One of the most fascinating figures of 20th-century architecture, Walter Segal was born in Berlin but spent a formative part of his childhood in Ascona, Switzerland. His father was an artist, and he grew up among the creatives and intellectuals who gathered on the banks of Lake Maggiore, a refuge from the First World War.

Segal trained in Berlin, a city that was at the forefront of Modernism, and moved to London in 1936. It wasn’t until the 1960s, however, that he began to gain recognition for his ideas and methods. Today, his reputation continues to rise – not least because of his environmentally friendly approach to building.

In 1963 Segal married his second wife, Moran Scott. With six children between them, they decided to demolish Scott's Victorian house on North Hill in Highgate and replace it with a modern dwelling for the family to live in. The house is typical of his work in many ways, with its simple plan, minimal detailing and respect for the surrounding landscape. It also shows the architect’s uncanny ability to create an atmosphere that is both cosseting and wonderfully uplifting.

Simplicity of construction was important: only six trades were used, and wet trades were kept to a minimum. The house is a masonry cross-wall structure with light longitudinal elevations in glass and brick. The floors and roof are joisted timber. Rolled-steel sections form lintels, to avoid the use of concrete. The flat roof, with its prominent overhangs, is a recurrent theme of Segal’s buildings.

So as to maximise the useable space, optimum circulation was arithmetically determined at 12%. Originally there were six small bedrooms, but it was intended to be adaptable. Segal worked from home, and his studio on the ground floor was designed with separate access from the entrance courtyard. The internal materials are all fair-faced, and there is an almost total avoidance of architraves and trims. Pale sand-lime brickwork is sanded internally to give a smoother finish, and non-structural partitions are finished with vertical pine boarding.

In her book ‘Architects’ London Houses’ (1992), Miranda Newton wrote:

“Segal’s house shows his particular interest in timber detailing. No traditional methods, such as dowels, mortices or tenons, are used, only straight glued or bolted joints. This individualistic approach is immediately noticeable. The window detail, two sheets of plate glass supported in parallel L-angles bolted through to the linings, is simple and successful… Internally, the standard of joinery is noticeably superior.

“The stair is a strong, characteristic image for the house… Vertical timbers hang from the upper level with bolted treads. Despite the open risers, a sense of security is created by the forest of slender vertical timbers which enclose the stair. Segal preferred an uncluttered environment. His joy was in the materials and the quality of the detailing, particularly in the carpentry…

“Segal was a rare combination of central European intellectual and scholar and thoroughly practical technical innovator. The house reflects the character of its architect, and is private and individualistic. It has scope for leisure and living.”

Segal lived and worked at the house until his death in 1985. It was to be the last that he designed in bricks and mortar. While it was being built, he needed a temporary home for his family to live in, so he created a wooden cabin at the bottom of the garden. It cost £800 and took two weeks to build. Known as the Little House, this influential structure lasted over 50 years, before finally falling into disrepair. Segal was surprised by how much attention it attracted (Richard Rogers is one of many luminaries who made the pilgrimage to see it).

The design – a wooden frame, insulation and weatherproof shell – was the prototype for what became known as the Segal self-build method, which he pursued for the rest of his career. This was a way of building that eliminated the wet trades such as a brick-laying and cement-pouring, in favour of a modular timber system that is reminiscent of traditional Japanese architecture.

Segal was much influenced by the egalitarian principles of William Morris, as well as the early Modernists. “The buildings of the International Style”, he wrote, “were by definition unassuming… They were meant to promote wellbeing.” In an essay about the architect, Colin Ward wrote, “In his life, as well as his work, he tried to pare away the superfluous and concentrate on the important.”

In May 1988, the Architects’ Journal dedicated an entire issue to Walter Segal’s legacy and oeuvre, timed to coincide with an exhibition of his work at the Royal Festival Hall. The introduction pays fitting homage to this remarkable architect:

“Walter Segal was once described as ‘an absolutely stunning combination of an intensely practical architect and an intellectual’. Active in research, teaching and practice, he lived through the rise, dominance and subsequent decline of the Modern Movement. He is best remembered today for his truly architectural solution to the needs of self-builders – but this was only one of his many contributions to architecture.”