To launch her firm, assemblage studio, architect Claudia Campeau chose to begin with a foundational project—one that is both deeply personal and revealing of her design approach: the transformation of her Montreal duplex into a single-family home.

Located in the Villeray neighbourhood, the Lilac House embodies a sensitive approach to residential renovation, where architecture becomes a tool for adapting to family life, the passage of time, and the very real constraints of the existing building.

More than just a personal project, this transformation also represents a clear stance: in the face of today’s environmental and urban challenges, thoughtful renovation stands as a sustainable alternative to new construction. The project proposes a careful and rigorous metamorphosis, in which every intervention is grounded in an intimate understanding of the space.

A home designed for the long term

Before undertaking the renovation, Claudia and her family lived in the duplex for nearly three years. This extended period of immersion allowed the architect to gain a nuanced understanding of the site’s qualities and limitations—and, above all, to anticipate its future evolution.

"We really thought about the house in terms of how it could adapt to our needs over time," explains the architect. "I couldn’t design it just for the next five years, because the children will grow up."

Designed to evolve, the project incorporates a flexibility essential to family life. Thus, certain rooms can change function over time—guest room, office, workshop, and more.

This approach addresses a contemporary challenge: creating homes capable of supporting multiple life stages without requiring major future renovations.

Turning constraints into openness

With a facade barely 21 feet wide, the 1924 duplex presented significant constraints: narrow, attached to neighboring properties on both sides, poorly insulated, and marked by successive alterations over time. The project is built around a series of precise gestures aimed at maximizing natural light and the perception of spaciousness.

On the ground floor, the space is organized into three successive zones. At the front, a functional zone brings together the entry, a closed office, and a powder room. In the center, the minimalist kitchen acts as a white canvas, punctuated by a large island and a staircase, both crafted in white oak. At the rear, the living and dining areas open generously onto the courtyard through a large glazed opening, beneath a ceiling with exposed cedar joists and decking.

The southwest-facing courtyard, marked by a mature lilac tree, is now intimately connected to the living spaces. A terrace topped with a pergola eventually covered in greenery— inspired by the vine supports typical of the neighbourhood with Portuguese roots—filters summer light while allowing winter sun to pass through, inviting nature into everyday life.

Careful coordination of mechanical systems and structure further enhances the sense of openness: ventilation ducts and the kitchen hood are integrated within the depth of the ceiling joists to preserve the original ceiling height, while a system of steel beams transfers structural loads and clears circulation paths.

The luminous heart of the house

The central staircase, a true centerpiece of the project, is crowned by a skylight flanked by a striking curve which diffuses natural light down to the basement. As a result, every room benefits from natural light, including the ground-floor powder room, whose shower is illuminated by a frosted window overlooking the staircase. Upstairs, the bathroom features a skylight whose curves echo those of the staircase, lending softness and comfort to the space.

Sustainability as a guiding thread

The Lilac House places sustainability at the core of its design ethos, both by preserving or restoring certain elements, and by considering the building’s long-term maintenance.

The front balconies have been restored in white cedar, with new ornamental steel columns inspired by the original local typology.

Significant efforts have also been made to preserve and enhance as many original building elements as possible: the brick from the rear façade was carefully dismantled, cleaned, and reinstalled; portions of the existing timbers were sanded and cut down to create shelving in the ground-floor office; and the sole original interior door from the duplex was preserved and relocated to one of the children’s bedrooms.

The new floors, staircase, and millwork are made from local materials and crafted by regional artisans, as were several light fixtures, including those from Lambert et fils and Luminaires Authentik.

Overall, the project favours robust, easily repairable solutions that respect the building’s life cycle, where each decision contributes to reducing the project’s environmental footprint.

Through its meticulous and pragmatic approach, The Lilac House illustrates how renovation can become a true community project: offering sustainable, comfortable, and meaningful living environments.