Why a Duplex Inspection Is Different

A duplex inspection costs more and takes longer than a single-family home inspection — and it should. You essentially have two complete homes to inspect, plus the shared structure, the separation between units, and the interconnected systems. A typical duplex inspection runs 3–4 hours and costs $550–$900 versus $400–$550 for a single-family home. Every dollar is worth it.

How to Find a Duplex-Experienced Inspector

Ask your real estate agent for referrals, but also interview the inspector yourself. Key question: 'How many multi-unit residential properties have you inspected in the past year?' and 'Are you familiar with Ontario Building Code requirements for fire separation in secondary units?' If they hesitate or give vague answers, find someone else. Organizations like OAHI (Ontario Association of Home Inspectors) can provide referrals to qualified inspectors.

What the Inspector Will Check (That's Unique to Duplexes)

Fire separation between units: the inspector will look at the separation wall and ceiling between units, checking for fire-rated drywall, proper caulking of any penetrations, and compliant door assemblies. This is the most critical duplex-specific item. Separate mechanical systems: ideally, each unit has its own furnace/HVAC, water heater, and electrical panel. Shared systems create coordination complexity between tenants and potential liability issues. Each unit's plumbing independence: can water be shut off to one unit without affecting the other?

Using the Report to Renegotiate

A thorough inspection report on an older Ontario duplex will typically identify $15,000–$50,000 in deficiencies. Don't panic — this is normal. The strategy: identify safety-critical items (fire separation deficiencies, electrical hazards, structural issues) and major system items (roof end-of-life, furnace needing replacement). Request a price reduction equal to the estimated cost of safety-critical repairs. Accept deferred maintenance items as known risk. Do not use every deficiency to renegotiate — sellers will push back, and you risk losing the deal over minor items when the fundamentals are sound.