Heelis – National Trust HQ.

The industrial saw-tooth roof form and careful orientation of National Trust’s Swindon headquarters bring two of the organisation’s aspirations to the fore: a wish to demonstrate long-term sustainability and another to maintain the character of a historically significant environment.

Location

Swindon, UK

Client

National Trust

Architect

Feilden Clegg Bradley Studios

Project Value

£12 million

Floor Area

7,100 m²

Status

completed 2005

Expertise

Structures

Though architect FCB’s design incorporates a deep floor plan, the sensitive angling of the building footprint and introduction of roof-lights brings daylight to this two-storey building, consolidating 430 staff previously scattered across four different offices. Solar panels, in locations that maximise their exposure to sunlight, generate a large proportion of the building’s electricity. Ventilation ‘snouts’, designed to provide wind-driven ventilation whatever the weather, also offer lateral shading to adjacent roof-lights whilst maintaining a view of the sky.

Ground conditions were variable below the initial layer of tarmac, with made ground extending to anywhere between 1.2 m and 3.4 m deep, and included a number of noted obstructions. We specified piled foundations to cut through to a layer of Kimmeridge Clay, and a suspended slab to allow for ground movement and provide separation between the building and potential contamination below.

The brownfield site was once home to Brunel’s Great Western Railway complex, and still houses a number of brick-clad shed structures with corrugated roofs. A similar design was chosen here, with blue engineering bricks utilised on the majority of elevations. Timber was considered for the roof construction due to its short-term sustainability credentials, but in keeping with the industrial ethos a steel frame portal was chosen. Steel has a high embodied energy, but achieves economy since it requires a lower volume of material to span the necessary structural widths, and can be assembled quickly and efficiently. To increase the building’s thermal mass, concrete floors and roof cladding panels were chosen, with the soffits left exposed.