Duplex, Triplex, Fourplex & Multi-Unit Design & Conversions in Ontario

DESIGN & BUILD YOUR LEGAL DUPLEX, TRIPLEX OR MULTIPLEX FASTER & SMARTER WITH ONE DEDICATED TEAM

Start-to-Finish: Planning, Drawings & Construction.

Most duplex or triplex conversions go off the rails because of permits, zoning confusion, poor drawings, uncoordinated contractors, surprise code requirements, and endless back-and-forth between designers and builders.

Suite Builders eliminates all of that. By combining design + permit drawings + construction under one roof, we keep your project moving, compliant, and profitable—whether you’re turning a single-family home into:

  • Legal duplex
  • Full triplex
  • Fourplex conversion
  • Multi-unit building

One team, one contract, one process. Faster approvals, fewer surprises, and no costly miscommunication.

Proudly serving homeowners, developers and real estate investors across Southern Ontario, including: Hamilton, Niagara Falls, St. Catharines, Welland, Oakville, Burlington, Kitchener, Waterloo, Cambridge, Guelph, Wellington County, Brantford, Brant County, Woodstock, Oxford County, Norfolk County, Haldimand County, London, Middlesex, St. Thomas, Elgin County and surrounding areas.

Project Highlight: Turning A Single Family Home into a Triplex in Simcoe, Ontario

Our team successfully converted a single-family home into three separate, Ontario Building Code-compliant living spaces by utilizing the existing attic loft for a beautiful, self-contained unit with ample natural light. Multi-unit conversions are becoming increasingly popular choices for multigenerational living, investment properties, student housing and aging-in-place, by maximizing under-utilized space—without expanding a home’s footprint.

duplex contractor norfolk county
triplex builder norfolk county
duplex builder norfolk county
attic conversion hamilton
attic conversion brantford
duplex builder hamilton
triplex builder hamilton
fourplex builder kitchener
duplex builder kitchener-waterloo
duplex triplex builder kitcher-waterloo

Ontario’s Growing Demand for Multi-Unit Housing — And Our Complete Duplex, Triplex & Fourplex Solutions

Ontario’s housing market is shifting fast. Homeowners and real estate investors are turning single-family houses into duplexes, triplexes, fourplexes and multi-unit buildings to meet rising rental demand and improve property value.

Suite Builders fully integrated design-build system for legal multi-unit housing handles zoning reviews, architectural drawings, permit submissions, and full construction under one coordinated team. We’re experts in all of the legal requirements of multi-unit buildings in Ontario, including:

  • What are the zoning rules for building a duplex, triplex or fourplex in Ontario?
  • What building code and fire separation requirements apply to legal multi-unit conversions?
  • What ceiling heights, egress and natural light requirements must a legal unit meet?
  • What drawings are required to get a building permit for a duplex, triplex or fourplex?
  • What inspections and approvals are needed to finalize a legal multi-unit dwelling?

Our single-team system ensures your duplex, triplex or fourplex is built faster, legally compliant, and without the usual renovation headaches, trusted by investors and homeowners across Ontario.

For a list of everything you need to know about adding a second living unit to your property in Ontario, click here.

Multiplex development feasibility review with permit drawings and construction planning

Legal Multi-Unit Homes That Outperform

Whether building a multifamily investment property, increasing property value, or creating a living space for multi-generational living or aging-in-place, a duplex, triplex, fourplex or multiplex conversion or new build is becoming an increasingly popular solution to housing affordability and family wealth building.

1. Legal Duplexes in Ontario

Create a high-ROI, code-compliant second unit with proper fire separation, egress, HVAC design, and permit-ready drawings. Perfect for homeowners, BRRRR investors, or multi-gen families.

2. Triplexes and Fourplexes

Offer exceptional cash flow and strong cap rate boosts. Maximize density and long-term revenue with custom-designed layouts, code compliance, and full project management.

3. Multi-Unit (2–8 Units)

For investors looking to scale, we design and build multi-unit conversions up to 8 units that pass inspections the first time—saving months of delay and thousands in holding costs.

FREQUENTLY ASKED QUESTIONS

Costs vary by existing structure, layout, and code requirements. Suite Builders provides fixed-price budgeting right from the start to help investors calculate ROI and BRRRR performance.

Yes. Any legal duplex, triplex, or multi-unit conversion requires a building permit. Municipalities also enforce parking, zoning setbacks, ceiling height requirements, egress, and fire-code separations. Suite Builders manages the entire permit process for you.

Not always—zoning, lot size, parking rules, and structural conditions all matter. Our feasibility review determines if your property is eligible for a duplex, triplex, fourplex, or higher-density multi-unit conversion before design begins.

The top delays come from incomplete drawings, incorrect fire-separation details, missing HVAC design, zoning issues, and permit resubmissions. Suite Builders prevents these issues by coordinating design and construction from day one.

The fastest route is working with a design-build company that handles zoning, drawings, permits, and construction under one team. This eliminates the most common delays—designer–contractor miscommunication, permit revisions, and uncoordinated trades.

Why Choose Suite Builders TO BE YOUR Duplex, TRIPLEX, FOURPLEX OR MULTI-UNIT BUILDER?

When it comes to designing and building legal accessory dwelling units (ADUs), additional residential units (ARUs), secondary suites and complete multiplex conversions, Suite Builders offers what many firms cannot: a fully integrated design-build solution that removes the headaches, miscommunications and unnecessary delays that often plague these projects.

Our specialties include:

  • Finished basement apartments & legal in-law suites
  • Duplexes, triplexes, fourplexes & multiplex conversions
  • Garage conversion apartments & coach houses
  • Garden suites & tiny homes
  • Backyard homes & laneway suites
  • Home additions & multi-unit conversion of existing homes
  • Seasonal farm worker housing & bunkhouses

With a single accountable team managing everything—from initial site feasibility and building permit drawings to construction hand-over—you avoid the typical pitfalls of coordinating multiple contractors, dealing with permit rejections, scope creep, or code non-compliance.

If you’re a homeowner or investor in Ontario ready to build income-producing property, maximize value, or add flexible living space, contact Suite Builders today for a free discovery call and start your project the right way—on time, on budget, and code-compliant.