Adding a second storey or a full dormer conversion can double your living space without moving. For many Toronto bungalows and one-and-a-half-storey houses, a top-up delivers new bedrooms, a primary suite, a kids’ bath, and laundry while keeping your neighbourhood and yard. This guide walks through feasibility, structure, design, HVAC, exterior details, and realistic budgets so you can plan with confidence.

Quick feasibility checks

1. Lot and zoning context: Note lot frontage, depth, setbacks, and height limits. Corner lots and mature trees can influence massing and access.
2. Foundation health: We assess cracks, settlement, and footing size. A top-up adds load, so foundations must be sound or locally reinforced.
3. Structure below: Verify main-floor walls and beams that will carry new load paths. Some interior walls may become bearing and need new beams or posts.
4. Access and staging: Plan crane access, scaffolding locations, and material deliveries on tight city streets.
5. Neighbour impacts: Sun, privacy, and drainage matter. Early conversations keep projects neighbourly.

Smart space planning for the new level

• Primary suite: Add a quiet bedroom, a walk-in closet, and a bright ensuite with a curbless shower.
• Kids’ zone: Two similar-sized bedrooms with a shared bath and a linen closet cut morning friction.
• Laundry upstairs: A small stacked unit with a floor drain and sound-insulated walls saves steps.
• Home office or flex room: A compact office with a pocket door can double as a nursery or guest room.

Stairs: the backbone of the layout

• Location: Stairs often stack over the existing stairs or run above a hallway to save space.
• Comfort: Aim for 10 to 11-inch treads and 7 to 7.75-inch risers for comfortable climbs.
• Light: Add a skylight or sun tunnel above the landing to brighten the core of the home.
• Sound and safety: Solid treads, continuous handrails, and low-profile runners feel quiet and secure.

Structure and envelope done right

• Framing: New floor system and exterior walls framed with engineered lumber for longer spans and straighter lines.
• Shear and uplift: Tie the new level to the existing walls with hold-downs and proper sheathing nailing patterns for wind resistance.
• Insulation: Continuous exterior insulation plus a ventilated rainscreen boosts comfort and stops drafts.
• Windows and doors: Choose high-performance units sized for egress and natural light. Keep bedroom window heights consistent for a calm facade.

HVAC and electrical planning

• Heating and cooling: Extend or replace the system with a properly sized ducted heat pump or a high-efficiency furnace plus AC. Consider dedicated zoning for upstairs comfort.
• Ventilation: Add an HRV or ERV with supplies to bedrooms and returns in the hall.
• Electrical: Plan a subpanel for the addition and plenty of outlets, data drops, and ceiling fan boxes in bedrooms.
• Plumbing: If adding a bath and laundry, stack wet walls for shorter runs and quieter operation.

Exterior style and curb appeal

• Keep it cohesive: Match or refresh cladding on the main floor so the addition looks intentional, not tacked on.
• Rooflines: Simple gables or low-slope shed roofs reduce complexity and look modern.
• Entry upgrade: A new canopy, steps, and lighting rebalance the facade.
• Windows: Align upper windows with lower ones for rhythm and better proportions.

Permits, approvals, and timelines

• Permits: Architectural and structural drawings are required. Heritage properties or Committee of Adjustment approvals may add review time.
• Inspections: Expect framing, insulation, mechanical, and final inspections.
• Timelines: Design 4 to 12 weeks. Permits 6 to 14 weeks, depending on reviews. Construction 12 to 24 weeks based on scope and season.

Budgets for Toronto top-ups

Every home is different. These ranges help with early planning and will be refined after a site visit and drawings.

• Compact partial top-up or large dormer: $120,000 to $220,000, depending on structure and finishes.
• Full second-storey addition on a typical bungalow: $220,000 to $420,000 depending on square footage, insulation package, windows, and HVAC.
• Whole-home refresh pairing (main-floor updates, facade, roof): Add $40,000 to $150,000 depending on kitchens, baths, and exterior scope.

Typical inclusions: engineering, framing, roof, windows, insulation, siding, basic HVAC extension or new system, drywall, paint, standard flooring, and one new bathroom. Premium finishes and custom millwork increase cost.

Avoid these common mistakes

1. Designing a beautiful second floor, but forgetting where the stairs fit on the main floor.
2. Underestimating structural upgrades to the foundation and main level.
3. Skipping exterior insulation on the new level, which creates uneven comfort.
4. Choosing complex rooflines that add cost with little benefit.
5. Leaving HVAC sizing and zoning to the end instead of planning early.

How JG Contracting delivers smooth top-ups

• We start with a feasibility review and a clear scope with drawings and engineering.
• We schedule structure, cladding, windows, and mechanicals in the right order to keep the home weather-tight fast.
• We protect interiors below, manage dust, and keep neighbours informed.
• We finish with careful trim, paint, and a coordinated exterior so the addition feels original to the home.

Helpful companion reads on our site:

• Toronto Exterior Siding & Facade Upgrade Guide 2025
• Toronto Heat Pump & HVAC Retrofit Guide 2025
• Windows That Work in Toronto 2025
• Toronto Skylights Guide 2025

Ready to add the space you need? Contact us today to book a consultation. We will confirm feasibility, design a smart second floor, and provide a detailed quote and timeline.

📞 Call us at: 437-259-9632

✉️ Email us at: jgcontractingyyz@gmail.com

🌐 Website: https://jgcontractingyyz.com