A Lean-to to Learn From - Building Design

May 2005

Text David Littlefield
Images Níall McLaughlin Architects

Níall McLaughlin is modest about the form and structure of his latest project, soon to be erected in Hull. “It’s the world’s most basic structure,” he says. He’s probably right – his new Built Environment Centre is designed along the lines of a lean-­to, the sort of thing  kids will knock up to make a den. But that is where the simplicity of this project ends.

The centre is the result of an ideas competition run three years ago by the Humber Centre for Excellence in the Built Environment, and it is finally due to be assembled in May. In 2008 the building will be dismantled and moved to another site, where it will stay before moving on again. This pattern is due to be repeated for the next two decades and McLaughlin has committed his practice to sticking with the structure over this period, with a view to refining and reinventing it each time it changes location.

“What we want to do is use it as a kind of learning building,” says McLaughlin. “Each time we’ll redesign it as necessary. I’d like to think that in 20 years time it might not look remotely like this.” Essentially, the centre is a big wedge. First, concrete padstones are laid out; these are then topped with floor pallettes (filled with ballast to weigh the building down); five large ‘caravan’ modules – prefabricated using standard components supplied by caravan manufacturer Swift Group – are then wheeled into place along one side of this floor plate; and finally, the roof is installed, resting against the top of the caravans and nestled into a transfer beam diagonally opposite at an angle of 34 degrees.

McLaughlin reckons the whole process will take three weeks. The detail of the construction is, of course, more complex than that. But in fact, a lot of the work done by engineer Price & Myers focused on creating a complex structure from the most basic components. Simplifying and ‘idiot-proofing’ the building elements was a major part of the design process.

“This is more like an exhibition stand that thinks it’s a building,” says Price & Myers engineer Tim Lucas, who needed to create a kit of parts that could be easily dismantled without being merely demolished. The structure will generate its own power and is designed (if operated at its optimum level) to be carbon neutral. Apart from all that, this mobile architecture centre is the result of considerable community consultation and local reference – most of its materials, including its blue colour scheme, have been generated locally, and even the use of caravans is inspired by a traditional Hull industry.

One component that is not sourced locally is the chief element of the roof. To look at, the roof is composed of an undulating perforated skin of aluminium – both inside and out. But sandwiched between this cladding is a 100mm-thick polycarbonate product, resting on steel members at 1m centres, more usually seen on warehouse roofs. Sourced from Coventry-based Brett Martin Daylight Systems, these ‘safelight energy saver plus’ slabs of polycarbonate have high insulation properties and a U value of just one. It’s also relatively light and strong, as outlined in the product spec: “(It can) withstand loads typical of inadvertent foot traffic or falling person without damage and without dependence on fixings.”

As a cost-effective, easy-to-assemble, large-span insulated product, which lets the light in, it seemed ideal. The problem with a lean-to, however, is that it might provide an ideal ski slope for overenthusiastic youngsters. This partly explains the presence of the aluminium cladding, which also acts to keep down solar gain, further reduced by orienting the building towards the east, rather than south.

The undulating metal surface will also act as a screen for moving images, to be projected from one of a number of masts adjacent to the structure. A web-cam will film the sea by day and play it back at night. McLaughlin says the rationale for this low-cost cinematography is two-fold: firstly, in playing back the events of the day, it provides the build­ ing with a dreamlike quality; secondly, it acts as a reminder of Hull’s maritime tradition. “At one point, 75-80% of the people in Hull worked on the sea or in an industry related to it. The sea is a part of the collective memory of the city,” he says. “But now older people say that young people don’t even bother to go and look at it.”

There is a further anti-vandal measure at work to protect the roof or to protect the vandals from themselves. A pool of water sits in a stainless-steel trough at at the lower end of the roof, so only the very desperate will want to get on it. In fact, security is a secondary function for this pool – its main purpose is to cool air that can be sucked into the building through a manually operated vent through the roof’s eaves. Warm air is expelled at high level from the main space through vents near the clerestory windows above the caravan modules. Furthermore, the pool is fitted with a sprinkler system which can create a fine mist above the water. Using the principle of the ‘latent heat of evaporation’, by which air is cooled when water becomes vapour, the centre can create its own cool air during the summer months, a technique practised in many Australian gardens.

On the other side of the pool, McLaughlin has sited a grid of 39 masts, 23 of which carry photovoltaic cells, while the rest support wind turbines. Worked up in conjunction with environmental engineer XC02 Conisbee, which also specified a wood-pellet heater for the building, these energy generators should make the architecture centre self-sufficient in terms of power. The building does not have a battery, however, so most of the electricity it generates will be exported to the national grid by day and imported by night (when power is cheaper anyway). “Basically, we’re using the national grid as a battery,” says McLaughlin.

When you add it all up,the elements that go into this little complex make for a striking mobile assembly. In fact, this has proved a problem for the Highways Agency, which needed convincing that the centre wouldn’t be too much of a distraction for drivers on the nearby A63. The wind turbines were a particular worry for the agency, and were also the target of a local ‘no’ campaign, but McLaughlin managed to convince the authorities that this £500,000 architecture centre is no more distracting than, say, an advertising hoarding.

When you think about it, that’s not a bad comparison. This centre has been designed to advertise the benefits of good, progressive and sustainable architecture. When it goes up in May, we’ll see if it does just that.

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