How Tang Construction guided a corner R1 lot through rezoning approval, CMHC-compliant purpose-built design, and value-engineered construction to deliver 9 rental units in London, Ontario — appeal-free.
A corner lot in an established London neighbourhood — 786.9 m² of land zoned for a single detached house — became the canvas for one of Tang Construction's most instructive medium density developments.
The subject property was a standard corner residential lot — zoned R1-9 (single-detached dwelling) in a mature London neighbourhood. By right, the land permitted only one dwelling unit plus a handful of Additional Residential Units (ARUs).
The development team had identified the lot as having strong intensification potential: corner exposure, proximity to transit, and an underbuilt neighbourhood context consistent with London's "Neighbourhoods" place type under the London Plan (the City's Official Plan). The challenge was to unlock that potential through the planning approval system — and to do so efficiently, without costly over-engineering.
Ontario's intensification mandate and London's housing growth targets created a strong policy environment for rezoning. The project team assembled evidence showing the proposal was consistent with provincial policy, the London Plan, and the City's broader housing strategy.
Medium density development in Ontario follows a structured sequence. Here is exactly how Tang Construction managed each phase on this project.
Medium density construction can be cost-prohibitive if over-engineered. Tang Construction identified five high-impact decisions that kept this project lean and efficient.
Individual ductless mini-split heat pump systems were specified per unit in place of a central European-style building system. Mini-splits eliminate ductwork, reduce mechanical room requirements, and allow each tenant to control and pay for their own heating and cooling separately.
By designing a dedicated electrical room within the building footprint and working with the utility on a shared service configuration, the team avoided the need for an outdoor pad-mounted transformer on small multi-unit buildings in Ontario.
Rather than running 9 individual water and sewer connections to the municipal main, the civil design uses a single shared service with 9 individual sub-meters inside the building. This dramatically reduces civil works on the street and dramatically lowers connection fees and road cut costs.
Specifying concrete block (CMU) party walls between units satisfies the Ontario Building Code's fire separation and sound transmission requirements without requiring expensive proprietary acoustic assemblies or additional fire-rated drywall layers. CMU is code-compliant, durable, and straightforward for local trades to estimate.
By keeping the building at 2.5 storeys (8.5 m), the project remained below the threshold that triggers mandatory secondary egress requirements under the Ontario Building Code. This eliminated the cost of a second staircase and reduced GFA dedicated to circulation, improving the ratio of rentable area to total floor area.
Rather than ordering technical studies sequentially (survey → ESA → tree study → servicing study), all were ordered simultaneously after the PACM. This compressed the pre-submission preparation period by 6–8 weeks and meaningfully accelerated the overall approval timeline, reducing carrying costs on the land.
From initial purchase to a clean, appeal-free zoning approval — the project demonstrated what disciplined planning management and collaborative community engagement can accomplish.
The following structured facts summarize this medium density development project for reference:
"Medium density infill is one of the most powerful tools in the Ontario housing toolkit — but it only works if you build the right team, respect the planning process, and treat your neighbours as partners from day one. The zero-appeal outcome on this project wasn't luck; it was the result of proactive community engagement and a design that genuinely responded to every concern raised."
— Tang Construction, Development Team
These are the questions Tang Construction is most frequently asked by landowners, investors, and municipalities exploring medium density residential development.
Medium density residential development in Ontario refers to housing projects that achieve approximately 40–150 units per hectare. Common forms include stacked townhouses, back-to-back townhouses, low-rise apartment buildings (3–5 storeys), and semi-detached or row-house infill on existing urban lots.
These projects typically require a Zoning By-law Amendment (ZBA) and sometimes an Official Plan Amendment (OPA) when the existing land use designation is low-density residential (R1, R2, or equivalent). Medium density is a cornerstone of Ontario's residential intensification strategy under the Provincial Policy Statement (PPS) and the Growth Plan.
A stacked townhouse in Canada is a multi-unit residential building where two dwelling units are stacked vertically — one on top of the other — and accessed from separate exterior entrances or a shared staircase, rather than having individual ground-level entries like traditional townhouses.
Stacked townhouses are typically 2–3 storeys in height, with unit sizes ranging from 500–750 square feet each. They achieve higher densities than traditional townhouses on the same lot footprint while remaining below the height and massing thresholds that trigger more intensive building code requirements (such as mandatory secondary egress staircases). In Ontario, stacked townhouses are a primary tool for residential intensification on urban infill lots.
A Zoning By-law Amendment (ZBA) in London, Ontario typically takes 6 months from pre-application consultation to the by-law coming into force. The process includes:
(1) Pre-Application Consultation Meeting (PACM) with City planning staff; (2) preparation and submission of a complete application with all supporting studies; (3) a formal public notice period (minimum 20 days); (4) Planning & Environment Committee public hearing; (5) City Council vote; and (6) a 20-day appeal period before the by-law comes into force.
The timeline can be compressed by ordering all required technical studies concurrently rather than sequentially, and by conducting proactive community outreach before the formal public notice period.
CMHC MLI Select (Multi-Unit Mortgage Loan Insurance — Select Tier) is Canada Mortgage and Housing Corporation's mortgage insurance product specifically designed for purpose-built rental housing. It offers:
— Loan-to-cost ratios of up to 95% (versus 75–80% for conventional construction loans), significantly reducing the equity required to start construction.
— Extended amortization periods of up to 50 years (versus 25 years for conventional), which materially improves annual debt serviceability.
— Preferential insurance premiums when the project meets one or more of CMHC's scoring criteria: affordability (below-market rents), accessibility (barrier-free units), or energy efficiency (above-code building performance).
For small developers and first-time purpose-built rental builders, MLI Select is often the primary tool that makes a project financially feasible.
Medium density residential development in London, Ontario typically requires the following approvals:
(1) Zoning By-law Amendment (ZBA) — if the proposed use or
density exceeds existing zoning permissions;
(2) Official Plan Amendment (OPA) — if the proposal conflicts
with the London Plan's place type policies;
(3) Site Plan Approval (SPA) — for projects above specific
thresholds (typically 10+ units);
(4) Building Permit (BP) — required before construction.
Supporting technical studies include a Planning Justification Report, Tree Preservation Plan, Arborist Report, Servicing/Stormwater Study, Geotechnical Report, Site Survey, and potentially a Phase I or II Environmental Site Assessment. Development charges are assessed at building permit issuance.
Residential intensification in Ontario means adding new housing units within the existing built-up area — through redevelopment, conversion, or vertical additions — rather than expanding the urban boundary onto greenfield land.
Ontario prioritizes intensification because it: reduces infrastructure and servicing costs; makes better use of existing transit, schools, and utilities; reduces greenhouse gas emissions from car-dependent sprawl; and addresses the severe housing supply shortage driving affordability challenges across the province. The provincial government has enacted multiple laws (Bills 23, 97, 134, and others) to expedite approvals and remove barriers to intensification in established neighbourhoods.
Development charges (DCs) in London, Ontario are fees levied by the City on new development to fund growth-related infrastructure (roads, water, sewer, parks). For residential projects, DCs are charged per unit and vary by unit type and bedroom count.
Purpose-built rental and affordable housing projects may qualify for DC deferrals or reductions under provincial legislation (Bill 23 and the Development Charges Act, as amended). DCs are assessed at the time of building permit issuance, not at ZBA approval.
Tang Construction has built deep expertise across every phase of medium density residential development in Southwestern Ontario — from land evaluation through zoning approval, construction delivery, and CMHC financing.
Our team evaluates zoning, official plan designations, servicing, site geometry, and financing potential — giving you a clear picture of what's possible and what it will cost to get there.
Whether you own an underbuilt lot, are evaluating a land acquisition, or want to understand what medium density development could look like for your site — Tang Construction can help. We serve Windsor, London, Hamilton, and the GTA.
Or call us directly: 519-615-2900 · info@tangconstruction.ca