Transforming a Downtown Bungalow into a Modern Multiplex at 81 Massey Street, Toronto

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Introduction

This Four Unit Multiplex Toronto project showcases how Q Engineering is transforming an existing single-storey bungalow into a modern, structurally independent four-unit residential building. Located in one of Toronto’s most dynamic residential areas, the design maximizes space, comfort, and long-term value while preserving as much of the existing structure as possible.

This project highlights Q Engineering’s expertise in structural design, architectural coordination, and foundation reinforcement, all while meeting the City of Toronto’s strict residential building standards.

Project Overview

Type: Residential Multiplex (Conversion & Addition)
Location: 81 Massey Street, Toronto, ON
Scope: Structural and architectural design, underpinning, addition of second and third floors, and rooftop terrace
Client Goal: To convert an aging bungalow into a modern four-unit residence while preserving as much of the existing structure as possible.

The client, Mr. Nadjib Aouchiche, envisioned a multi-unit home that combines functionality, durability, and future flexibility. With limited lot space in Toronto’s downtown core, the project required a smart structural approach — one that could accommodate multiple residential units while reinforcing the original foundation.

Engineering Challenges

Redeveloping an older bungalow into a three-storey multiplex posed several complex structural challenges:

  • Preserving the existing structure: The original bungalow’s framing and foundation couldn’t carry additional loads from the new upper floors.

  • Minimizing disruption: The design needed to limit demolition and excavation to preserve the basement and existing main floor.

  • Creating a new independent frame: A modern structure had to be introduced without overloading the old one.

  • Designing for future adaptability: The client requested that the new foundation and framing support a potential half-floor and rooftop terrace in the future.

  • Logistical coordination: The property’s tight downtown footprint required careful planning for site access, underpinning, and excavation.

Q Engineering’s Solutions

Q Engineering redesigned the project from the ground up — literally. Our team replaced the initial conventional framing concept with a steel-and-concrete hybrid structural system, ensuring strength, flexibility, and longevity.

Independent Structural Framing

  • Introduced HSS steel columns (6”x6” and 5½”x5½”) anchored to reinforced concrete footings in the basement.

  • Created a self-supporting steel skeleton that passes through the entire height of the building — from the basement to the rooftop — allowing the new second and third floors to sit independently of the original structure.

  • Used W8x15–W8x35 beams and LVL joists to distribute loads evenly while maintaining interior openness.

Foundation & Underpinning

  • Underpinned and reinforced the existing basement to achieve a legal 8-foot ceiling height and improve load-bearing capacity.

  • Added new footings (4’–5′ wide) designed to support potential future vertical expansion.

  • Installed a sump pump and drainage system to manage groundwater and prevent moisture intrusion.

Efficient Multi-Unit Layout

Each of the four levels — basement, main, second, and third floors — was designed with mirrored layouts for construction efficiency and cost reduction.

  • Unit 1 (Basement): Two bedrooms, open-concept living space, large egress windows, and independent mechanical systems.

  • Units 2–4: Open-concept living/dining/kitchen areas, multiple bedrooms, and private access to the rooftop terrace.

  • Rooftop: Reinforced structure capable of supporting a hot tub, outdoor kitchen, and garden area.

Architectural Coordination

Additionally, Q Engineering worked closely with the architectural designer. Together, the team ensured all new framing, egress routes, and privacy walls met Ontario Building Code (OBC 2012) standards.
Every connection, beam, and post was verified for constructability — balancing safety, aesthetics, and cost efficiency.

Outcome & Expected Impact

The redesigned structure is currently in the advanced design and permit phase, representing a modern reimagination of downtown residential infill.
The project demonstrates:

  • A scalable and durable design that supports future expansions.

  • A reduced construction timeline through prefabricated steel framing.

  • Compliance with OBC and City of Toronto permit requirements.

  • Enhanced property value through conversion from a single dwelling to a four-unit income property.

Overall, the 81 Massey Street project reflects Q Engineering’s commitment to innovation, precision, and helping homeowners unlock the full potential of their properties.

Conclusion

The 81 Massey Street multiplex project is a testament to how strategic structural engineering can transform outdated properties into modern, high-performance residences.
Whether it’s an addition, renovation, or a complete redevelopment, Q Engineering provides the expertise, design accuracy, and technical oversight to make every residential project a success — from concept to construction.