Shingle Style

Municipal swimming pools are rooted in our consciousness, splashes echoing, slippery tiles and hair in drains. Worthing had one of those – Aquarena – built in the late 70s. But now, ­funded by loans raised on Aquarena’s future sale and development and built alongside it, the seaside town has a new municipal pool. It was commissioned and designed with start­ling confidence, given the straightened times, and it’s finished to unexpectedly high quality given the norms of public procurement. 

The ‘design’ solution was initially up against a shed extension to an out of town leisure centre, but councillors plumped for more central development along the seafront. That brought an obligation to spend money on a high quality design that would do justice to the prominent site between the pebble beach and the main Brighton Road, alongside the listed Beach House and grounds. As recession kicked in, 109 practices submitted entries to an RIBA competition, and Wilkinson Eyre took the prize. 

Real estate went down and the budget followed, dropping from £22m to £17m; then a slimmed down design was accepted at £19.7m which came in at £3600/m2. December 2010 was identified as a time when tenders were likely to come in extremely low (which put a stop to endless discussions about minor ­details such as installing pirate ships and so on). Council leader Paul Yallop decided to ride out any criticisms and just dive in. 

The pools are housed in one curving volume with a timber box alongside for gym and studios. From the coast road the building appears with a VitraHaus-style outline of the form against picture windows – a drawing of its section (the curve has the elegance of a ­Hadid roof but with more structural sense). 

As a large volume there was the danger that side-on it would appear monolithic – pot­entially just a replacement for Aquarena as a stolid book end to the beach. But the rhythm of the copper panels on the west elevation plays a large part in ameliorating this effect – as does the facade in the way it flicks out to pick up sun from the north in mesh-clad extrusions. The pools opens towards the sea, sweeping visitors along in a curve towards the beach. The sea frontage – glazed spa, seagull-populated paddling pool onto listed Beach House colonnade, and projecting timber box – is least convincing, lacking presence and access. This is only partly a victim of a lack of funds that has delayed the addition of a beach house café facing the paddling pool to create a phase two.

The discussion of economies came at the start of the design process, with the ­entrance pushed into the centre of the building in a way that would minimise circulation space and staff to control it. You wouldn’t think it, but keeping volume to an airy minimum was also critical. Happily, high tech pool floors nowadays can help to reduce heating loads, by not only moving to allow different depths but also acting as pool covers. When I visited the grass outside was still recovering having been dug up for the ground source heat pumps.

 

There are three pools in the complex, set in a line from road to beach. But the building form, its glazed end opening up on the beach, and its structural twist, ensure all is not ortho­gonal. ‘It would have been deadly dull if it was all straight lines,’ says Wilkinson. ‘You don’t win a competition with ordinary,’ he adds. The main steel beams read as a sinuous ­ribbon structure – which perversely and ­beautifully runs the 50m length of two pools as far as a glazed partition. Each steel curves in two ­directions opening up towards the sea, braced by good looking structural timber cassettes in the 8-14m distance between the long beams. The practice describes the structure as ‘experimental’ and the engineer admits to a certain amount of ‘unusual load paths’. 

Once you are in the pool swimming, the roof and eye level view are all. So the twists of the beams play a great part in the delight in the building. Deck level (not quite infinity-style) pool edges and low level glazing borrow a bit of the park for the pool. Hopefully the trans­parent glass will survive swimmers’ sensibilities here as it has failed to do at other pools. ‘We wanted the architecture to be as light as possible,’ says Wilkinson. ‘That is what transforms swimming from an exercise regime.’ 

 

 

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STRUCTURE

The pool hall was an exceptional challenge. Its roof is supported by two 80m long continuous steel beams with a trapezoidal box section. They have a 50m clear span and curve both in plan and elevation generating large forces that create torsion in the box beams. These are restrained against twisting by steel frames hidden within the roof profile at the hall-ends. Minimising intermediate structural requirements, this permits an uninterrupted timber clad soffit between the main feature beams, drawing the eyes to towards the open sea. Parametric design tools were used to create the main curved beam geometries and aid with the setting out and interfaces with the glazing.

The long facade, which takes the brunt of westerly gales, has an ingenious stability system. Wind forces take a convoluted path across the complex roof profile back to the main concrete frame, leaving the feature glazed end facades free of stability bracing.
Matthew Palmer, Structures, Aecom

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IN NUMBERS

£19.7m
project value

4700
m2 gross area

3600
£/m2 cost per m2 

111
kg CO2/m2/year calculation

Design Build JCT 2011
form of contract

Very Good 
Breeam rating