Morris + Company receives planning for timber extension to Walter Segal’s Highgate home

Morris + Company has received planning approval for a sensitive upgrade of the Highgate Village home built and lived in by pioneering architect Walter Segal. The scheme, to revive the original architecture of the house, and provide a generous home for future generations, complements the defining characteristic of Segals’ prefabricated, modular, timber-framed vernacular, and adopts his principles of efficient, lightweight, sustainable construction. At the same time, it celebrates a sensitive new layer of contemporary architecture to the iconic home.

The house at 9 North Hill, designed and built by Segal in 1965, is a modest, low-lying three-bedroom, two-storey detached house, that faces onto a large 126ft sloping garden; which lies in direct contrast to the grander and more elaborate neighbouring homes along North Hill, ranging from Georgian to early Twentieth Century. The proposed interventions by Morris + Company include an inconspicuous front extension, joining the house with the street, and a dynamic timber zig-zagged rear extension, connecting it to the 4,000 sq.ft of retained private garden. The project is estimated to commence January 2021 and complete October 2021.

The proposed front extension involves converting the entrance passageway off North Hill into a con- cealed cloakroom, with a new, high-ceilinged, light-filled volume to celebrate the threshold between the new and existing architecture, and provide an uninterrupted view of the original brickwork and exposed Segal staircase. The proposed rear extension will provide new accommodation set over two floors; including a ground floor living room with a hearth, a reading room and study, and an upper floor master-suite with a dual aspect over the garden. The scheme also involves landscaping of the verdant and unspoiled grounds.

The composition of the rear extension is derived from thorough analysis of the logic and layout of the original garden and house. The sequence of volumes is stacked and slipped both vertically and horizontally, graduating away from the main house, in order to preserve the reading of Segal’s orig- inal architecture; whilst at the same time creating a new, and legible whole. The internal composition continues Segal’s original zig-zag route through the main house that reveals glimpses of each on- coming room as you walk through the interior.

The stepped geometry of the extension follows the natural slope of the garden, limiting the amount of soil that will need to be excavated during construction, and reducing unnecessary impact on the eight mature trees that sit adjacent. The staggered layout also preserves views out to the garden from the main house.

The scheme includes a timber veil of uniformly spaced timber battens that wrap around the building, visually and structurally linking with the timber palisades used by Segal to divide large windows. It also includes a textured, aggregated concrete ribbon with high recycled content that wraps the base of the building, to provide a plinth to the house, and a juncture between the timber structure and the earth. The scheme also features a timber staircase and timber internal finishes to offer a smooth, warm touch and a sense of security and comfort.

The design features a composition of varied windows, hidden behind or punctuating the building’s skin, and each defined by the activities within; offering privacy in the bathroom; forming a window seat in the library; and bringing the garden into the living room. These openings are also designed to help to bring in natural light and solar gain during the day, whilst at night, the battens are designed to soften the interior’s lighting, to omit a warm glow and create a lantern-like effect.

The proposal aims to be congruent with many of Segal’s pioneering construction principles; using readily available locally sourced materials to create a low maintenance, modular, lightweight timber- framed system, and eliminating the need for excessive foundations, and specialist wet trades such as bricklaying and plastering. This design method, similar to the lightweight construction method used in traditional Japanese architecture, also allows great flexibility in planning, and infinite adap- tations and variations in the future.

The use of minimal repeated elements in the design is a key concept for the construction of the extension; from the structural components and interior lining, to the modulation of the cladding and envelope. To accommodate restricted site access, the architects have developed a component- based construction system, whereby small elements can be brought in and assembled on site. This in turn promotes the use of a simple structural timber-frame system of posts and beams and avoids excessive use of concrete. The repeated cladding panels can be manufactured in advance and brought to site as units to further reduce on-site construction time.