a different material – reed, earth and clay plaster, nettle fabric – but harmonise around a sense of controlled earthiness. Which, surprisingly, sits happily with concrete slab and circular Foster reception desk of the ground floor.

Main offices and teaching spaces, along the arms of the E, are illuminated and opened up by high-level clerestories over the timber framed corridors. These are wider than they might have been, with recesses for gathering, talking, sitting and working under a bobbly, blown acoustic insulation that gives the rugged sense of roughcast. Working spaces are simple but the timber frame gives them a gentle sense of character, even where the corn dollies are not visible. Needless to say, as a Passivhaus design the ventilation and air handling is at the heart of the project – which you sense as you draw your first breath – but how it works for users is just as important, as the clear controls in each room tell you.

It is the road-side composition that is least convincing. A canopy runs between the two outer wings framing the central limb of the E plan. This is rather bulbous, as a 300-seat lecture theatre might be expected to be, but is made more so by the flint studded attenuation pool. Although this building sits at the gateway to UEA’s campus, and the road is its most visible facade, students will actually approach on foot and be fed through to other – developing – parts of the university as Architype’s masterplan for this section shows. Bounded by hedges, the building sits low in the landscape and, in summer, has only a very modest presence; the thatch is barely identifiable until close up. Craft and construction were intense on this build, with Architype closely involved with Morgan Sindall and the thatching team. But while technically thatch is the most ground breaking aspect of the enterprise hub, it is its combination with the other materials and, most of all, the design that turn this into a really enjoyable building to be in.

Indoor thatching
The 14 different types of thatch cassettes were individually made over winter in East Anglia’s barns and sheds with just the corners and window surrounds completed on site. The scale of the project, the fixings and how to hide the seams of the cassette-edges were the issues master thatcher Stephen Letch and his thatcher colleagues struggled with most.

Letch says that next he would like do a high rise and see thatch stretching hundreds of feet into the air, ideally close clad with thatch to benefit from its insulation properties too.

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IN NUMBERS

£11m total cost

3,400m² gross internal floor area

£2700 Cost per m² GIA

440 annual predicted kg/m² CO₂ emissions over 100 year cycle

Single point delivery based on NEC3

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MATERIALS
Cement 70% ground granulated blast slag cement replacement to ground floor raft slab
Sub base Recycled from local hospital demolition
Slab insulation Isoquick.
Permanent insulated ground floor slab shuttering system.  
Modular off-site fabricated system to minimise on site waste.  Remnants returned to supplier for recycling
Stud work 70% Corsican pine from Thetford Forest, plus Irish Sikta spruce
Main glulam frame Kaufmann, Austria
Glulams UK timber specialist, Inwood. Larch glulams support canopy using locally sourced larch from Brandon Fields Estate, Brandon, Suffolk.
OSB3 boards Smartply. OSB3 boards sourced from Ireland
Blown insulation Warmcell. Blown recycled cellulose insulation to timber panels from South Wales
Rigid insulation to lecture theatre Diffutherm by Natural Building Technologies
Air tightness tape to form continuous air tight layer, SIGA
Roof sheathing Timbervent by Egger
Wall sheathing Sarket by Hunton
Plywood WISA. Spruce and birch ply
Thatch Developed by John Innes. Local straw for external facade cassettes applied by local thatchers. Varieties include Foster Special, Maris Huntsman and Yeoman Wheat
Roofing Local reed roofing from Woodbastwick (edge of the Norfolk Broads) and Saxmundham (RSPB Dingle Marsh)
External grade MDF Medite Tricoya. Cladding panels to external facades external grade MDF with Osmo UV and biocide finish (new UK material trial)
Cladding African Iroko reclaimed from original lab desks in the University’s Chemistry Lab Building by Denys Lasdun
Timba-haul.
Reclaimed English oak timber cladding to lower level ground floor facades from Summerlayton Hall Estate and Holkham Hall Estate
Lime render Baumit. Lime base render system to lecture theatre
Reception desk Re-used from Sainsbury Centre
Timber slat finish Redwood timber from Poland to ceilings and walls internally
Wool wood acoustic boards Troldtekt. Demountable wood wool acoustic ceiling tiles made from low grade softwood and non toxic finishes
Cellulose acoustic finish Sonaspray
Spray on cellulose acoustic ceiling finish made from 85% recycled paper (UK material trial)
Truck tyre flooring Jaymart Flex-tuft tiles. Recycled truck tyre flooring in areas of heavy footfall
Paints and oil finishes Natural Building Technologies emulsion and Osmo. Solvent free natural based paints and oil finishes
Pod surface covering  Camira UK. Hemp and nettle fabric
Earth and clay plaster Natural Building Technologies
Natural reed board Local
Concrete slab Durable high performance ground floor finish – self-finished diamond ground structural ground floor slab
First floor finish Forbo Marmoleum/Ecoscreed. Linoleum, linseed and hessian matting on recycled glass screed
Flooring Noraplan Ultragrip. Rubber sheet
Glazed facade Protec. Triple glazed timber composite windows
External doors Raico. Triple glazed thermally broken aluminium doors
LED lighting and task lighting Fagerhult and Swegon
Rainwater harvesting for WCs Flowstow by Pipex
Flint Locally sourced from Holt

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