Inspiration

Pinnacle House, Royal Wharf

The scalloped facade and sparkling Dolomite sand of Mæ Architects’ apartment block are awash with Thames history, writes Nick Jones

The area of London’s docks that used to be known as Minoco Wharf has sharpened up its image in recent years. Once an industrial works, where high explosives were manufactured in the First World War, it is being turned into Royal Wharf, a “riverside neighbourhood” of 3,385 homes, shops and restaurants, masterplanned by Glenn Howells Architects. But with dramatic change comes a desire to connect to the past – and for Royal Wharf’s latest apartment building, that connection is expressed via its precast-concrete facade.

Pinnacle House, designed by Mæ Architects, is the development’s tallest building at 14 storeys (the flightpath to City Airport precludes anything higher) and sits at the head of a park that stretches down to the Thames. It comprises a reinforced-concrete tower and a shorter shoulder block to the north, and contains 110 one-, two- and three-bedroom flats, as well as cafes and restaurants at ground level. In the interests of material efficiency, the two parts of the building share a core.

The exterior is wrapped in a grid-like frame that stands up to 2m proud of the building’s rainscreen, making a deep two-layer facade with continuous balconies for flats on the east, south and west sides of the tower. This device has as much in common with a Renaissance loggia as a 21st-century London tower – Mæ founder Alex Ely says that the basilica of San Michele in Foro in Tuscany was a reference point. “There’s something rather lovely about the depth and shadow you get on a facade like that.”

The facade design also had a more local reference point. Each bay is topped by a scalloped beam, adding to the play of light, but also providing a nod to the site’s history – specifically the oyster shells unearthed during the excavation of the dock walls. In another classical allusion, the tower has a tripartite structure, with the columns becoming slimmer and the scallops wider as the tower rises.

The three distinct sections are marked by a cornice on the third, sixth and ninth levels. “It is open towards the sky, with a bit more privacy towards the ground,” says Ely. “It’s quite understated but once you draw attention to it, you can’t stop spotting it.” This subtle variation meant that the precaster needed several bespoke timber moulds per section, covering the changing profiles of the columns and flat and radial beams.

The concrete for the facade is a combination of limestone aggregates and Spanish Dolomite sands, with white cement. Mæ initially explored the idea of adding oyster shells – in the manner of the “tabby concrete” used by early settlers to North America. However, this was deemed out of keeping with the development’s other largely precast and brick-clad facades, and it was left to the sands to give a pearllike iridescence. “You definitely see that little glint in the way you do with oyster shells,” says Ely. Again, the mix and the finish change subtly as the tower rises: the lower section is deeply shot-blasted and acid-etched, while the upper levels are smoother and whiter, thanks to a higher proportion of sands.

The gentle implication of sedimentary action is another gesture towards the bankside setting. The ability to control the detailing to this degree was a big reason for using precast concrete, Ely adds. The facades are structural, supporting the reinforced-concrete balconies behind. The balconies were cast in situ with the rest of the concrete frame (with a thermal break at the building perimeter). A system of temporary props was erected to support the projecting balconies until the precast panels, which were cast in one-storey-high, 5m-wide sections, could be retrospectively installed.

The resulting balconies are certainly luxurious for an apartment building, but they also perform an essential function: “We were interested in how facades can control climate, so we see this as part of the ecological ambition for the building. By providing deep shading on the south facade overlooking the river, and also the east and west sides, it is managing the internal climate.” Ely hopes that the ecological ambition will extend to greenery spilling out over the balconies, but the design leaves this in residents’ hands. He contrasts this organic approach to The Barbican, where he lives, and where each flat’s fixed concrete planters invite a more inflexible response. “The balconies [at Pinnacle House] are just enormous, so you could have a garden on there. It’s a very formal piece of architecture, but if someone strung a hammock up, put a shed out or planted it up, I’d love that.”

PROJECT TEAM

Architect Mæ Architects
Executive architect Whittam Cox Architects
Structural engineer OCSC
In-situ concrete Henry Construction
Precast concrete Evans Concrete

Photos: Rory Gardiner