Established in 1990, Glenn Howells Architects has offices in Birmingham and London. Key buildings include The Dream Factory in Warwick, the UK's first purpose-built theatre for young people; the Market Place, an arts centre for Armagh City & District Council; and Timber Wharf, Manchester, a residential development for Urban Splash. Current projects include the conversion of The Rotunda, a Grade II-listed Birmingham landmark, into 234 apartments; and the Aspex Art Gallery, at Portsmouth's historic docks.
Three domes, sinusoidal, ultra slim in elevation. The Savill Building in Windsor Great Park has, with some elegance and a sheepish nod to Brunelleschi, lifted the timber gridshell into the mainstream of architectural practice in Britain. The building is referred to by its architect Glenn Howells and the royal demesne's Deputy Ranger Philip Everett as 'iconic'. This serially unfortunate term reflects its brandmark qualities, but this is not bling, nor even Duchy Original, architecture. The design process was exploratory, the commissioning was an act of faith, and the detailed outcome was not predictable.
A chance has been taken here, although there is no hint of this. The Crown Estate Commissioners' £5.3 million investment seems akin to a blue-chip each-way banker at Ascot. More than a decade since Frei Otto, Richard Burton, Buro Happold and Edward Cullinan created Britain's first radical green timber buildings at Hooke Park, and three years after Cullinan and Happold contrived the Weald and Downland gridshell in Singleton, this structural form has been rendered credible in Surrey; it is expected to lift annual visitor numbers by a third, to 450,000.
To the Modernist eye, the Savill Building makes the structures at Hooke Park and Singleton appear, respectively, arcanely pagan and charmingly eco-warriorish. The response is questionable, but the reason for it is plain to see. While the Savill Building's canopy dominates the elevation like a flattened, silvery arabesque, scribed by an artist with languid asymmetry in mind, its secondary features - glass, steel and brick - are not in the least recessive; they want to be noticed, their difference is accentuated.
The Modernist geometry and materials meet, and have reached hybridised agreement with the oak, plywood and Kerto LVL, crafted into the canopy section by Green Oak Carpentry.
This fusion of materials and typologies, which looks pretty seamless in the finished building, was hazardous during the design process, the on-site changes in detailing and - to put it mildly - the budget adjustments. The building's insouciant cadences have effaced the occasionally tortuous truths of its erection by main contractor Verry Construction. The Savill Building is a British first, and firsts do not come cheaply, or easily. Everett notes that Howells' original canopy proposal was too big and expensive, and that on-site negotiations were often 'interesting'.
It is also clear from the experience of the Savill Building that, in the medium term, fusing timber gridshells with the usual suspects of the Post-Modernist pattern book will remain exploratory. The combination of materials and the ambitious extension of previous gridshell geometries depended upon moments of ad hoc democracy in decision making, which characterised the construction process in a fillet of countryside whose idylls have never been associated with architectural experimentation.
The Great Park covers 2,020ha to the south of Windsor.
More than half of this is forested and the public areas are mainly woodland or open grassland. The Crown Agents' design brief required that timber from the park be used where possible, so oak and larch were duly sourced: the oak was used for the canopy's outer rainscreen, flooring and key non-structural external features; larch suited the laminated grid lattices and their blocking pieces.
The park still seems imbued with a faintly Edwardian ambience: Smith's Lawn, Blacknest Gate, the Valley Gardens and Virginia Water are still the purview of the Ranger, the Duke of Edinburgh. The origins of Virginia Water's modern expanse can be traced to 1621, when the expertise of the Dutch engineer Cornelius Vermuyden stemmed a breach in the Thames embankment at Dagenham. Vermuyden's parkland-drainage scheme at Windsor was approved by the Duke of Cumberland, who was the third son of George II and the Ranger responsible for transforming this swathe of Surrey bogland into much of today's park.
The Savill Building resets the whole experience. The successive beech arbours that crowned the garden were unsuccessful as scene-setters and the latest, planted after the 1987 hurricane, was felled to open up space for the Savill Building. The original visitor centre will now be demolished. Howells has achieved an ordered sense of procession by familiar means. The approach to the building is from the car park on the northern side, which allows a cursory glimpse of the canopy; it is the delicate-looking edge we notice, but the fuller form remains obscure. This is the result of a kind of compression - the only compression in the programme, which otherwise recalls Norman Foster's charmingly idealised sketch for Stansted Airport: you walk in, you walk straight ahead, and you get on the aircraft.
Here, you walk in, you walk straight ahead, and if you wish to avoid retail or information hazards, you leave the building across a wide stone-flagged terrace (there is still time to falter and sit down for tea, or buy impossibly healthy-looking plants) and debouch straight into the park's first grand declivity. The initial compression is achieved by two grassed and juniper-planted berms, either side of the entrance, that draw the gaze to a central point; the berms also preface the wave-form of the canopy, which can only be fully appreciated from the southern side of the building.
Beneath the canopy, Howells has kept display and other functional structures to a minimum - he thinks of them as scattered items of furniture in a pavilion, rather than as forceful demonstrations of internal architecture. It is the underside of the canopy that engrosses, bringing to mind the designer Thomas Heatherwick's remark that 'the eye likes to reach out and touch things'. That the eye does so here is due to the canopy's scale, sense of movement and detailing.
Howells describes the canopy as 'like a duvet being fluffed up'. The middle-class connotation must be countered by the fact that the latticing - the geometry compressed here, extended there, and always veering asymmetrically - also resembles a giant sheet of tripe made of wood. The nature and effect of the architecture is produced by calculated combinations of material, and they are founded on the details of this duvet. The pairs of blocking pieces dividing the larch chords are discontinuous: the gapping accentuates the sense of craft and handiwork, and establishes a certain rigour, evident in the minimised steel and timber sections.
The language even tallies with the steel sliding pin-joints that connect the top transoms of the full-height glazing along the building's southern facade to the canopy.
Buro Happold's contribution was of critical importance.
The practice's gridshell expertise dates back to its involvement in the groundbreaking expression of Frei Otto's plastic 'hanging chain' gridshell at Mannheim. At Windsor, the gridshell was erected on raised scaffolding, covering the 90 x 25m plan area of the canopy, then dropped in a series of precisely cascaded 'adjustments', relating to 200 datum points; these, in turn, referred to a single arced setting-out line, in plan, near the building's centre line. In its pre-dropped form, the gridshell was a symmetrical lattice with a 1m grid, made up of 80 x 50mm larch sections.
The grids were originally to have been triangulated with steel cables. Fortunately, this materially clumsy idea was superseded by something more self-effacing. Schauman birch plywood was applied to the shell's upper surface - and there is something truer, simpler and less agrantly über technik about the canopy as a result.
A surprisingly oppy 'spaghetti' of oak sections - long lengths that were finger-joined on site in poly-tunnels - was attached directly to the raised seams of the aluminium water barrier, fixed to the gridshell's plywood sheathing.
A key issue was the canopy's load concentrations, and their dispersal. This required a gear-change in timber materials:
LVL sections were bolted to the edge sections of the gridshell, then connected to in-plane steel fins on the structural ring-tube, girdling the undulating edge of the canopy. The tube, welded on site in 12m sections, was just 2mm out when the two ends were joined - a 'fantastic achievement, ' according to Happold's project engineer Richard Harris.
How easy it all looks from the south: the silvering canopy; the thin mullions and the peculiarly satisfying wall - made in local brick the colour of a port wine bibber's nose - which curves gently through the northern side of the plan to create back-of-house spaces between the main volume and the berms. Even the four quadruped steel supports for the ring-tube on the south side manage to present themselves as graphically secondary to the gestural primacy of the canopy. However, Glenn Howells admits, ruefully, that he had wanted to paint them black rather than pale grey. What a very close call, for he would have then rendered the whole facade, with its darkened glass panels, too dense to carry through the sense of craft that defines the Savill Building. His recollection that Brunelleschi always coloured architectural structures grey in his drawings gives this important about-turn a certain wry authority.