Tight corners, red tape and amazing grace – why architects love a tricky site

There’s a concrete building on the right, as you head into London Euston station by train, that’s brooding, impressive in an almost-Roman way, and a bit mysterious. Its upper levels jetty towards the tracks, as if they were the outside of a stadium, but it’s also as long and insistent as a viaduct. This is, it turns out, the back of the Alexandra Road estate , the celebrated 1970s housing project by Neave Brown and the London Borough of Camden. The big, sheltering rear wall allows a peaceful and sociable gently curving street, overlooked by stepped-back terraces of homes, to be created within the development.

This structure grows out of the difficulties of building next to a mainline railway – the need to screen noise; the constructional demands of inserting foundations next to working tracks – and transforms them into something mighty and memorable. It may not have been strictly necessary to deal with such issues with so much spectacle. Something more calm and sensible might have been possible. But then architects do like to make drama out of a constraint.

Alexandra Road is one of the projects on show in Difficult Sites: Architecture Against the Odds , an exhibition at the Royal Institute of British Architects. Its theme is the ways in which the design of buildings can overcome, indeed be inspired by, such things as underground train tunnels, steep terrain, narrow sites and the presence of existing buildings. There’s a rusty water tower in Norfolk converted into a home by Mike Tonkin and Anna Liu, and a house by the upper Thames by Knox Bhavan, raised above the level of future floods. There’s Charles Holden’s 1929 headquarters for the Underground Electric Railways Company of London – a Portland stone ziggurat whose emphatic mass gives little clue that a hidden steel frame carries it over the tracks and platforms of St James’s Park tube station.

You could call Holden’s building “art deco”, according to the loose usage of the term that currently prevails. It is part of the exhibition’s studiously broad church of architectural styles, spread over a time span of a century and a bit. Other examples include Creek Vean , the modernist 1966 house designed by Su and Richard Rogers and Norman and Wendy Foster on a slope in Cornwall, but also a modern-gothic stair-and-lift tower of 2018 , inserted by the neo-traditionalist architect Ptolemy Dean amid the flying buttresses of Westminster Abbey and its chapter house.

With the Eden Project, a thing of mathematics encounters a thing of chaos to make a work more interesting than either

The Arts and Crafts movement is represented by Stoneywell , an 1899 house in Leicestershire. Here the challenge is self-imposed, as its architect, Ernest Gimson, chose to make its walls out of rough stones found on or near its site, creating a hunched, rugged building that seems to grow out its place. An opposite response to landscape, but equally respectful, is taken by a 2019 house in Nedd, in the Scottish Highlands, designed by the Perthshire-based Mary Arnold-Forster. Here the building sits lightly on the rocky land , made out of timber elements prefabricated elsewhere and transported to the site, their dimensions determined by the size of lorry that could travel the single-track road to the site.

With other projects the difficulties are political and cultural. The exhibition shows the extension to the National Gallery, by Ahrends Burton and Koralek , that the monarch formerly known as Prince Charles called “a monstrous carbuncle”, as well as the Sainsbury Wing, by Venturi, Scott Brown, that was then built instead . The ABK scheme now looks dignified and assured, such that you wonder what all the fuss was about, and gives credence to the never-proved rumour that the prince confused it with a more boisterous competition entry by Richard Rogers.

This small but rewarding show is a celebration of architectural skill and ingenuity, spurred on by whatever complexities might arise. Its exhibits include models and drawings supplied by contemporary practices, and taken (albeit, regrettably, only as reproductions) from RIBA’s collections. They run from a composed presentation drawing by Basil Spence for Coventry Cathedral (where the task was to combine the new building with the bombed-out ruin of its medieval predecessor) to a smudgy little sketch of a cross-section of the British Library, in which the destiny of much digging and many tonnes of concrete was described by a few strokes of soft pencil.

There’s pleasure to be taken in the craft of these drawings, in their hatching and shadows and atmospherics, in the romantically stormy sky that gathers over Holden’s headquarters for a transport organisation, or the reflected light that bounces around the portico of Spence’s cathedral. There’s a closeness between the making of a drawing and of a building, a confidence in the artistry of an architect. There’s a deftness, in the case of the British Library sketch, that belies the fact that this building emerged from a decades-long tangle of political indecision, bureaucratic complexity and physical constraints – with, as it turned out, an amazing level of grace.

So the exhibition is about grit in oysters and the paddling of swan’s feet beneath the surface. The British Library is shown to be an iceberg – above ground are the public parts of the building, sloping back (as planners required) to preserve views of St Pancras station and its neo-gothic hotel. Below ground are vast amounts of book storage that have to dodge the tunnels of the Victoria and Northern Lines. Some projects seek to soar above the mucky stuff. Others embrace the difficulties, making them into an occasion to create something that would never otherwise have come into being.

An outstanding example of the latter is the Eden Project in Cornwall, designed by Grimshaw, where the task was to create “biomes” – microcosms of different types of climate – on cliffs and hollows left by a former china clay quarry. The result is an array of intersecting geodesic bubbles, with a lightweight roof of translucent inflatable cushions, draped irregularly over the ragged land. A thing of mathematics encounters a thing of chaos to make a work more interesting than either, which as well as being a successful visitor attraction, is one of the most remarkable buildings of the lottery-funded boom in cultural and science projects at the turn of the millennium.

The ways in which buildings are procured these days, especially with larger projects, with multiple layers of consultants and contractors, make for a less close connection between the architect’s sketching hand and the finished object than can be seen in some of the older exhibits. Such directness is more possible at a smaller scale, which is probably why many of the projects in the show are private houses. But the qualities of thought on display are as relevant as ever, as the physical demands of climate emergency, and the challenges of providing new housing on a restricted supply of land, bring a whole new level of difficulty to bear. In these circumstances, design is not a luxury but a necessity. It’s beyond the scope of the RIBA exhibition to propose how these vaster challenges can be met, but it demonstrates creative intelligence that can be applied to more than the occasional delightful home.

• Difficult Sites: Architecture Against the Odds is at RIBA, 66 Portland Place, London, until spring 2025