What a multiplex is, and how it differs from a duplex, a townhouse and an apartment.

A multiplex in one sentence, and the words around it

A multiplex is a building on one residential lot that holds three or more separate homes, each with its own kitchen, bathroom and living space. The word comes from everyday speech, so its exact meaning depends on who writes it down. The City of Vancouver defines a multiplex, which it also calls a multiple dwelling, as 3 to 8 dwelling units across one or more buildings on a single site, each with its own direct exterior entrance. Burnaby's R1 district describes multiplexes as 3 to 6 homes in one building. Surrey uses its own word, houseplex, for a building of 3 or 4 principal homes that resembles a large house.

The shorter names count homes. A duplex has 2, a triplex 3, a fourplex 4 and a sixplex 6. A duplex falls below the 3-home starting point that Vancouver and Burnaby use for a multiplex. The counts line up with British Columbia's small-scale housing law, which requires cities to allow at least 3 homes on a lot of 280 square metres or less, 4 on a larger lot, and 6 on a lot of 281 square metres or more within 400 metres of a bus stop with a bus at least every 15 minutes on average, in the areas the law covers.

Those totals include secondary suites, garden suites, coach houses and laneway homes, because section 455 of the Local Government Act counts every self-contained home as a housing unit. A house with a suite and a laneway home is three housing units, the same count as a triplex. The suites chapter of this guide explains how each kind counts.

Vancouver's rules are under review. The City's multiplex page says staff are updating policies and regulations for multiplexes and other low-density housing, in response to Council motions in 2025 and 2026 and the province's Bill 25, with engagement from fall 2026 into early 2027 and a report to Council expected in early 2027.

Five ways to arrange the homes on a lot

The same number of homes can take different shapes. Side by side, each home runs from the ground to the roof and shares a wall with its neighbour. Stacked, one home sits above another, and the floor between them carries the fire and sound rating. Front and back, two buildings share the lot, one at the street and one at the rear. A houseplex, in Surrey's term, puts 3 or 4 homes inside the shape of one large house. A courtyard or cottage court places small detached homes around shared open space.

BC Assessment's use codes, listed in the province's policy manual, show the same shapes: duplexes side by side, front and back, and up and down, each in strata and non-strata versions, plus separate codes for triplexes and fourplexes. The forms chapter gives each shape with its bylaw definition and its effect on fire separation, exits and ownership.

The shape also decides what each home gets. A side-by-side home reaches the ground and can have its own door and yard. An upper home in a stacked building may need a second way out under Article 9.9.9.3 of the BC Building Code if it shares an exit stair. A rear building needs a route for fire department equipment from the street under Article 9.10.20.3.

The rules that shape the building

Part 9 of the BC Building Code 2024, the part for housing and small buildings, covers residential buildings of 3 storeys or less with a building area of 600 square metres or less. A larger building moves to Part 3. The province's policy manual says most small-scale multi-unit buildings will likely fall under Part 9. The City of Vancouver is the exception: BC Codes do not apply there, because the City has its own building bylaw.

Under Part 9, suites are separated by fire separations rated at least 45 minutes, and a home of 2 or more storeys by at least 1 hour. Each home must reach an ASTC rating of 47, or an STC rating of 50, against the spaces around it. STC and ASTC are measures of how much airborne sound a wall or floor blocks. Duplexes, triplexes, townhouses and row houses are exempt from the code's accessibility section, apart from one bathroom with walls reinforced for grab bars.

Energy rules apply as well. Steps 1 and 2 of the BC Energy Step Code for smaller buildings are now listed as Reserved and no longer meet the minimum, and since 10 March 2025 most new buildings must meet at least the first step of the Zero Carbon Step Code. The building code chapter sets out each rule with its article number.

How it compares, and what living in one involves

A multiplex sits between a house with a suite and an apartment building. A house with a suite is 2 homes on one title, and the suite cannot be strata titled on its own. A townhouse or row house lines homes up side by side, and Surrey's row housing building puts each home on its own lot. An apartment building is built around a common entrance and interior corridors, and above 3 storeys or 600 square metres of building area it falls under Part 3 of the code. The comparison chapter sets all four side by side in one table, with a section on Burnaby's duplex and multiplex rules.

Daily life in a multiplex involves shared walls and shared money. In a strata building, the strata corporation repairs common property under section 72 of the Strata Property Act, fees follow unit entitlement under section 99, and a buyer can ask for an Information Certificate under section 59. BC Hydro meters each home in a residential-only building separately. The living chapter covers parking, outdoor space and a checklist for buyers.

This guide explains what the buildings are. Three other guides on this site pick up the next questions: the multiplex design guide covers which type a lot can hold, the zoning guide covers the zone rules behind the unit counts, and the ownership guide covers strata, rental and partnership routes.