Building a triple-container modular home in Ottawa requires specific attention to the Ontario Building Code (OBC), particularly regarding frost protection and thermal performance in Climate Zone 6.
A "floating pad" (slab-on-grade) is generally only permitted for accessory structures like garages or sheds. For a permanent residence in Ottawa, the OBC typically requires foundations to extend below the frost line (approx. 4 feet). To use a slab-on-grade for a home, you must build a Frost-Protected Shallow Foundation (FPSF), which uses rigid insulation to trap geothermal heat and prevent the ground beneath the slab from freezing.
Phase 1: Project Plan & Permitting
Engineering & Design (Months 1-2): Hire a structural engineer to certify the container modifications (cutting steel for the 20' spans) and design the FPSF slab.
Permit Submission (Month 3): Submit plans to the City of Ottawa. You will need a site plan, architectural drawings (provided in your images), and a mechanical/ventilation design (OBC requires an HRV - Heat Recovery Ventilator).
Site Prep & Slab (Month 4): Excavate topsoil, lay 6-12" of compacted Granular A, install vertical and horizontal XPS insulation (R-10 to R-20), and pour the reinforced 32 MPa concrete slab with radiant heating loops if desired.
Container Placement & Steel Work (Month 5): Crane the three units onto the slab. Weld the "Reinforced Structural Openings" as noted in your plans using C-channel or RHS steel beams.
Roofing & Envelope (Month 6): Construct the engineered gable roof system. Use hurricane ties and weldable base plates to secure the wooden trusses to the steel containers.
Insulation & Systems (Months 7-8): Apply closed-cell spray foam (minimum R-24 for walls, R-50+ for ceilings). Install electrical, plumbing, and the HRV system.
Finishing (Months 9-10): Install the cedar plank deck, interior drywall, and exterior siding.
Materials List
Category Item Description
Structure 3x 40' High Cube Shipping Containers (9.5' H); Structural Steel (C-channel/I-beams) for spans.
Foundation 32 MPa Concrete; Rebar (#4 or #5); 2" to 4" Rigid XPS Insulation (Type IV); Compacted Granular A.
Roofing Pre-engineered Wood Trusses; 5/8" OSB Sheathing; Standing Seam Metal Roofing; Ice & Water Shield.
Insulation Closed-cell Spray Foam (2lb density); 6-mil Polyethylene Vapor Barrier (for floor/ceiling).
Exterior Cedar Planks (Decking); Pressure-treated 2x8 joists (Deck Frame); Helical Piles (for Deck support).
Windows/Doors Argon-filled Double or Triple Pane Glazing (Low-E coating) to meet OBC SB-12 energy standards.
Mechanical Heat Recovery Ventilator (HRV); Air-Source Heat Pump (Mini-split); PEX Piping.
Critical Code Compliance Notes
Thermal Bridging: Steel is highly conductive. You must apply continuous insulation on either the exterior or interior to prevent "ghosting" (condensation lines) on your walls.
Ceiling Height: Your plan shows a 9.5' High Cube. After floor and ceiling insulation, ensure you maintain the minimum OBC requirement of 2300 mm (approx 7' 6") for at least 75% of the living area.
Egress: Ensure the windows in Bedroom 2 and the Master satisfy the "Emergency Escape" size requirements (minimum 0.35 m^2 with no dimension less than 380 mm).
Decking: In Ottawa, any deck higher than 24" off the ground requires a guardrail (36" to 42" high) with no openings larger than 4" (100 mm).
