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A HYBRID OF BUILDING AND UPTURNED BOAT, THE WIND TURBINES AND COWLS HAVE A NAUTICAL FEEL

BUILDING STUDY

After working for Michael Hopkins and Partners on projects including Nottingham Jubilee Campus and Portcullis House, Bill Dunster set up his own practice in 1999, specialising in low-energy design. Its BedZED development for the Peabody Trust in Sutton won the sustainability award in the Housing Design Awards 2000. The practice is in the process of changing its name from Bill Dunster Architects to ZEDfactory, to reflect the contribution of all its members.

Jubilee Wharf, a mixed-use development in Penryn, Cornwall, is the latest of ZEDfactory's schemes that dramatically reduce fossil-fuel consumption and CO 2 emissions. While not yet generating all its energy needs, with future upgrades it will do so.

Nevertheless, some key components (such as wind cowls) are improved versions of those on BedZED; and like that seminal scheme it includes residential and workplace units, potentially diminishing the need to commute. It furthers other aspects of the green agenda, contributing to community life and drawing attention to the ambient energies it harvests. It thus provides an enhanced quality of life essential to both the green agenda and its popular endorsement, as well as a sense of connection with other people and nature - psychic satisfactions which, it might be argued, alleviate the desperate drive to consume.

The building is prominently sited, almost as a gateway to Penryn. It is conspicuous from the harbour creek and the road from Falmouth to the east as it terminates a waterside row of nondescript commercial and semi-industrial buildings. These extend north-west along Commercial Road from where it is met by the town's main street, which slants down the hillside from the west, its final stretch offering views of the harbour, the new building and its wind turbines. The site had been derelict for a decade, latterly even cleared of its sheds, the planners having rejected a previous owner's proposal for mixed-use development when Andrew Marston bought it in May 2002.

Project, client and architect seem exactly matched.

Marston is that rare client, committed to long-term and community benefits. Five generations of his family have been involved in building, property and hotels. When he bought a 125-year lease on the site it was to create a development that would bring income to further generations of his family, and help regenerate Penryn. Hence his commitment to diminished running and energy costs, and 'future proofing' through later upgrades.

Marston initially envisioned craft studios around a communal courtyard. Having been a craftsman himself, he knows crafts are important to the Cornish economy and that much that is produced goes directly to clients elsewhere. Cornwall and its craftsmen could benefit if their products had greater local presence.

Talking to townspeople, he also established the need for a nursery school, a multi-purpose hall (for yoga and so on) and offices for community organisations. All these elements, which constitute about half the development, qualified for grants from the Objective One programme of the European Regional Development Fund (applicable only to Cornwall and Wales in the UK) that covered about a third of their construction costs. Local grants were also used for some community elements.

Marston interviewed other architects before choosing ZEDfactory, appreciating its ethos and the community spirit and loyalty to BedZED among its residents. By now the site was subject to a local masterplan stipulating a block fronting the south-facing edge of the wharf with parking behind. But the parking wasted a prime part of the site, and the wharf edge is subject to regular flooding. (Dunster's rejection of the masterplan and the unconventional look of the building would provoke initial resistance from the planners. But then the 2003 New York blackout, followed by a limited power failure in London, highlighted the timeliness of his proposals. ) ZEDfactory proposed two blocks framing a sheltered court looking across the creek, the ground floor of the blocks and the court raised by 1.5m, leaving a strip along the historic quay edge at the existing level. Along the south-facing quay is a twostorey block with community facilities at the ends and rooms with plumbing (kitchens, WCs and changing rooms) in between. On the ground floor, against a ramp up from the street, is a Sure Start nursery with a south-facing, roofed play space beyond. At the block's other end is a café-bar with a raised timber deck outside enjoying sun and splendid views. Above the nursery are the offices and above the café is the large hall.

The four-storey block on the other side of the court has two levels of studio workshops below maisonettes, which Dunster proposed as part of a more intense development than Marston had in mind. (These are rented, though Marston lives in one and another has been sold to his mother for holiday use. Marston's wife, Alice, runs the café. ) The workshop windows on the court can serve as shop fronts. Ground-floor units are accessed off the court and have a goods entrance from the rear parking court.

First-floor units are along a gallery overlooking the court. This gallery is reached via a bridge from stairs set into the lower block.

The same route provides access to another stair behind the taller block; this climbs to the access gallery to the maisonettes, but does not descend to the ground. These elongated access routes help animate the court, to which the bridge defines an entry portal.

The maisonettes command fine views up and down the creek and have evolved from those at BedZED. Airtight and super-insulated (with 300mm Rockwool cavity insulation and high-performance windows), they have high-thermal-inertia concrete floor slabs and inner leaf, and are ventilated by tracking wind cowls with heat exchangers. (The cowls are squatter than those at BedZED, and are angular rather than curved, with triangular flashes of colour that seem to be aptly nautical. Partly because of the corrosive sea air and high coastal winds, they also have more robust bearings, taken from a Ford Mondeo wheel hub. ) Both floors are fronted by a glazed sunspace, part of it double height, that helps warm the units in winter. The lower level opens out on to a balcony; and on the upper level inward-opening French windows turn part of the space into a balcony area.

The workshops are similar to the maisonettes in construction. But with less solar gain, they are heated in winter by low-temperature underfloor heating. (There is underfloor heating in the community spaces and maisonettes, but it hardly needs to be used. ) Ventilation is by side-mounted units with electric fans.

The shaping of the cross section of both blocks was crucial to ensure sheltered conditions in the court and was refined by computational fluid dynamics (CFD) analysis. The lower, down-wind block is designed to lift the wind up and over itself, the court and the taller block without turbulence. Thus its south wall leans back and sweeps in a curve into the roof, the whole supported by laminated timber beams and clad externally, like all the roofs, in durable zinc. (Because of its shape, much of this block is of lightweight construction with thermal mass provided by the concrete floor slab. ) The upper floor extends out to shelter a walkway to the café, and the roof eaves reach yet further to guide wind across the court to where the taller block helps maintain a stable high pressure within the court. The southern edge of this higher roof pitches down to help entrain the air and provide a sunny surface for the solar heating panels - and for future retro-fitting of photovoltaics as their payback period diminishes.

The solar panels provide hot water for half the year, and are supplemented in winter by a wood-pellet biomass boiler. On the quayside, in front of the lower block, stand the wind turbines, their masts mounted on hinge plates so they can be lowered on to the quay for easy maintenance. These are not the highest performance turbines available, but are robust and safe, the blades furling rather than speeding up in very high winds. Provision has been made for each maisonette to be fitted with its own rooftop micro turbine. Along with the photovoltaics, the building should then generate all its energy, if not more.

Where possible, local materials and labour were used.

For instance, some walls are clad in locally grown western red cedar, and external soffits are untreated local larch. All timber is Forest Stewardship Council (FSC) accredited as being from fully sustainable sources, including the durable imported red angelim of the café deck. Other materials, such as the wood floor in the café and the ceiling in the hall, are recycled. So too are what were granite kerbstones, used to consolidate the edge of the old quay.

Construction had its problems. Piling encountered old walls from earlier quays (damaging the rig) and a sewer not aligned as shown on surveys, leading to a 10-week delay. With half the building funded by various grants, there was reluctance to advance detailed design development until these were certain.

But, once granted, construction had to start quickly, without time for a full bill of quantities. Such problems, together with those of contractors encountering unfamiliar technologies and their knockon effects, led to a 67-week build time, overrunning by 32 weeks: and to cost overruns of £600,000 taking the budget to £3,600,000.

Marston accepts these with good grace, attributing much to the funding process and recognising that he has a sound long-term investment. The £1,700/m 2 gross internal cost is competitive for such a complex mixed-use scheme with a low-carbon specification and microgeneration.

Appraisal of this sort of building should wait until it has settled into the life of the town and the performance of its environmental systems has been monitored. Yet already when visited after being open only half a week it was becoming lively; the bicycle shop on the street, the workshops and the hall were all busy, and the café was bustling. The location of the various functions clearly fulfils Dunster's design intent of 'having the right activities happening in the right place at the right time'.

The building may be unconventional to look at and resembles no neighbour. But, evoking a hybrid of building and upturned boat, with the blatantly functional elements of wind turbines and cowls recalling similar nautical elements, it is apt to its site.

It responds to the road bend it sits on, terminates the buildings behind and steps down to the empty wharf in front of it, and the roof extending over the ramp is a generously welcoming gesture. The courtyard is well sheltered from wind, and much of it from the rain too. Already it has attracted interest for a craft fair and could host farmers' markets and so on. Trees have yet to be planted and the court has been left deliberately to see what demands are made on it and how it might be finished, perhaps with the placing of benches.

If the design raises a quibble, it is that no uses spill on to the south-facing quay, and the backward slope of the wall feels unwelcoming. Despite the flooding and the protection offered against the corrosive, spray-laden winter winds, this seems a missed opportunity. Apparently the café deck was to have extended a little way back along the quay, but the space was needed to lower the end turbine. Besides, as Marston says, it is apt that the quayside seems part of a public promenade.

Jubilee Wharf is clearly another milestone in green design and a tribute to the dogged commitment of client and architect.

Critics and architects, the latter feeling guilty about not making similar commitments, should not carp about time and budget overruns that will not matter in the long term. This is no fashion statement, but the inevitable future, to learn from and emulate - now made easier because Dunster has ensured the ready availability of the technology.

Costs Cost analysis based on gross internal floor area.

Costs refer to projected final account SUBSTRUCTURE Foundations/slabs £175/m 2Piled foundations; ring beam; damp-proof membrane/ radon barriers; in situ suspended ground-floor slabs SUPERSTRUCTURE Frame £90/m 2Building one - heavyweight blockwork walls.

Building two - blockwork, steel structure and glulam Upper floors £83/m 2Building one - 150 hollowcore precast concrete planks, heavyweight blockwork internal leaf walls.

Building two - blockwork internal leaf walls (to first floor), precast hollowcore planks, timber to first-floor Roof £68/m 2Building one - precast hollowcore planks; 300mm Rockwool insulation; FSC timber frame; Klober breather membrane; 18mm FSC wbp ply; zinc roof on drainage layer (includes future-proofing ridge turbine spurs); and upstands to unistrut. Building two - timber frame; wall into vapour-permeable barrier; 300mm Rockwool; Klober breather membrane; 50mm air gap; 18mm FSC wbp ply and zinc roof on drainage layer Staircases and elevated walkways £90/m 2Building one - steel stairs and balconies with concrete infill; internal FSC softwood staircases.

Building two - steel balcony and stairs; marine hardwood red angelim FSC decking; concrete stair External walls £152/m 2Building one - heavyweight blockwork with FSC western red cedar cladding or self-coloured lime-cement render. Building two - blockwork with self-coloured lime-cement render; timber walls with FSC western red cedar cladding Windows and external doors £71/m 2Softwood timber doors and windows with argon-filled double glazing and ironmongery Internal walls and partitions £32/m 2Softwood partitions with plasterboard and skim Internal doors £21/m 2Softwood solid-core doors and ironmongery INTERNAL FINISHES Wall finishes £51/m 2White eco paint; exposed FSC softwood timber trunking; FSC softwood skirtings and architraves Floor finishes £25/m 2Building one - residential high-wool-content carpet, ceramic tile; natural lino 'Marmoleum'; epoxy paint.

Building two - ceramic tile, reclaimed timber floor to bar; FSC oak floor to hall; natural lino 'Marmoleum' Ceiling finishes £13/m 2Building one - residential timber FSC softwood trunking; white eco paint. Building two - FSC softwood timber trunking; white eco paint; plasterboard with skim; reclaimed floor boards with class 0 finish FITTINGS AND FURNISHINGS Furniture £17/m 2Building one - kitchen units and workshop tea points. Building two - kitchen units

SERVICES Sanitary appliances £31/m 2WCs, showers, bath tubs and sinks Mechanical installations £242/m 2Building one - wood-pellet boiler and silo; solar hot-water panels with pipework and associated tanks; wind cowls; ductwork and heat-exchange ventilation units; underfloor heating pipework and manifolds. Building two - solar hot-water panels with pipework and associated tanks; wind cowls, ductwork; underfloor-heating pipework and manifolds; wind turbines Electrical services £96/m 2Boat facility electrical points; electrical installations for mechanical installations; low-energy internal and external light fittings Lift installations £12/m 2Building two - disabled lift and dumb waiter EXTERNAL WORKS Landscaping, ancillary buildings, drainage £165/m 2PRELIMINARIES AND INSURANCES Preliminaries, overheads and profit £278/m 2

Cost

summary Item Cost per mless than or equal to (£) Percentage of SUBSTRUCTURE 175 SUPERSTRUCTURE Frame 90 Upper floors 83 4.8 Roof 68 Staircases 90 and elevated walkways External walls 152 8.9 Windows 71 and external doors Internal walls and partitions 32 1.9 Internal doors 21 1.2 GROUP ELEMENT TOTAL 607 35.8 INTERNAL FINISHES Wall finishes 51 3.0 Floor finishes 25 1.5 Ceiling finishes 13 0.8 GROUP ELEMENT TOTAL 89 5.2 FITTINGS AND FURNITURE 17 1.0 SERVICES Sanitary appliances 31 1.8 Mechanical installations 242 14.1 Electrical services 96 5.6 Lift installations 12 0.7 GROUP ELEMENT TOTAL 381 22.3 EXTERNAL WORKS 165 9.6 PRELIMINARIES & INSURANCE 278 16.2 TOTAL 1,712 100.0 Cost data provided by David Hibbert, James Nisbet and Partners Credits Tender date October 2004 Start on site date November 2004 Contract duration 23 months Gross internal floor area 2,100 m 2Form of contract GC/Works/1 Total cost £3.6 million Client Robotmother Architect/project manager ZEDfactory: Matthew Hoad, Asif Din, Leigh Bowen, Susan Venner, Bill Dunster Main contractor Midas Construction M&E engineer Arup Structural and drainage engineer Mark Lovell Design Engineers Quantity surveyor and planning supervisor James Nisbet and Partners Subcontractors and suppliers M&E Project Heating; structural steelwork CSS; metalworks Mid Cornwall Metal Fabrications; carpentry Tim Luscombe Construction; masonry NJ Curnow Construction; groundworks Shaun Conway Baker Groundworks; roofing Boss Metals; decorations Kincaid Decorators; plastering/render Keith Towsey Plasterers; boiler Wood Energy; cowls ZEDfabric; wind turbines Proven Energy; FSC hardwoods Eco Choice; reclaimed materials BioRegional Reclaimed; exterior timber Tino Rawnsley Woodland Products; windows and doors Rationel; aluminium flashings Jade Aden; FSC timber and main materials Jewsons

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