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Before you build

Could your property support a triplex or fourplex?
Start with feasibility.

What is permitted, what the site can support, and whether the numbers work: three questions worth bringing together before you commit.

A triplex or fourplex can look straightforward on a sketch. Before committing to a design or construction budget, there are three separate questions to answer: what is permitted, what the site can support, and whether the full project makes financial sense. An answer to one does not settle the others.

For an owner exploring development for the first time, a feasibility review brings those questions together before the commitments become larger.

Permission is one part of the picture.

Ontario’s zoning guidance explains that municipal bylaws regulate land use and matters such as building location, height and setbacks.[1] Building permit review checks the proposed work against the Building Code and other applicable requirements.[2]

A general statement about “more units being allowed” is only a starting point. The property, proposed building and applicable local requirements still need to be considered together.

An early review helps identify which questions need a planner, designer, municipality or another specialist before the owner commits to a particular approach.

The property has to support the idea.

A development opportunity involves more than the space visible above ground. In its guidance for additional residential units, the City of London identifies the need for water and sewer services to accommodate the proposed increase in development.[3]

An assessment of your property should bring those practical constraints into the conversation alongside the building concept. The aim is to identify issues that could change the scope, cost or next steps while the proposal is still being shaped.

The construction price is not the whole budget.

CMHC’s affordable-housing feasibility guidance distinguishes between the capital budget, the operating budget after completion, and cash flow during construction. Its capital-budget categories include construction, purchase costs, fees, permits and carrying costs.[4]

For your proposed triplex or fourplex, the useful question is broader than “What will it cost to build?” It is whether the complete project, its funding needs and its expected operating results fit together.

Boldhaven’s detailed feasibility service is designed to make those assumptions visible. We help you consider the financial picture and the effect of changing assumptions, so the decision to proceed, revise or pause is one you understand.

Choose the support that fits the decision.

You do not need to commit to a full development-management engagement to begin.

A property review provides an initial assessment of the opportunity and its key constraints. Detailed feasibility takes a closer look at the numbers and risks. If the project proceeds, development management is an optional service to coordinate the team, track the budget and support delivery through handover.

Each stage has an agreed scope. Specialist professionals remain responsible for their own work, and approvals, financing and investment results cannot be guaranteed.

Sources & context

  1. Ontario · Zoning bylaws
  2. Ontario · Building permits
  3. City of London · Additional Residential Units
  4. CMHC · Development Checklist for Affordable Housing: Feasibility

Sources reviewed 9 November 2026. CMHC’s checklist is used for general budgeting concepts, not financing eligibility. This article does not establish what is permitted or financially viable on a particular property.

PUT THE IDEA IN CONTEXT

What could this mean
for your property?

Start with a conversation about what you own
and what you want to achieve.

LET’S START WITH YOUR PROPERTY

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have in mind?

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