National Automotive Innovation Centre, Coventry

Introduction

As the future becomes low carbon, car manufacturers are adapting to the consequences with research and innovation into new concepts of transport. So the recent opening of the National Automotive Innovation Centre (NAIC) was well-timed; it is a new centre for automotive design, bringing together academic teams, engineers and designers to combine expertise from universities, industry, supply companies and small businesses. The centre is the largest of its kind in Europe and the result of a unique partnership between the British car industry – Jaguar Land Rover and Tata Motors – and academia – Warwick Manufacturing Group (WMG), the university’s research arm. The architect, Cullinan Studio, has worked with WMG for many years and the NAIC is the largest of a group of buildings on the WMG campus at the University of Warwick.

The brief for this hybrid of industrial building, university faculty and automotive research centre required a design that reflected the innovative purpose of the activities taking place inside, while providing a complex assembly of spaces for up to 1000 staff. These include an engineering hall, design studios and research laboratories, student lecture rooms, open plan offices and meeting rooms, together with spaces big enough for car launch events.

To unify the many different activities, the architect has housed them in a single four-storey enclosure with timber walls and an oversailing diagrid roof, one of the largest timber roofs in the world. The roof is clearly visible at first sight of the building, extending beyond the main entrance to create a sheltering canopy four-storeys high. It continues inside above the entrance atrium and beyond, where a set of concrete internal terraces, curved and set back from the others as they rise, forms a ‘collaborative hub’ where common technologies are shared. A variety of large and small workplace settings, from individual booths to large spaces for weekly specialist team meetings, are gathered round this collaborative hub. As practice leader and director of Cullinan Studio, architect Roddy Langmuir explains: ‘The sets of balconies rising to the showroom at the top both underline the openness of the spaces but create a theatrical route up: a promenade through a hillside town. You can see all the activities going on. It’s a four-storey building, but almost everybody chooses to use the stairs.’

The internal four-storey terraces are of exposed cast-insitu concrete. The external envelope is a pioneering system of prefabricated timber megapanels which support a delicately waved façade of expanded aluminium mesh.

The timber roof structure

Timber might not be seen as the obvious choice for the roof of an automotive research centre. But from earliest design sketches it became clear that the qualities of an oversailing timber diagrid roof were exactly what were needed to fulfil the brief. As an exposed repetitive element soaring over the whole building, it is unique in its ability to unify the many activities housed beneath it, acting as a symbol of technical collaboration, and also suggesting the industry transition to a low carbon future. Its innovative, robustly engineered structure reflects the very similar aims and ideals of the client. In addition, the tone and texture of such a warm natural material enhances its industrial setting and there is evidence for its contribution to wellbeing.

The structural engineer Arup originally conceived the timber roof as a true lamella, short lengths of glulam interconnected and mutually supported to span onto supporting RHS beams on a 15 metre grid. Various forms of lamella mesh were investigated at concept stage to optimise the depth and volume of the glulam, but the final design adopted was a one-way diagrid of glulam joists which replicated the lamella form but had the advantage that it substantially sped up construction and reduced costs by avoiding the extensive temporary supports required for a true lamella roof.

The geometric form is maintained by means of a simple hierarchy of primary and secondary glulam beams which intersect across the 15 x 15 metre module to create a diagonal subgrid of coffers approximately 2.5 x 2.5 metres in size. The diagrid was slightly pitched to create a nominal fall for the roof and tapered within each bay, with depth increasing where bending moments were greatest. Individual connections between glulam members were investigated by the specialist structural engineer and sub-contractor B&K Structures and a screwed shear connection was chosen which was easy to install and allowed for some variability of fabrication and site tolerances. The connections were fixed from the top so as to be visually unobtrusive.

The glulam diagrids are supported by RHS beams set between them at 15 metre centres and, where a larger column-free span was required, Arup devised a steel bowstring truss which extended the column-free area to 30 metres. The RHS frame is supported on circular steel columns.

Internally, the depth of the glulam lattice grids are masked by a series of acoustic ceiling panels recessed within the upper parts. The panels are of perforated plywood with integrated lighting and smoke detectors.

The glulam diagrid is overlaid with a highly insulated CLT deck, with large 7.5 x 7.5 metre rooflight structures built up in CLT to support the ETFE rooflights. The rooflights give daylight to internal collaborative hub spaces set deep within the plan and to the atrium.

The timber megapanels and external cladding

The external walls were constructed with a pioneering system of prefabricated, insulated timber and CLT megapanels. The system was developed by Cullinan Studio and Arup Façades as a low carbon, pre-assembled alternative to steel cassettes. By using timber, the problem of cold bridges is avoided and a greatly improved thermal performance can be achieved. The system is self supporting and requires no secondary steelwork. The megapanels can also be prefabricated in very large sizes which are ideal for large buildings, fast to erect, efficient and flexible.

The NAIC megapanels are 358mm thick with an outer leaf of 80mm CLT enclosing a timber frame filled with Rockwool insulation and an inner leaf of oriented strand board (OSB). The outer CLT face is covered with a fire-rated and waterproof rainscreen membrane which was lapped and jointed after installation. The inner OSB face is lined with a vapour control layer.

The facades of the NAIC include horizontal bands of glazing on upper floors and the megapanels were fabricated to run between the glazed openings, with the size of a typical megapanel in the region of 10 metres high and 1.4 metres wide. They were bolted with steel brackets to the cast in-situ concrete floor slabs at each level.

The megapanels were prefabricated in Austria by Rubner Holzbau and installed by B&K Structures.

A delicate rainscreen of curved silver aluminium mesh panels is fixed to the megapanels with projecting aluminium stub posts. The curved panels are fixed alternately in convex and concave forms to create a sinusoidal wave profile running along the facade. In fixing the aluminium posts, another major advantage of the megapanels was revealed; the CLT outer leaf allowed greatly improved fixing tolerances compared to steel cassettes.

In some areas the aluminium mesh extends over the glazing to act as sun shading, reducing solar gain; sunlight tracks across the rippling mesh during the day to create a feeling of movement along the façade – another reference to automotive design.

Sustainability

The NAIC has achieved BREEAM ‘Excellent’ and an EPC of A. The glulam and CLT roof creates a significant sequestration of 612 tonnes of carbon. This reduces the overall embedded carbon of the superstructure by 22 per cent from approximately 160 kgCO2/m2 to 125 kgCO2/m2.

All the timber has PEFC or FSC chain of custody certification to demonstrate they have been sourced from sustainable sources. FSC timber and other sustainability requirements are incorporated into the University’s Green Lease for the NAIC, so that the sustainable aspirations are carried forward for future adaptations.

To achieve the best combination of annual energy and carbon reduction, the building is linked to the University’s district heating scheme and the roof is fitted with photovoltaic panels.

Awards

Wood Awards 2020 Winner – Structural Award
RIBA Regional Award 2021
RIBA West Midlands Awards – Building of the Year 2021
RIBA West Midlands Awards – Client of the Year 2021
AJ Architecture Awards 2021 – Shortlist
BCO Regional and National Award for Innovation 2021
Civic Trust Awards 2021 – Regional Finalist
Building Awards 2020 – Project of the Year
AIA UK Design Award for Sustainability 2020
FX Design Awards 2020 – Finalist
RIBA National Award 2021 – Winner
RIBA Client of the Year 2021 – Currently shortlisted

 

Prepared by the publishing team with contributor Susan Dawson.

Completion date:

August 2019

Building type:

Research and development centre

Location:

University of Warwick, Coventry

Architect:

Cullinan Studio

Structural engineer:

Arup

Structural engineer (timber roof detailed design):

Engenuiti

Main contractor:

Balfour Beatty

Timber structure subcontractor and installer:

B&K Structures

Timber supplier:

Rubner Holzbau, Binderholz

Timber elements:

Roof structure, structural wall panels

Timber species:

PEFC and FSC-certified spruce

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