The roof of the Vaults Pavilion is an exuberant landmark on Tower Hill Square. It identifies the entrance to the original Vaults building, houses the new ticket kiosks and captures the existing raised terrace to its rear.
The pavilion is one of three, conceived as a linked colonnade from the top of the hill to the river. They share a common language of stone walls that 'fold-up' from the landscape and visually lightweight roofs.
The Vaults Pavilion roof is 45m x 12m, set 6.5m at its highest end. Stability is achieved with vertically cantilevering columns in conjunction with a cross-braced roof, which avoids the need for vertical cross bracing. Pre-cambered beams address dead-load deflection.
Exposed 356 x 171 x 57mm UB sections are joined to create a perimeter frame along each edge of the roof, supported by 168 x 10mm CHS columns at one side.
Visible connections were designed using countersunk bolts to minimise the thickness of connection plates. A 'ladder frame' at mid roof-span uses 300 x 100 x 16mm RHS columns, clad with aluminium.
The roof structure supports a warm deck build-up, with tapered rigid insulation and a single-ply membrane over profiled metal decking. This provides a base for secondary framing supporting panels of anodised aluminium grilles.
These give an uninterrupted 'fifth' elevation, visible from Tower Hill and beyond.