Or, how an English contractor went west to build a visitor attraction and found itself immersed in the dangerous and fascinating world of marine wildlife.
Not many contractors can boast that they've built an estuary on the roof of a restaurant. There are probably fewer still that can lay claim to constructing a cliff on which auks will nest. But in the Cornish holiday resort of Torquay, that is exactly what main contractor Dean & Dyball has done as part of the construction of a visitor attraction called Living Coasts.

Living Coasts is Paignton Zoo's latest venture, and the theme is coastal habitats. The £7m attraction's collection of tanks and pools will be home to penguins, puffins, seals, and otters. The roof will provide a habitat for seabirds, and an old sea container will offer accommodation to a family of black rats. The entire development will be turned into a seabird aviary by a vast net, supported by masts up to 22 m high. "It will be Devon's answer to the Eden Centre," says Philip Knowling, Paignton Zoo's publicity officer.

The attraction's slogan, "life on the edge", is appropriate given its location at Beacon Cove, perched at the end of a rocky promontory that marks the boundary of the Torquay waterfront. A narrow, car-lined road leading into town provides the only route for deliveries to and from the site.

Life on the edge would fit Dean & Dyball's experience of building the attraction. To begin with, there isn't a lot of call for estuary roofing in this country, so the contractor had a bit of a learning curve. Then there was the complexity of the building and its precarious location. "Space is very, very tight on this site," says Andy Haill, Dean & Dyball's project manager. And it is not just space that is at a premium, time is short, too: the attraction opens for visitors on 14 July – just in time for the school holidays. This means the contractor has to be clear of the site by 16 May to give the animals time to acclimatise before they meet their public.

The building the animals will be moving to has been designed on three levels . On the lowest is the entrance foyer with its beach hut-style ticket booths, a subterranean corridor lined with viewing windows to allow the public to see the underwater behaviour of the seabirds and mammals, and – of course – the souvenir shop. On the next level up is the attraction's restaurant and the administration offices. However, buildings only cover part of this level. The remainder of the site is open to the elements; the otter, penguin and auk pools are situated here. The rooftop estuary is perched on top of the restaurant's roof, and above it, the netted aviary cloaks the whole development.

The contractor is now rushing to meet the May deadline. The last of the netting masts have been craned into place and installation of the net has begun. On the roof of the restaurant, beneath the towering masts, soil and sand are being sculpted to form a gently contoured estuary landscape complete with small hummocks. The hummocks will form a series of small islands once the rooftop landscape has been flooded with water.

Construction of the restaurant itself is complete and fit-out is under way. Beneath the restaurant, the souvenir shop is about ready to receive its stock of goodies. To the east of the restaurant block, where the structure steps down to follow the contours of the promontory, work is pressing ahead on construction of the series of concrete-walled tanks that will be home to the penguins and South American fur seals.

The site's clifftop location and its limited access have dictated the construction strategy. "Programming has been an absolute nightmare," says Haill. Before construction could commence, Dean & Dyball had to demolish the Coral Island entertainment complex – a derelict 1960s eyesore that occupied the site. Not everything was demolished, however; the contractor retained some stone arches that were part of the Victorian Spa that first occupied the promontory, and these will be incorporated into the souvenir shop.

With the site cleared, the first part of the attraction to be built was the building's structural frame. Two different types of frame have been used: on the eastern side, a steel frame supports the restaurant and shop, whereas insitu cast concrete has been used for the part of the building containing the pools and tanks. Mike Shepherd, Dean & Dyball's south-west region business development manager, says: "Steel was used because it was too risky to dig footings for the concrete structure near the Victorian arches."

The tight site meant that the steelwork erection had to be programmed carefully. Working from the site's wave-lapped western perimeter, the steel frame was constructed in four phases, working progressively toward the site entrance. "We put up the steelwork in such a way that the crane was able to reverse off the site as it went," says Haill. The promontory's exposure to strong winds meant that there were days when the crane could not be used, which added to the challenge faced by the steel erectors.

As the frame was nearing completion, work started on the concrete structure and the animal tanks – "a very complicated insitu reinforced concrete structure", according to Haill. Dean & Dyball had initially planned to subcontract the works, including the animal tanks. However, the design was under development as the contractor was agreeing a maximum price for the project under the PPC2000 partnering contract. So, instead of subcontracting their construction, Dean & Dyball opted to strengthen their control of costs by constructing the tanks themselves.

The fact that water features predominate in all the main attractions meant that waterproofing was vital. The task of putting a raincoat over the superstructure fell to waterproofing specialist Tilbury Douglas. Tilbury Douglas is a licensed installer for the three-layer membrane system, developed by Erisco-Bauder for the task. To ensure the integrity of the waterproofing layer, every penetration through it had to be carefully detailed. "It was quite a complicated detail; everything fixed to the roof, every screw or nut had to be encapsulated," explains Haill.

Finding time for the waterproofing team was also quite a challenge. Entire areas of the site had to be cleared of trades and equipment to make a space large enough for them to work on a complete section of the structure. "The work had to be phased from west to east across the site," recalls Haill. Scheduling also had to allow time for the contractor to test the integrity of the membrane before it could be signed off for handover. "The whole operation took four months to complete," he laments.

With the membrane finally in place, Dean & Dyball were able to commence the landscaping. This involved trucking in six different types of mud from Exeter, shingle from Plymouth and clay from Newton Abbot, all of which had to be checked to ensure that it was free from contaminants. To keep the loading on the structure within limits, the depth of landscaped soil had to be strictly limited to 1 m using polystyrene void formers as a crudely sculpted base. Even so, the contractor estimates that diners in the restaurant have 800 tonnes of mud suspended over their heads.

In addition to sculpting the soil into a passable imitation of an estuarine landscape, Dean & Dyball also had to oversee the construction of that cliff for the auks to nest on. Transporting rocks to the site, assembling them into a cliff, and then carving them into nesting sites for the auks was not an option. Instead, specialist "rock" creator Rockthemes formed realistic cliffs using a series of glass reinforced concrete mouldings – taken from real rocks – which were bolted together. Skilfully, Rockthemes has arranged these false rocks so that their strata line up with the strata of the rock on which Living Coasts is being constructed, giving the impression that the rock has punched through the structure. The rocks will also line the animal pools to give them a more naturalistic appearance.

With the rock contractor putting the final touches to the cliffs, the masts were craned into position ready to support the aviary net. The architect, Derek Elliott, wanted a flat-topped aviary, without sags in the net, which meant its supporting cables had to be maintained under tension. Net contractor Vector Special Projects devised a simple solution – one that would not blow the project's budget but would allow tension in the nets to be maintained as their steel supporting cables stretched. Its answer – which must have been inspired by the site's seafront location – has been to stand the steel masts in pots filled with sand. When the net needs tensioning, supporting cables are slackened enough for the mast to be lifted, so that more sand can be added to the pot. The masts are then replaced, the cables re-tensioned and the aviary net returned to its stretched form.

The installation of the nets is now under way ready to form the seabirds' enclosure. In a few days' time, before the team leaves the site, Dean & Dyball will flood the rooftop estuary and fill the pools ready for their residents.

But, even after the contractors have left, there will still be a reminder of their presence here.

One of the displays explains how black rats have attacked seabird colonies around the world by eating the bird's eggs. The display shows how the rodents have travelled around the globe as stowaways on ships. To help create the nautical theme the rats will be housed in an "old shipping container" – actually an old tool store donated by Dean & Dyball. Needless to say, the company's logo is still emblazoned on the crate – but given the challenges the contractor has had to overcome in building this attraction, surely they can be forgiven a little self-publicity.

Where the idea came from

“It all started over a beer in Shanghai,” recalls Derek Elliott, architect of Living Coasts and principal of Kay Elliott Architects. He was in China overseeing the construction of his latest scheme, the Ocean World Aquarium in Shanghai, a few years back. Elliott was sitting in a bar with an acquaintance from IAT, an aquarium water treatment specialist. The conversation centred on the spectacular aquarium projects being built overseas. “I said, ‘We’re doing all these stunning projects, but there is a great site in my home town of Torquay – come and have a look at it’.”

Elliott started his architectural firm Kay Elliott in the late 1970s, and one of his early projects was a cafe bar at Paignton Zoo. “After that, they let me loose on animals,” he says. His practice quickly become a recognised expert at designing animal habitats, and has jobs in Bristol, Helsinki and Holland in its portfolio. Dismayed by the wasted opportunity of Beacon Cove, Elliott spent £10,000 of his own money to have it surveyed and to produce a business plan. His conclusion was that there was no point in redeveloping the cove unless access to the promontory was improved. Elliott’s studies lead him to challenge the council’s proposals for the site, which he says included a scheme for a Harry Ramsden’s fish and chips restaurant. Eventually, Elliott’s proposal for an aquarium was one of nine submitted to a focus group, where it proved the most popular. However, there was already an aquarium in Plymouth – so in 1998, Living Coasts was conceived. Living Coasts is only part of the redevelopment of Beacon Cove. The £13.5m scheme includes a bridge over the adjacent marina to improve access, the construction of a pub–restaurant near the marina and the partial conversion of a car park into business units.