Stirling Prize shortlist 2023: Courtauld Institute of Art by Witherford Watson Mann

I have long been bemused by the Courtauld Institute of Art, which seemed to dissuade visitors to its remarkable art collection with an off-putting dark entrance in the otherwise welcoming Somerset House on London’s Strand. Now Witherford Watson Mann Architects’ £26.5 million Stirling Prize shortlisted project has carved open and made sense of the blocks for the university, gallery and conservation work of this institution – all this in just the first phase of ongoing works. 

The palatial neo-classical block with deep incised rustication obscures the fact that Sir William Chambers arranged this like a terrace to house nine organisations in the 1770s, each with their own separate territories. With some focused interventions WWM has eased the routes through, creating a gentle circulation route for visitors and works of art, turning fussy galleries into simpler, lighter spaces in the grade 1 listed building. 

Witherford Watson Mann won the project through an open OJEU competition, fresh from its 2013 Stirling Prize win for Astley Castle, which had been a precision process of demolition, rebuilding and retention. With similar strategies Courtauld Connects readies the institution for the return of decanted art students to the site with its biggest move, opening up the vaults. This included excavation to create level floors with sufficient head height, cutting through the brick vaults. The sleek new concrete structure matches the brick vaults in solid grandeur and will ultimately link the gallery to the student areas, perhaps with a café that opens onto the sunken two-storey lightwells that bring a filtered light to this level – although for now it is an oversized gallery shop.

But for gallery visitors the most significant changes are to the entrance sequence and circulation. The steps up from Strand and the porte cochère have been seamlessly smoothed into a ramp, with the Swedish limestone re-used and the ramp edges given a depth with solid matching stone from the original quarry. It is the first of WWM’s barely-there alterations that make the world of difference. 

But a more dramatic move was needed inside at ground level, where a gallery was removed to expand the entry space and a new, cantilevered York stone staircase inserted which descends to the lower ground floor of lockers and shop, giving extra capacity that the narrow 1770s staircase can’t carry. Like all the moves in this building, there were trade-offs, new interventions off set by restorative moves elsewhere – in this case the storage room above becoming the Medieval Gallery. 

As you ascend the main staircase (its railings returned to a vibrant, if unexpected, Prussian blue) you see into the galleries of the first floor. As with WWM’s work at the Whitechapel Gallery, the galleries look just as they should be, but have been taken apart with partitions removed, fine gallery track lighting installed and wall panels subtly detailed to allow direct hanging despite the listed walls. The wooden floors had special attention from both the practice and some of the 36 trades that worked on site, not just the pennies as spacers between boards but also the way the widest boards are positioned at centre of the historic galleries, narrowing at the edges, as was often done in the 18th century. The galleries on the top floor have been transformed into a connected suite around the Great Room, once again a single volume bathed in natural light, echoed in the two new galleries for temporary exhibitions. 

The intimate Prints and Drawings gallery, completed by WWM before the main project was in the offing, set the template for collaboration with the curating team, creating spaces in which they could take risks with less formal hangs. The concentrated focus on the questions of how windows and doors could add to the gallery experience came out in the rest of the project, where daylight control and views are handled with removable panels, white blinds for serious light control and perfectly judged transparent black blinds just to take light levels down but maintain a relationship between inside and out. Chambers’ chamfered corner doorways were reworked with cabinetry creating entry portals – artist Peter Doig was apparently very taken with WWM’s own corner doorway between Temporary Exhibition galleries when he hung his show. One of WWM’s almost-invisible changes was negotiating the removal of the pairs of double doors between each historic gallery that had interrupted the flow down, creating awkward eddies in visitors confronted by a projecting door; now each upgraded single pair of doors is held open in the reveals between rooms.

This is a hugely technical project, but you wouldn’t know it from the bold structural moves and a grace and elegance that is concerned to give the weight and substance to detail that William Chambers’ design demands. It has gained the Courtauld an extra 50m2, but more importantly it has made what is there a pleasure to curate and a delight to be in and move around. The visitor numbers are some testament to that, going from an average of 206,000 a year to 320,000 in its first 12 months since reopening.

Barrels and fans – dealing with the vaults
A view from David Derby, Price and Myers

From competition stage WWM planned to connect through the three underground vaults below the entrance arches to Somerset House. This required turning the barrel vaults into fan vaults, removing the central one as it was so low. 

Structurally this meant supporting the vaults themselves, the live access road and the floors of galleries during the work. We had 40 detailed drawings of the temporary works and sequencing. We cut through the brick vaults and held them in place with steel angles. With side aisles as support walls, we had to prop it through two levels of basements. A supporting bridge for emergency access into Somerset House kept vehicles’ wheels within channels to ensure they didn’t scrape the stonework arches just above. 

You don’t realise the complexity of what you are doing until you draw it out in detail. This we did twice, once for a steel structure and then in concrete as the contractor advised there wasn’t enough space to get steel in. 

One day just before the first Covid lockdown, the self-compacting concrete was pumped in a single pour. Then we just had to release it all down again. 

David Derby, Price and Myers

Sustainability data

Predicted on-site renewable energy generation (kWh/yr) 0 
Predicted potable water use (Litre per person per day) 10.68
Actual annual gas usage (kWh/m²/yr) 137
Actual annual electricity usage (kWh/m²/yr) 86 
Upfront carbon (KgCO₂eq/m²)  106 
RICS modules A1-A5, structure only

In numbers

Gross internal area 5310m²
Project construction cost £26.5m
Cost per m²  £4,990

Watch short films of all the 2023 shortlisted projects

Hear the stories behind the buildings from the architects live at Stirling Shortlist talk on 5 October and the winners talk on 9 November. 
And coming soon, see inside the buildings in the Stirling Stories online CPD package on RIBA Academy