Des Moines Library by David Chipperfield

19 May 2006

For a European, getting one's head round a place like the US city of Des Moines presents no small challenge. The Iowa state capital has built a booming economy as a centre of insurance services and today is called home by a population comparable in size to that of Newcastle upon Tyne. And yet, it is perfectly possible to walk the length of downtown Des Moines without encountering another soul save for the occasional racoon.

The post-apocalyptic character of the city's street life can in part be attributed to the presence of a 5km-long network of enclosed pedestrian bridges which ties together pretty much every major building in downtown. This so-called Skywalk - I am guessing, named in a fit of Star Wars inspired utopianism - offers an effective foil against the Mid West's often punishing climate but remains the stuff of Jan Gehl's worst nightmares. Even when one has succumbed to its hermetic charms it soon becomes apparent that while cappuccino and bagels are in plentiful supply, any more elaborate shopping is going to necessitate a car journey out to a suburban mall.

At this point, any right-thinking European schooled in notions about the equation of good urban form and social cohesion might reach some less than charitable conclusions. Yet they would do well to pause. Des Moines may be the product of a car culture that has no equivalent on this side of the Atlantic but there are plenty of signs that it sustains a vital and progressive sense of civic life.

I struggle to think of any UK cities of comparable size that have established such a substantial post-war architectural legacy. Des Moines is home to works by both Eliel and Eero Saarinen, including the older man's art centre, which was later extended by IM Pei (very impressively) and subsequently by Richard Meier (considerably less so). Throw in a couple of sleepwalking late Mies schemes and a cracking office block by Bunshaft-era SOM and one arrives at a picture of a city at ease with some of post-war modernism's most stridently abstract adventures.

It also has to be said that not too many cities on this side of the pond would see a David Chipperfield lecture draw in an audience of 700. The setting may have been a little anomalous - Drake University's basketball stadium complete with banners declaring "Go Bulldogs!" - but when he talked there last month, the architect was warmly received by an audience notably more heterogeneous than your standard RIBA crowd.

The talk was scheduled to mark the opening of Chipperfield's own contribution to Des Moines' architectural heritage - the city's Central Library. His building sits at the western edge of downtown, at the urban end of a new linear park which extends for three blocks towards the city edge. The view that first greets visitors to Des Moines is therefore that of a green carpet extending towards downtown's vertical skyline with Chipperfield's low-lying library mediating the transition between the two.

Drawing closer, it becomes clear that the new building is in no hurry to give up its secrets. Purposefully eschewing any articulation of section, or roofline, or of the depth of its facade, or of its multiple corner conditions, or of front and back or of top and bottom, or of any distinction between window and wall, one is left wondering whether this latest addition to his oeuvre offers altogether the best means of supporting Chipperfield's oft-stated ambition to escape the minimalist label.

What is left? Well, perhaps only two things: a plan idea and a material one. The building's aeroplane-like footprint may have been adopted as a punchy logo on all the library's pre-opening promotional material, but as experienced on the ground, it resists any such easy graphic apprehensibility. Rather, the building registers as a purposefully "weak" form.

The shape is dictated by the desire to establish three distinct territories around its perimeter, each of which is associated with an entrance: to the west, the library buckles around the volume of the adjacent Masonic Lodge, fixing a hard-landscaped forecourt in between; to the south, a second indentation allows for the creation of a ramp down to a 30-space underground parking level and a drive-through facility where books ordered online can be picked up, and borrowed material returned; finally, against the park itself, an entrance and an external seating area for a café have been located where two wings of the building draw together at an acute angle.

If the library's strange morphology is in itself hard to grasp, one's sense of it is rendered more uncertain still by the building's material treatment. The cladding around the entire facade takes the form of 4.2m triple glazed panels, incorporating a sheet of expanded copper mesh between the outer panes (Solutions October 14, 2005). From inside, this assembly allows minimally interrupted views of the park while obviating the need for any secondary means of shading. From outside, at least during the day, the effect is all but opaque. Overcast conditions can be unforgiving, reducing the walls to the colour of milky tea, but on clear days the play of overlapping reflections is dazzling. At dusk, when the internal lights are switched on, the opacity of the walls is suddenly dissolved and the interior laid open to view. As in Herzog & de Meuron's Laban Centre - a building that must surely have been a prime source of reference for the design - this moment reveals the wall treatment to be more variegated than it appears during the day. Around half the cladding panels are in fact faced internally in blockwork.

Passing through one of the many entrances, the enigmatic exterior is exchanged for an interior that is lucidity itself. The doors addressing the park and those facing the hard landscaped forecourt close either end of what is essentially a wind lobby. However, the space doubles as a route between city and park - a role that is articulated through its generous scale and the specification of a concrete floor finish rather than the carpet employed elsewhere. From here, the café and multi-functional space housed in the wing to the south are immediately to hand. On the opposite side of the lobby lies the building's nexus - the checkout area, which can also be directly accessed by the entrance doors set in the north elevation.

On both of the library's floors, the freestanding book stacks follow a common north-south orientation. On each level their ranks are parted to allow an east-west access down the full length of the building. At either end of these vistas one finds a freestanding steel stair, painted black to lend it presence against the chocolate coloured carpet and walls painted in kiwi fruit green. Collectively, the shelves are conceived as a solid mass carved into by the wayward geometry of the perimeter walls. In reality, the relationship between the two systems is not quite that absolute.

A series of poché spaces, accommodating extensive back of house facilities, establishes a more manageable internal plan. Where the reading areas are lined by internal partitions those walls follow the geometry of the bookshelves rather than that of the building footprint. In those places where the shelving does approach the external walls it is held sufficiently inboard of the glass to allow seating to be accommodated in the gap between. Here, readers can enjoy views out to the park sat in Chipperfield-designed lounge chairs - a chubby take on Corb's Petit Confort design.

This project had to be delivered to an extremely demanding budget and within the restricted capabilities of the US construction industry. As such, it is an undoubted success, if a somewhat less developed affair than the best of its architect's European and Japanese projects. There is, however, one significant disappointment, although not one of Chipperfield's making - the treatment of the park, newly realised to designs by a local landscape architect. The construction of this public facility represents a major commitment on the part of the city to the regeneration of downtown. It is anticipated that in the near future, condos will be constructed on many of the vacant sites around its perimeter, drawing inhabitants back to the city centre and reintroducing something of the streetlife that the car and the skywalk have done so much to kill off. As realised, the space has been left largely open save for a network of arcing paths, sparely planted to either side. However, one of Chipperfield's early visualisations sets out a very different image of how this territory might be conceived. It densely populates the park with mature trees, which draw in close around the library's walls and approximate them in height.

This description of the collision of quasi-naturalistic planting and rigorous grid-plan offers something of the romanticism of Olmsted's Central Park in New York - if admittedly at a 10th of the scale. It is an image that was clearly key to the way that the design of the library was conceived. The shadows and reflections afforded by such a setting would surely have lent the sheer glass walls a richer phenomenological character than can be claimed. (The glass parkland pavilions of the American artist Dan Graham perhaps suggest something of the fleeting visual effects that might have been achieved.) Equally, one can imagine that such a strategy would afford the interiors a much enhanced sense of their setting within the park.

Yet while the current situation does feel like a wasted opportunity, it is hardly irredeemable. As Chipperfield noted during his lecture it is not too difficult to plant a tree so perhaps his audience might care to take the matter into their own hands. I can only agree: it is nothing less than his building deserves.