Cost to rebuild 2 car detached garage on existing slab foundation?

Rebuilding a detached 2-car garage on an existing slab in Metro Vancouver typically runs $60,000–$120,000+, depending on size, finishes, and municipality.

The good news is that reusing your existing slab eliminates one of the most expensive parts of a garage build — excavation and concrete work can easily add $15,000–$25,000 to a new build. That said, the slab will need to be inspected first to confirm it's structurally sound, properly sized, and meets current code requirements before a building department will accept it as the foundation for a new structure.

Typical Cost Ranges (Metro Vancouver 2025)

Here's how the numbers generally break down for a standard 20x22 ft (440 sq ft) to 24x24 ft (576 sq ft) detached garage:

• Basic/functional build — $60,000–$80,000: Standard framing, OSB sheathing, vinyl or T1-11 siding, asphalt shingles, single roll-up door per stall, basic electrical (outlets, lighting, panel sub-feed)
• Mid-range — $80,000–$100,000: Hardie board or cedar siding, insulated walls and ceiling, insulated garage doors with openers, upgraded electrical, drywalled interior, man door
• Premium/finished — $100,000–$120,000+: Full interior finish, epoxy floor coating, EV charger rough-in, workshop wiring, custom doors, storage systems, possibly a loft or bonus room above

Key cost drivers include the height of the structure (a single-storey vs. a garage with a loft or carriage house above is a completely different budget), the roofline complexity, exterior cladding choice, and whether you're adding heating or a bathroom.

Vancouver-Specific Considerations

A building permit is required — no exceptions. Permit fees typically run $1,500–$4,000+ depending on your municipality and the declared construction value. In the City of Vancouver, expect 4–8 weeks for permit approval; suburban municipalities like Surrey, Coquitlam, or Langley are often faster. Your existing slab will need to meet current BCBC 2024 requirements, including updated seismic bracing provisions (Section 9.23) that took effect March 10, 2025 — your structural framing plan needs to reflect this.

If your property is in the City of Vancouver and you're considering adding a suite above the garage (a carriage house), that triggers BC Housing's Licensed Residential Builder requirement and 2-5-10 home warranty insurance — budget an additional $10,000–$20,000 for warranty and added code compliance. For a straight garage rebuild with no dwelling unit, a standard residential contractor is fine, but confirm they carry WorkSafeBC coverage and $2M+ general liability insurance.

Also worth noting: if your municipality requires sewer separation as part of the permit (common in older Metro Vancouver neighbourhoods), budget an additional $5,000–$15,000 for that work.

When to Get a Structural Engineer Involved

Before framing goes up, have a structural engineer or your contractor assess the existing slab — check for cracking, heaving, adequate thickness (minimum 4 inches, ideally 4–6 inches reinforced), and proper drainage slope. If the slab is undersized or deteriorating, a partial or full replacement may be necessary, which changes your budget significantly. An engineer's letter confirming slab adequacy will also smooth the permit process considerably.

Next Steps

Get 2–3 quotes from licensed contractors who pull their own permits — any contractor asking you to handle permits yourself is a red flag. Bring your lot dimensions, existing slab measurements, and any drawings you have to those conversations. You can also find qualified local contractors in the Vancouver Construction Network directory at vancouverconstructionnetwork.com/directory to start comparing.