Francesco Pierazzi Architects Gives a Kingston Victorian Terrace a Sawtooth Roof Borrowed from Local Industry

Rear extensions on London terraces are so common that they have become almost invisible as architecture: a glass box, a flat roof, a kitchen island, repeat. Francesco Pierazzi Architects takes the same brief in Kingston upon Thames and asks a better question. If the extension doesn't need to imitate the Victorian house, what local history should it draw on instead? The answer is a double-sawtooth roof that recalls Middle Mill, the former home of The Patent Cocoa Fibre Co. Ltd., a coconut-fibre works a few streets from the site.

The numbers are modest. Sawtooth House grows from 165 m² to 180 m², with the extension adding only 15 m² while 125 m² of the existing house is refurbished. The ambition is not. The clients, one of whom is a climate-change academic, asked for a home that is environmentally rigorous and also joyful, and that can cope with hotter summers and heavier rain. What interests us is how directly the roof serves both aims: it gives the house its character, and it is also its daylighting strategy. The project got there the hard way, too. Earlier Permitted Development applications failed, the Local Authority preferred something more traditional, and permission finally came on appeal.

An Industrial Profile in London Stock Brick

From the garden, the extension reads as a pair of brick volumes with stepped, sloping parapets. The roofline rises and drops like a factory shed scaled down to fit a domestic plot. The brick is Smeed Dean Weathered Yellow Stock, the London stock type that already defines the surrounding terraces. That choice anchors a profile that could otherwise look imported.

The detailing earns a close look. Varied bonds and textured faces give the walls depth, and slanted zinc capping sharpens the parapets against the neighbouring tiled roofs. Brick was partly a practical choice tied to the planning route, but the architects have made it the project's main tool for fitting in. The building behaves like a good neighbour without pretending to be Victorian.

Framing the Garden and the Sunken Patio

The garden facade frames a sunken patio set between the brick volumes. It is a small move with a large effect. The terrace becomes an outdoor room held by the building, not a strip of paving left over at the back. Corner sliding glazing from Cortizo dissolves the junction between kitchen and garden, and a raised planter softens the edge where brick meets stone.

The landscape was designed by the architects with the clients' own gardener, and it works quietly to manage water. A 7,500-litre underground rainwater tank irrigates the planting, which matters on a plot meant to handle wetter winters and drier summers. A large maple anchors the view from inside, and the architecture is arranged around it.

A Kitchen That Anchors the Plan

Inside, the living space flows straight into the family kitchen. The rooflights stop that openness from becoming one undifferentiated room. A large rooflight sits above the terrazzo-topped peninsula and marks it as the centre of the house, while the long dining table and the open shelving pick up the rhythm of the roof above.

Three colourful pendant lamps hang below the daylit opening. They signal early that this interior has a sense of humour. The outside is restrained brick; the inside is allowed to play.

Terrazzo, Oak and a Personal Palette

The multicoloured terrazzo worktop, credited to Paolo Spinelli, is the material centrepiece. It wraps into a splashback, set against oak cabinetry by Ashton Woodcraft. The pairing is warm without being nostalgic. Speckled stone against grained timber gives the kitchen a tactile richness that a lacquered finish would never match.

Small framed views add to this. A narrow window looks onto ivy, and another view, according to the architects, picks out a mature yucca beyond the kitchen. These are deliberate pauses that keep the interior tied to the planting outside, even at the sink.

Light from Two Directions

The faceted white ceiling is where the roof concept turns into an interior experience. Angled planes catch and spread light, and the Velux rooflights face opposite ways: one side takes eastern morning sun, the other western evening light. In a narrow terrace, where daylight usually reaches only the front and back walls, that orientation changes how the house feels over the course of a day.

The angled ceilings also mark out zones without walls. The living area, with its corner glazing onto a garden tree, sits under a different part of the ceiling than the kitchen, so each part of the open plan feels distinct. A linear MVHR vent is set neatly into the ceiling planes, a reminder that the joy here is built on serious services.

Pastel Rooms Upstairs

The refurbishment carries the playful palette into the existing house. Pastel colours mark out different spaces, and pink is reserved for particular objects and zones: a niche behind an oak headboard, a bathroom with vertical tiles and a freestanding basin. It is a confident use of colour that treats the brief's request for joy as a design requirement, not an afterthought.

Behind these finishes sits a fabric-first upgrade. Insulation and airtightness were improved, the house became all-electric, and an air-source heat pump now supplies heating and hot water. According to RIBAJ data, annual operational emissions fell from 30.09 to 13.63 kgCO₂e/m², a reduction of more than half.

Plans and Drawings

The site plan shows how ordinary the plot is: one narrow strip among rows of terraces. The existing and proposed plans show that most of the change comes from opening up the rear ground floor, not from adding much floor area. The long section is the most revealing drawing. In it, the stepped sloping roofs pull light deep into the plan and give the kitchen a height the original terrace never had.

Why This Project Matters

Sawtooth House shows that the most common domestic project in London, the rear extension, can still carry a real idea. Instead of choosing between pastiche and anonymous glazing, Francesco Pierazzi Architects looked to the area's industrial past and found a roof form that solves a practical problem: getting balanced daylight into a deep, narrow plan. Character and performance come from the same move.

It also matters as a retrofit case study. With only 15 m² added, most of the environmental gain comes from upgrading what already existed: the fabric, the heating system, ventilation and water management. The planning story is a useful reminder that contextual design does not have to mean traditional design, and that persistence on appeal can protect a better building. For homeowners and architects facing the same terrace and the same brief, this is a clear model.

Sawtooth House by Francesco Pierazzi Architects, Kingston upon Thames, United Kingdom. Area: 180 m². Completed: 2024. Photography: Peter Molloy.

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