Home › Services › Multi-Unit Inspection
Duplex · Triplex · Fourplex · Plexes and small income properties

Multi-unit inspection in
Montreal

Whether you are an owner-investor, buyer, seller, property manager, or preparing for major work, a plex inspection helps you better understand the apparent, visible and accessible condition of your residential plex (2 to 4 units — duplex, triplex, fourplex). Roof, foundation, visible structure, building envelope, exterior staircases, shared systems (plumbing, electrical, heating), access to units per agreement, and visible indications of wear or moisture are observed to provide a clear picture of the overall apparent condition of the building. The goal: identify items to monitor, prioritize necessary follow-ups, and help you make informed decisions before a purchase, a sale, major work or important maintenance. For 5+ unit multi-residential buildings, see our commercial / multi-unit inspection.

Content reviewed by Giacomo Ciavaglia · InterNACHI-certified building inspector

📞 (514) 802-7215 Book online →

InterNACHI Certified · Insured · 24h* Report

Scope of our multi-unit inspection The inspection is visual and non-invasive. It documents the visible and accessible condition of the building at the time of the visit, according to the agreement and available access. It does not replace engineering expertise, contractor estimates, environmental studies, real estate appraisal, financial analysis, legal advice or specialized regulatory verification.
What this page covers

Plexes and small income properties —
duplexes, triplexes and fourplexes.

This page covers inspection of residential plexes and small income properties of 2 to 4 units: duplexes, triplexes and fourplexes. Once a building has 5 or more units, the file is handled as commercial / multi-unit inspection because the scope, shared systems, access, risk profile and due-diligence level are different.

✓ Duplex (2 units) — residential / plex inspection on this page.
✓ Triplex (3 units) — residential / plex inspection on this page.
✓ Fourplex (4 units) — residential / plex inspection on this page.
✓ 5+ unit multi-residential buildings — handled as commercial / multi-unit inspection (different scope, systems, access and due diligence).

Note: this is our inspection-scope categorization. The legal, tax or municipal commercial/residential classification can depend on actual use, municipal zoning, the assessment roll, financing, insurance and the presence of mixed occupancy.

Better understand your plex

A multi-unit inspection for owners, investors and property managers

A plex inspection can be useful beyond buying or selling. It can help an owner-investor or property manager better understand the apparent, visible and accessible condition of the plex, plan major work (roof, foundation, exterior staircases, vertical plumbing, electrical, heating), prioritize long-term maintenance, or document visible warning signs such as moisture, cracks, water intrusion or deterioration.

Inspection scope: a plex inspection remains a visual building inspection of the property's apparent, visible and accessible condition. It does not replace financial analysis, lease review, legal advice, regulatory verification, or code-compliance certification.

Who this is for

A plex inspection
fits several profiles.

A plex inspection documents the apparent, visible and accessible condition of the residential plex (2 to 4 units) and its shared systems at the time of the visit. It serves anyone who wants to better understand the overall apparent condition of the building — whatever the context.

🏘️
Owner-investor
You own a plex (resident or rental) and want to better understand the apparent condition of the building, plan necessary follow-ups, and prioritize long-term maintenance.
For the owner-investor, the inspection provides a clear picture of the overall apparent condition of the building: roof, visible foundation, observable structure, exterior staircases, envelope, shared systems (plumbing, electrical, heating), units accessible per the agreement, and indications of wear or moisture. The report documents items to monitor with photos and priority levels, and points toward a recurring preventive inspection when relevant.
🔑
Plex buyer
You are evaluating a plex before purchase — to live in, partially rent out, or as an investment property. For the transaction context (inspection condition, short timelines, 24h report), see also our dedicated service.
For the plex buyer, see our dedicated service pre-purchase inspection, which covers short deadlines, reading the report for negotiation, and follow-up during the condition lift. The inspection documents the apparent condition of the building, units accessible per agreement, and observable shared systems. Inspection scope: it remains a visual building inspection — it does not replace financial analysis, lease review, legal advice, or specialized regulatory verification.
📋
Seller
You are preparing to list your plex. A prior inspection helps identify items to correct or disclose, and limits surprises during negotiation.
For the seller, see our dedicated service pre-sale inspection, structured specifically for listing preparation: prior picture of the building's apparent condition and accessible units, documentation useful for the seller's declaration, and support during negotiation with a potential buyer.
🛠️
Property manager or landlord
You manage a plex (as landlord or property manager) and want a clear picture of the building's apparent physical condition to better plan maintenance and anticipate work.
For the property manager or landlord, the inspection produces a structured picture of the building's overall apparent condition: roof, foundation, shared systems, exterior staircases, envelope, units accessible per agreement. The report documents items to monitor and orients long-term maintenance planning. See also our preventive inspection service for recurring follow-up.
🏗️
Before major work
You are planning major work (roof, foundation, exterior staircases, vertical plumbing, electrical, heating). The inspection establishes a prior picture of the visible components involved.
Before major work, the inspection documents the apparent condition of the components concerned and connected elements likely to be affected (shared systems, shared walls, unit access, visible structure). This helps better prepare contractor bids, sequence the work, and coordinate with tenants when access is needed. See also our preventive inspection service to plan longer-term maintenance.
📅
Tenant turnover or maintenance planning
You are taking advantage of a tenant turnover (unit accessible) to thoroughly examine a unit and shared systems observable from the unit, and plan follow-ups.
A tenant turnover gives free access to the unit, allowing a more complete reading of the apparent condition (finishes, visible plumbing, windows, balcony, signs of moisture or deterioration) and shared systems observable from the unit. The inspection documents these findings with photos and priority levels, and orients maintenance to plan. It remains a visual building inspection — it does not substitute for administrative or legal obligations related to a tenant turnover. See also preventive inspection.
Why inspect a multiplex

Evaluate your rental investment
with full clarity.

A revenue property is a major investment with elements to verify depending on age, maintenance history and available access. Shared systems, accessible units and visible components may influence planning after acquisition. Our inspection helps you get a clear picture of visible and accessible items before you buy. We inspect plexes across Montreal, Laval, the South Shore and the West Island. For commercial properties or 5+ unit multi-residential buildings, see our commercial / multi-unit inspection.

🏗
Each unit inspected
Each unit is verified separately: plumbing, electrical, heating, ventilation, windows and interior finishes.
Accessible units are reviewed visually according to the agreed scope. Differences between units, access limitations and visible conditions are documented clearly in the report.
⚡
Shared systems checked
Electrical panels, main plumbing, shared water heaters, central heating systems and service entrance evaluated in depth.
Shared plumbing, electrical distribution, heating, water entry, main drainage, roof and exterior components often carry the highest maintenance risk in a plex.
🔥
Fire safety
Verification of smoke detectors, emergency exits, fire separation between units and exterior staircases.
The inspection observes visible safety elements such as exits, stairs, guardrails, smoke alarms where accessible and apparent separation conditions. Formal code compliance is outside the visual inspection scope.
What we inspect

A complete inspection,
unit by unit.

Our multi-unit inspection is designed for revenue properties. We verify each unit and all shared systems to give you a faithful portrait of the building condition. Learn about mold risks specific to Montreal duplexes and moisture problems common in plex buildings.

✓Accessible units according to the agreement — Plumbing, electrical, heating, windows and finishes of units accessible at the time of the visit
✓Accessible common areas — Entrances, hallways, interior stairs and visible shared zones
✓Visible shared systems — Main panels, main piping, shared water heaters, observable service entrance
✓Visible roofing — Roofing, flashing, chimneys, roof access when safe
✓Accessible foundation and basement — Visible foundation walls, signs of cracks, apparent settlement, basement condition
✓Visible plumbing — Observable supply and drain piping, fixtures, accessible shut-off valves
✓Visible electrical — Accessible panels and sub-panels, observable wiring, apparent indicators
✓Visible heating and ventilation — Observable furnaces, baseboards, radiators, central boiler and thermostats
✓Visible stairs, balconies and guardrails — Interior and exterior stairs, guardrails, balconies, galleries
✓Drainage, moisture and maintenance priorities — Exterior drainage, signs of infiltration or moisture, summary of maintenance priorities
What every multiplex buyer should know

The challenges unique to
revenue properties.

A multiplex comes with issues you won't find in a single-family home. Here's what you need to understand before buying.

Shared systems A multiplex often has a single central heating system, a single water service entry, a single main drain and a single main electrical panel feeding sub-panels in each unit. A deficiency in a shared system may affect several units, so these elements are important to document.
Observable safety elements Multi-unit buildings have several observable safety elements: separation between units, smoke and CO detectors in each unit, emergency exits and exterior staircases. Apparent gaps may be documented in the report; specialist verification may be recommended when applicable.
Exterior staircases and balconies Montreal plexes are often equipped with metal or wood exterior staircases. These structures are exposed to freeze-thaw cycles and deteriorate over time. The visible condition of stairs, balconies and guardrails helps prioritize items to verify and work to plan.
Masonry and building envelope Many Montreal plexes have brick facades. Brick deteriorates over time: eroded mortar joints, cracked lintels, freeze-damaged bricks. The visible condition of masonry helps identify specialist verifications and maintenance priorities. Learn about moisture issues common in Montreal plexes.
Individual unit condition Each accessible unit can be in a different visible condition. A renovated unit does not mean the others are in the same condition. Units occupied by long-term tenants may limit visibility of plumbing, electrical or ventilation items.
Flat roof Most Montreal plexes have a flat roof with membrane. Membrane age, ponding water, drainage and past repairs are important visible indicators we document when accessible.
Our process

4 simple steps
to peace of mind.

1
Quote
Describe your building and we send you a detailed quote, typically within 24h.*
2
Coordination
We plan access to each unit with the seller, broker or tenants in place.
3
Inspection
Methodical inspection of each unit and all shared systems. Duration adapted to the number of units.
4
Report
Detailed report organized by unit with photos, priority findings and recommendations, delivered in 24 to 48 hours.*
Transparent pricing

Our multi-unit
inspection rates.

Every building is unique. The rate is custom-quoted based on the number of units, total area, building age and systems in place. Request your free quote.

🏠
Duplex
Inspection of both units, shared systems, structure, roof and all common elements. For condominiums, see also our common area inspection.
Custom quote
🏗
Triplex
Three units inspected individually, plus visible shared systems and observable fire-safety elements (smoke alarms, visible fire separation, exits — not a code-compliance certification).
Custom quote
🏢
Fourplex
Inspection of the 4 accessible units (fourplex) according to the agreement, with visible shared systems and observable safety elements. For 5+ unit multi-residential buildings, see our commercial / multi-unit inspection.
Custom quote
What sets us apart

Why choose
Inspecteur Élite.

✦ InterNACHI certified · IBC Network — Ongoing training and internationally recognized standards.
✦ FLIR thermal imaging available — Detection of infiltration between units, thermal bridges in exterior walls, and anomalies invisible to the naked eye. Available as an add-on.
✦ Report organized by unit — Each unit has its own section in the report. Clear, with photos and recommendations. Typically delivered in 24 to 48h.* *Depending on the number of units.
✦ Available 7 days a week — We work around your schedule and coordinate access with tenants.
✦ Thousands of inspections across Greater Montreal — Rosemont plexes, Villeray duplexes, Plateau triplexes, Verdun and Hochelaga revenue properties — we know the plexes here.
✦ Service available in English and French — Inspection and report in the language of your choice.
Decision support

Clear information to support
better planning.

For an investor, an inspection is not only about identifying visible deficiencies. It helps clarify maintenance priorities, observable risks, systems to monitor and specialist verifications that may influence planning after acquisition.

Client reviews

What our clients say

★★★★★
« Une excellente expérience! Giacomo est très professionnel et bien informé en matière de construction. Le rapport d'inspection fut produit rapidement et est très détaillé. »
Martyn Roy
Verified Google review
★★★★★
« Je suis très satisfait de l'inspection qui a été à mon bâtiment et le professionnalisme de l'inspecteur sur chaque petit détail. »
Roody Theodore
Verified Google review
★★★★★
« Il prend le temps de bien expliquer les choses et est très méticuleux. Son rapport est très détaillé et permet de prendre une décision éclairée. »
Fred Desautels
Verified Google review

Read all reviews →

FAQ

Learn more: see our guides on galvanized plumbing and cast iron drains, flat roofs and water infiltration. For a complete pillar guide, see our complete multi-unit inspection guide for Montreal.

Frequently asked questions about
multi-unit inspections.

Everything you need to know before booking your multiplex inspection in Montreal.

How does a duplex or triplex inspection work?+
Each accessible unit is examined individually according to the agreement: plumbing, electrical, heating, windows and visible finishes. Shared systems like the roof, foundation, structure and drainage are also observed. Duration varies based on the number of units and available access.
Do tenants need to be present or provide access?+
Access to each unit is necessary for a complete inspection. We recommend coordinating with the seller or broker to obtain tenant agreement and plan access in advance. If a unit is inaccessible, it will be excluded from the report.
How much does a multiplex inspection cost in Montreal?+
The price is custom-quoted based on the number of units, total area, building age and complexity. Every building is different — contact us for a free quote tailored to your situation. See our detailed pricing for context on residential services.
Are each unit's systems observed?+
We perform a visual review of accessible electrical, plumbing and safety-related installations in the units visited. Apparent anomalies and items requiring specialist review are identified in the report when applicable.
Can the inspection help me plan after purchase?+
The inspection identifies the visible condition of each accessible unit and items to expect in the short-to-medium term. This information helps clarify maintenance priorities and planning after acquisition.
Why do multiplex inspection prices vary?+
The price depends on the number of units, total area, building age and system complexity. A duplex takes less time than a five-unit building. Every inspection includes a basic FLIR thermal check (when conditions allow; advanced thermography available as add-on from $350+tax) and a comprehensive report organized by unit.
What does the report actually give me after the inspection?+
The report documents each accessible unit separately with photos, priority levels and recommendations. You see the observable condition of every unit, visible shared systems and maintenance priorities to plan for.
What happens if a unit is not accessible on inspection day?+
If a unit is not accessible, it will be excluded from the report and we will note it clearly. We recommend coordinating access in advance with the seller, broker or tenants. Ideally, all units should be accessible for a complete picture.
Are all units inspected?+
Units accessible at the time of the visit may be inspected depending on the agreement and available access. Access limitations are identified in the report.
Does the inspection cover shared systems?+
Visible and accessible shared systems may be observed, including plumbing, electrical, heating, ventilation, roofing, common areas and accessible exterior components.
Is this useful for a real estate investor?+
Yes. The inspection helps clarify the visible overall condition of the building, maintenance priorities, observable deficiencies and specialist verifications to consider.
What is the difference between duplex, triplex, fourplex, plex, multiplex, multi-family and income property?+
Duplex = 2 units. Triplex = 3 units. Fourplex or quadruplex = 4 units. Plex is a generic term for 2-4 units. Multiplex generally covers 4 to 12+ units. Multi-family and rental property refer to buildings primarily intended for rental. Income property is a financial term for buildings generating rental income. Above 5 units, the building falls under commercial multi-unit and requires an adapted inspection approach.
Why do 5+ unit buildings fall under the commercial category?+
In Quebec, buildings with 5 units or more are considered commercial multi-unit. Implications include: commercial building code (vs residential), enhanced fire egress and safety requirements, RBQ may require general contractor licence for major work, commercial bank financing (different rates and terms from residential), specific taxation. Our commercial multi-unit inspection documents specific compliance.
How long does a 4 to 12 unit plex inspection take?+
Duration scales with size: duplex/triplex: 3-4 hours, fourplex (4-plex): 4-5 hours, 5-8 units: 5-7 hours, 9-12 units: 6-8 hours, 13+ units: custom quote. Each accessible unit is individually inspected, plus common areas (exterior staircases, balconies, roofing, foundation, main plumbing, common electrical panel, common heating if applicable). Report within 24h* (or longer for large buildings).
What recurring findings do you see in Montreal plexes from 1900-1960?+
Montreal plexes from 1900-1960 (concentrated in the Plateau, Rosemont, Villeray, Verdun, Le Sud-Ouest, Mercier–Hochelaga) typically show: stone or unreinforced concrete foundations, galvanized and cast-iron plumbing, partially modernised electrical (sometimes residual knob-and-tube), multi-layer flat roofs, exterior wood or wrought-iron staircases, worn wood balconies, old timber-frame structure. These buildings often generate strong rental income but require gradual code upgrades (often 10-20% of purchase price over 5 years).
Do you inspect plex conversions to divided co-ownership?+
Yes. Converting a duplex/triplex/fourplex to divided co-ownership (each unit becomes a condo) is common in Montreal. Our inspection covers specific concerns: acoustic insulation between units (often insufficient for condo code), fire-rated separations between units, independent electrical per unit (separate meters), independent plumbing, compliance of maintenance log and contingency fund study (Law 16). Service offered in all sectors.
Is a plex inspection useful even if I am not buying?+
Yes. A plex inspection also serves the owner-investor or property manager who wants to better understand the apparent condition of the building, those preparing for major work, a seller preparing to list, or anyone who has noticed visible signs (moisture, cracks, water intrusion, deterioration). The inspection remains a visual building inspection — it does not replace financial analysis, lease review, or legal advice. For an active purchase, see also pre-purchase inspection; for a long-term owner, see also preventive inspection.
Should I inspect a plex before major work?+
Yes. Before major work (roof, foundation, exterior staircases, vertical plumbing, electrical, heating, full unit refit), an inspection documents the apparent, visible and accessible condition of the components concerned and connected elements likely to be affected (shared systems, shared walls, visible structure). This helps better prepare contractor bids, sequence the work, and coordinate with tenants when access is needed. See also our preventive inspection service for longer-term maintenance planning.
Is tenant turnover a good time to inspect a unit?+
Often yes. A tenant turnover gives free access to the unit, allowing a more complete reading of the apparent, visible and accessible condition: finishes, visible plumbing, windows and doors, balcony, ventilation, signs of moisture or deterioration, and shared systems observable from the unit. The inspection documents these findings with photos and priority levels, and orients maintenance to plan before re-leasing. It remains a visual building inspection — it does not substitute for administrative or legal obligations related to a tenant turnover.
Our other services

Related
services.

🏠
Pre-purchase inspection
Complete inspection for buying a single-family home in Montreal.
View service →
🏬
Commercial inspection
Inspection of commercial, industrial and mixed-use buildings, including 5+ unit multi-residential buildings.
View service →
🏢
Condo inspection
Specialized inspection for condo units in Montreal.
View service →
Common defects found during multi-unit inspection

Shared systems
to watch.

For a duplex, triplex or quadruplex, some shared components between units deserve special attention. A few topics documented on our blog:

🔧
Cast iron main drains
Shared evacuation plumbing — a drain at end of life affects every unit.
Read article →
🧱
Stone foundations
Older residential stock in Plateau / Villeray / Rosemont — structural particularities.
Read article →
🏠
Flat roofs
Shared roof — its condition affects every unit and impacts maintenance costs.
Read article →
💧
Humidity and mold
Often observed in shared basements and units with deficient ventilation.
Read article →
🌬️
Mold investigation
In-depth investigation available as a separate service if suspicion is confirmed.
View service →
📋
Hidden defects — buyer guide
Especially relevant for multi-unit where hidden defects affect rental income.
Read article →
★★★★★

" He inspected every unit individually and the report was organized perfectly. Essential for any plex buyer. "

Verified Client · South Shore

Sample report available

What your
report looks like.

Every inspection comes as a clear PDF report with photos, plain-language findings, and priority-ranked recommendations. View a representative sample to review the report format before booking.

View a sample report
Schedule your inspection

Ready to better understand
the apparent condition of your plex?

Every unit counts. Every system too. Schedule a plex inspection to help prioritize your decisions, follow-ups, or major planned work. Available 7 days a week. Report organized by unit. InterNACHI certified. IBC Network.
In an active purchase with a tight deadline? See also pre-purchase inspection or urgent home inspection (condition deadline).

📞 (514) 802-7215 Book my inspection →
✦ 5★ Google ✦ Thousands of inspections completed ✦ Certified and insured ✦ Detailed report within 24 to 48h*
📞 Call 💬 Text Book