Experts for Home Addition in Toronto and the GTA
Second Storey Home Additions, Rear Extensions & More
From rear additions to full second-storey builds, Grand Design Build manages everything in-house: design, permits, engineering, and construction. One team, one contract, zero guesswork.
Why a Home Addition?
Moving is expensive, disruptive, and often unnecessary. A well-planned home addition can give you the space you need, a new master suite, a bigger kitchen, an extra bedroom, or a full second storey, without leaving the neighbourhood where your family has roots.
Grand Design Build has delivered home additions across Toronto and the GTA since 2010. We handle the entire project under one roof: a fixed-price contract, with permits handled in-house and a dedicated coordinator running the schedule from the first site visit through to handover.
What Sets Us Apart
✦ In-house architects, engineers, designers, and builders
✦ Permits and zoning handled completely by our team
✦ Dedicated project coordinator throughout construction
✦ 7-year structural guarantee on every project we build
If you’re weighing whether to add on or move, we’ll give you a straight answer at the consultation.
Types of Home Additions
Not every home needs the same kind of addition. The right approach depends on your lot, your existing structure, your municipality’s zoning rules, and what the addition is actually for. A family adding two bedrooms has different options than a homeowner trying to widen a narrow main floor. We’ve built all of it.
Second Storey Additions
Convert a bungalow into a two-storey home. Add bedrooms, bathrooms, and a primary suite without reducing your yard space. Ideal for growing families in established Toronto neighborhoods where lots are too valuable to build out on.
Rear Addition & Main-Floor Extensions
Extend the back of your home to expand the kitchen, dining area, or living room into a larger, open-concept footprint. Popular for Toronto semi-detached and detached homes.
Side Additions & Extensions
If your lot allows, a side addition can add a bedroom, mudroom, bathroom, or expanded entryway, often the most cost-effective way to add square footage.
Works particularly well in semi-detached homes where one side is exposed.
Attic Conversions & Dormers
Unlock unused space above your existing ceiling. Attic conversions and dormer additions can yield a full bedroom, bathroom, and study without touching the main structure.
Garage Additions & Over-Garage Suites
Build a new detached or attached garage, or add a studio suite above an existing garage. Ideal for additional living space, a home office, or rental income.
Basement Extension & Underpinning
Lowering and reinforcing an existing foundation to create a full-height, functional basement. We manage excavation, structural engineering, waterproofing, and interior finishing, everything.
Our Home Addition Projects
Why Homeowners in Toronto Choose Us
We built our reputation on three things: delivering exactly what we promised, charging exactly what we quoted, and keeping clients informed throughout the entire process.
✦ Fixed-Price Contract: Our contracts are fully itemized with allowances explained upfront. You know the final number before you sign anything. No cost-plus billings, mid-project surprises, or hidden charges.
✦ One In-House Team: Our contracts are fully itemized with allowances explained upfront. You know the final number before you sign anything. No cost-plus billings, mid-project surprises, or hidden charges.
✦ HCRA licensed: Grand Design Build is licensed by the Home Construction Regulatory Authority of Ontario, a legal requirement for builders doing this type of work.
✦ 7-year structural guarantee: We stand behind our work with a 7-year structural guarantee on every addition we build. Our quality control process includes documented inspections at every critical milestone.
✦ Permits & Approvals Managed: Navigating Toronto’s zoning bylaws, setback requirements, angular plane regulations, and Committee of Adjustment processes is complex. We handle all of it.
✦ Dedicated project coordination: You’ll have one named point of contact who manages the schedule, the trades, and the construction. Regular updates, documented milestones, and a direct line of communication.
✦ Operating since 2010. Over a decade of additions, extensions, and structural builds across Toronto, North York, Forest Hill, Rosedale, Etobicoke, Oakville, and Mississauga.
From Home Addition Idea to Final Move-In
Complimentary Consultation
We meet at your home, review the existing conditions, and discuss your goals, wish list, and timeline. We assess feasibility and give you an honest early read on scope and budget range.
Zoning & Feasibility
Our team reviews by-laws for your specific address: setbacks, height limits, lot coverage, angular plane, and FSI. We identify whether your project is as-of-right or requires a variance.
Design & Fixed-Price Quote
Our in-house architects develop concept drawings, and our designers walk you through finishes and materials. Once you've approved the design, we lock in your fixed-price contract.
Permit-Ready Drawings & Approvals
We produce full architectural and structural drawings, coordinate engineering, and manage the City of Toronto permit submission and approval process, including any Committee of Adjustment hearings.
Construction & Trade Management
Our on-site supervisor coordinates all trades, manages the schedule, and performs documented quality checks at each milestone. You receive regular updates from your project coordinator.
Final Walkthrough & Handover
We walk through every detail together, address any deficiencies on the spot, and deliver your home with full documentation; permits, warranties, and maintenance guides included.
READY TO DISCUSS YOUR PROJECT?
Permits & Approvals
Toronto’s permitting and zoning process is detailed and time-sensitive. Our team manages every submission, inspection, and approval, so you don’t have to.
Zoning Review
We verify setbacks, height, lot coverage, FSI, angular plane, and parking requirements specific to your property and addition type.
As-of-Right vs. Minor Variance
We confirm whether your project qualifies as-of-right or requires a minor variance, and represent you at the Committee of Adjustment if needed.
Architectural & Structural Drawings
Our in-house architects and structural engineers produce complete, permit-ready drawing packages — no third-party coordination required.
City Permit Submission & Follow-up
We submit to the City, track your application, respond to examiner comments, and push the process forward to avoid unnecessary delays.
Heritage, TRCA & Tree Coordination
For properties in heritage areas, ravine-adjacent lots, or those with significant trees, we coordinate all additional approvals and protective measures.
Construction Inspections & Closeout
We schedule and manage all required City inspections throughout construction and obtain final occupancy sign-off when the project is complete.
Do I Need a Permit for My Addition?
Yes, all home additions in Toronto require a building permit. The process varies depending on whether your project is as-of-right under current zoning or requires additional approvals.
Many projects are straightforward and receive permits without hearings. Others require a minor variance application, a process we manage completely on your behalf, including representation at the Committee of Adjustment.
The short answer: don’t worry about it. We’ve guided over 250 addition projects through Toronto’s approvals process. Your coordinator will explain exactly what’s needed for your specific project from day one.
What Our Clients Say About Our Services
Frequently Asked Questions
Do I need a building permit for a home addition in Toronto?
Yes, all home additions require a building permit. Many projects are as-of-right, meaning they comply with existing zoning rules and can be permitted without additional hearings. If your project exceeds lot coverage, setbacks, height limits, or FSI limits, a minor variance application is required. Grand Design Build manages the entire permit and approval process, including Committee of Adjustment representation when needed.
How long does a home addition take?
The timeline varies by project type. A rear main-floor addition typically takes 4–6 months from permit approval to handover. A full second-storey addition on a bungalow typically runs 7–10 months. Design and permitting add 2–4 months before construction begins. Your project coordinator will give you a specific schedule before you sign your contract, and milestones are tracked throughout.
Is a second-storey addition better than a rear addition for my bungalow?
It depends on your lot and goals. Second-storey additions maximize square footage without reducing yard space, ideal for smaller lots. Rear additions are often simpler structurally and less disruptive to live in during construction. Many homeowners combine both. We’ll review your property and zoning during the initial consultation and recommend the option that gives you the best outcome for your budget.
Can I stay in my home during the addition?
In most cases, yes, though there will be periods of disruption, particularly when structural work is underway or when the roof is open during a second storey build. We plan phasing to minimize disruption and give you advance notice of the most intensive periods.
What is the difference between a home addition and a home extension?
The terms are used interchangeably. Both refer to adding new square footage to an existing home by building outward (rear or side extension) or upward (second storey addition).
Does Grand Design Build handle zoning and setback requirements?
Yes. Our in-house design team reviews zoning bylaws, lot coverage limits, and setback requirements before we finalize any design. We flag potential issues early so they don’t become problems during permitting.
What makes Grand Design Build different from other home addition contractors in Toronto?
Three things:
- We’re HCRA licensed (required for this type of structural work in Ontario)
- We offer fixed-price contracts (your quote is your price)
- We back every addition with a 7-year structural guarantee.
Most contractors offer none of these. We offer all three.