The Switch House, Herzog & De Meuron’s new ‘wing’ to the Tate Modern in London, recently opened.

The firm was responsible 22 years ago for the conversion of the Bankside Power Station into the Tate Modern, a project receiving about 5 million visitors annually – apparently twice as much as initially expected, according to information n the building on the website Archdaily and made available by the architects.

Just as the elements in the ‘original’ Tate Modern still are known by their ‘power station’ names (Turbine Hall, Boiler House etc.), the Switch House is built on the terrain of the power station’s original switch house. It stands on a terrace in the shape of three interlocking circles – indicating where the oil tanks used to be. The building is a pyramid of bricks, or, according to Edwin Heathcote in the Financial Times: “The tower is tall yet squat and curiously formed, gently folded, slotted and tapering. The fold and the sharp edge make it appear slimmer and taller, emphasising its height. It is the brick tower that is the motif for the project but it’s only one component. ”

The building’s only 336 000 bricks reinterpret the original power station’s brickwork in a radical way. “This unique façade allows light to filter in during the day and to glow out in the evening, transforming a solid, massive material into a veil that covers the concrete skeleton of the new building.”

The first four floors – all gallery space – also have vertical windows reminding one of those in the original Boiler House and visitors can see the landscape or the adjacent Turbine Hall from here. This is followed by administrative space and, right at the top, is a lookout-point with 360-degree views of London.

The new building forms a unit with the original Tate Modern. Heathcote states: “The new phase completes the work that the architects started to work on in 1994. Twenty-two years is a long time in contemporary architecture and fashions change fast, yet this now feels like an institution that has evolved. Herzog & De Meuron refer to it as an “organism”, in which the parts are clearly different yet have a common genetic code. From an urban point of view what they have achieved here is quite remarkable. They have managed to integrate the former power station into the city and streets behind while maintaining its sense of presence and difference.”