Watch our webinar in collaboration with Schüco, which explores the future of sustainable, multitasking facades.

Speaking at the AT Schüco webinar on sustainable facades, Mark Tynan of Make Architects illustrated his talk with a diagram of carbon savings. It shows the most effective ways of saving operational carbon and embodied carbon in buildings. In terms of operational carbon, the most effective factor is the geometry of the building, and next come the facades. With embodied carbon, the layout is most important, including retrofit and re-use options, and next come material choices. Facades are mentioned once, but they impact on all these other features as well. We all know that ‘fabric first’ is the best approach to achieving sustainable buildings, and facades form a significant proportion of the fabric. So looking at sustainable facades is vital if we are to have better buildings.

Speakers from left to right: Carol Patterson, Sandy Wright, and Mark Tynan

During this webinar, three architects talked about three very different projects and their facades. Tynan’s 80 Charlotte Street scheme in Fitzrovia, London, was of interest particularly because of its mix of retained and new elements. The project comprises mainly office and residential space, with some retail as well. There is also a new pocket park.

Where possible, Make has retained facades and re-used them, principally on the residential buildings. The architect also planned in some areas to re-use a 1960s structure and re-clad it. But a condition survey showed that it was defective, with poor rebar cover and honeycombing. Repairs would have been extensive, complicated and time consuming, so the decision was taken to demolish. However, some of the demolition materials have been recycled for use as aggregates in the building’s new concrete.

80 Charlotte Street in London, designed by Make Architects (ph: Make Architects)

One of the important aspects of the facade is that the window to wall ratio is only about 40 per cent, reducing the potential for solar gain. And there is another benefit, said Tynan. Making the bottom part of each wall opaque conceals untidy elements. ‘You often see a lot of clutter against full-height glazing,’ he said. ‘Making the facade solid up to about 75mm tidies up the appearance.’

Courtyard view of 80 Charlotte Street (ph: Make Architects)

The cladding is in precast concrete and brick. Using solid materials like these, Tynan said, will extend the durability way beyond a nominal 20-year design life. Another important aspect is flexibility – the facades have been designed to be self-supporting which means that everything behind them can be altered if requirements change.

Although the group of buildings that make up the project seem relatively straightforward, there is actually a lot of complexity in the design. Facades are different to reflect various aspects, and there had to be some careful adjustments between mismatched levels of new and existing elements.

St John’s College Library, Oxford, by Wright & Wright Architects (ph: Hufton & Crow)

There was a similar need to integrate with existing buildings when Wright & Wright Architects designed a new library for St John’s College, Oxford. The building had to sit between a listed wall and the president’s garden. One condition was that the scheme should not overlook the garden.

As well as providing much-needed additional reading spaces, an aim of the new building was to reconnect parts of the college that had come to feel a little remote. Sandy Wright of Wright and Wright explained that they uncovered an old store in a cloister that was the site of the previous ‘Otranto passage’. The architect used this to place for a new staircase, and to solve fire and access problems between the new and old buildings.

Interior view of St John’s College Library (ph: Hufton & Crow)

The main problem was how to bring light into the new library, given the site restrictions. The architect designed a stepped staggered wall to the president’s garden. The elements running parallel to the boundary were opaque but the ‘steps’ were infilled with glass, so that there was light coming in but no views out.

Artist Susanna Heron took part of this wall and made it into a gigantic stone sculpture called ‘Stone Drawing’ which uses a low relief of abstract forms both inside and out. To separate the library from the garden, the architect designed a moat. ‘There is a play of light though the glass from the slightly agitated water, inspired by the Alhambra,’ said Wright.

The book stacks are in the centre of the library, allowing readers to enjoy light both beside the staggered wall and in reading positions above the listed wall.

OMA’s Brighton College in East Sussex (ph: Laurian Ghinitoiu, OMA)

The third building is a sports and science centre for Brighton College, designed by OMA. The architect came up with a design that emphasises the cellular nature of the science buildings spanning over the larger sports spaces. ‘This,’ explained Carol Patterson of OMA, ‘makes reference to the strong party walls of nearby buildings and also to beach structures’.

Brighton College is partly clad with glass-fibre reinforced concrete (ph: Laurian Ghinitoiu, OMA)

Cladding is with a GFRC (glass-fibre reinforced concrete) product called FibreC in a dark anthracite colour. The design maximises views over the sports field, but on the other side uses largely channel glass with Okalux insulation to prevent overlooking of residential areas. Each laboratory, however, has a window through which students can look out.

Stepped roof terraces at Brighton College (ph: Laurian Ghinitoiu, OMA)

The architect has thought hard about the ventilation in the building and the use of roof space. This is an unusual scheme, not least because it combines two facilities into a single structure when the original brief was for two separate buildings. It has an original approach to facades, as do the other two projects discussed. There are as many ways to design sustainable facades as there are architects and building designs.