Home Additions in Toronto & the GTA
Experts for Home Addition in Toronto and the GTA
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.
Stay in the Neighbourhood You Love
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.
Why Us
What Sets Us Apart
Fixed-price contract locked before construction; no cost-plus billing.
In-house architects, engineers, designers, and builders.
Permits and zoning handled completely by our team.
Dedicated project coordinator throughout construction.
Structural guarantee on every project we build.
What We Build
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.
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 neighbourhoods 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.
Talk to us about your project.
Free, no obligation. You get a clear, fixed price.
The Grand Design Build Difference
Why Homeowners in Toronto Choose Us
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.
Structural Guarantee
We stand behind our work with a 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.
Our Process
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.
We Handle All Of It
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.
Areas We Serve
Home Additions Across Toronto
We build throughout Toronto and the GTA. These are the neighbourhoods we work in most.
Homeowner Reviews
What clients say about this service.
“I had a really good experience working with Grand Design Build on my home renovation and rear addition project. Their team was professional, knowledgeable, and easy to work with throughout the process.”
Hasan G., Renovation & Addition“Grand Design Build did a great job on our renovation. Their team was organized, kept us informed through each step, and also delivered quality work. Reliable with timelines and very clear about costs and materials.”
Lima Rodwesko, Renovation“From day one, the team listened, understood, and genuinely cared about making things right. They walked with us through every step and educated us, and honestly, the finished home speaks for itself.”
Mark F., Full Home RenovationFrequently Asked Questions
Everything you'd ask before committing.
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.
The timeline varies by project type. A rear main-floor addition typically takes 4 to 6 months from permit approval to handover. A full second-storey addition on a bungalow typically runs 7 to 10 months. Design and permitting add 2 to 4 months before construction begins. Your project coordinator will give you a specific schedule before you sign your contract, and milestones are tracked throughout.
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.
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.
The terms are used interchangeably. Both refer to adding new square footage to an existing home by building outward, a rear or side extension, or upward, a second storey addition.
Three things. We're HCRA licensed, required for this type of structural work in Ontario. We offer fixed-price contracts, so your quote is your price. And we back every addition with a structural guarantee.