Stonehenge Visitor Centre, Wiltshire, UK – a world heritage
The design concept at the heart of the new Stonehenge visitor centre which opened at the end of last year, was a building that would blend unobtrusively into the wide-open Wiltshire landscape by evoking a copse of trees.
To achieve this effect, the two main enclosed spaces that make up the building are covered by a light, gently curving roof, supported by a forest of slender angled columns.
The interior spaces offer visitors two starkly contrasting experiences, one an atmospheric exhibition space clad in timber planking and the other a bright and airy café, shop and educational area encased in stunning Pilkington Optiwhite™
extra-clear, low-iron glass.
Terry Lidster, sales engineer at Pilkington Architectural, says: “The idea behind the glass pavilion was to connect the interior of the building with the striking landscape that surrounds it on all sides.
"The architect wanted the interior to be both visible from outside to entice people in while, more importantly, allowing those inside a view out that was as bright and naturally coloured as possible. For this reason, the glass selection was paramount, and maximum transparency was key.”
Elegant yet robust
The project presented a structural challenge for the glazing system, as architects Denton Corker Marshall were keen to increase the feeling of space inside the building by maximising the height of the glazing. At 4.3 metres tall, the glass needed to be thick and strong enough to stand up to the force of the high wind acting on it, and also meet building regulations for low-level glazing. Adding to this challenge was an aesthetic requirement to avoid any exterior bolts on the glass.
To meet this brief, the Pilkington Planar™
Intrafix structural glazing system was specified, with high-level perpendicular glass fins positioned at the join of each pane in order to secure it to the edge of the roof while keeping the fixings as hidden as possible and the floor area free for displays.
Anthony Williams, contracts manager at Vitrine Systems explains: “The glazing we provided gives the appearance of an almost free-standing, delicate wall of glass, while in fact the system has a great deal of structural strength and is, of course, solidly fixed to the building.
"The way the fixings are hidden helps maintain the clean lines of the pavilion, with the top and bottom of the glass sitting in channel rebates within the floor and ceiling, while the fins provide additional lateral strength and help to anchor the system to the roof structure.”
With all four sides of the pavilion consisting of high glass walls, the ability of the glass to retain heat was another priority for the designers.
To address this, Pilkington K Glass™
OW was used for the outer pane of the double glazing system, which comprises a low-emissivity coating on the inner face of the outside pane of glass, reflecting heat back into the building.
Terry Lidster adds: “The wide range of Pilkington products we manufacture enable us to create bespoke combinations project by project.
“For the Stonehenge scheme, the use of Pilkington K Glass™
OW as the outer pane and toughened Pilkington Optiwhite™
as the inner pane, delivers the best of both worlds in terms of allowing the maximum amount of energy and light from the sun to enter the building and help to heat the space, while at the same time minimising the amount of heat loss. The 16mm argon-filled cavity between the panes ensures conduction of heat through the glass is also kept to a minimum. The result is that the sweeping views and light filled pavilion enjoyed by those inside the centre do not come at the expense of energ-efficiency.”