BC Building Code 2024 for Multiplex
Everything you need to know about the 2024 BC Building Code as it applies to multiplex construction -- fire separation, accessibility, structural requirements, mechanical standards, and sound transmission.
Key Takeaways
- ✓ The 2024 code expands encapsulated mass timber construction (EMTC) to 18 storeys, up from 12. Light wood-frame remains the standard for Part 9 multiplexes (up to 4 storeys).
- ✓ Buildings with 3 or more dwelling units now require NFPA 13D sprinkler systems; duplexes (2 units) are generally exempt.
- ✓ EV charging readiness is now mandatory for 100% of parking stalls in new multiplex construction.
- ✓ All 10 BC standard designs are pre-compliant with the 2024 code, simplifying the building permit process.
What Changed in 2024?
The 2024 BC Building Code introduced several significant changes that directly affect multiplex construction. These updates align with BC's SSMUH legislation and the province's goals for housing density, energy efficiency, and accessibility.
Mass Timber Expansion
Encapsulated mass timber construction (EMTC) is now permitted up to 18 storeys for residential buildings, up from the previous 12-storey limit. Light wood-frame remains standard for Part 9 multiplexes up to 4 storeys.
Enhanced Sprinkler Requirements
Buildings with 3 or more dwelling units must now include NFPA 13D sprinkler systems. Duplexes (2 units) are generally exempt unless required by municipal bylaw.
EV Charging Infrastructure
100% of parking stalls in new multiplex construction must be EV-ready with conduit and electrical capacity.
Accessibility Upgrades
Minimum 20% of units must be adaptable, with barrier-free paths from parking to main entrances.
Fire Separation Requirements
Fire separation is one of the most critical building code requirements for multiplex construction. The rating depends on the building type and number of units. All shared walls, floors, and ceilings between dwelling units must achieve the minimum fire separation rating shown below.
| Fire Separation Rating | Fire Resistance Rating | Sprinkler Required | |
|---|---|---|---|
| Duplex (side-by-side) | 1 hour | 45 min | No (2 units) |
| Duplex (up-down) | 1 hour | 45 min | No (2 units) |
| Triplex | 1 hour | 45 min | Yes (NFPA 13D) |
| Fourplex | 1 hour | 1 hour | Yes (NFPA 13D) |
| Sixplex | 1.5 hour | 1 hour | Yes (NFPA 13D/13R) |
| ADU / Laneway | 1 hour (to principal) | 45 min | No (if <600 sqft) |
Fire-stopping is required at all penetrations through fire-rated assemblies (plumbing, electrical, HVAC).
Accessibility Requirements
The 2024 code strengthens accessibility requirements for multiplex housing, ensuring that new construction supports aging in place and serves residents with diverse mobility needs.
Barrier-Free Paths
At least one barrier-free path of travel must connect the public sidewalk, parking area, and main entrance of each ground-floor unit. This includes a maximum 1:20 slope for ramps (1:12 for short ramps), level landings at doors, and a minimum 1,100 mm clear width.
Adaptable Unit Requirements
A minimum of 20% of dwelling units (or all ground-floor units, whichever is greater) must be designed as adaptable units. This means wider doorways (minimum 810 mm clear), blocking in bathroom walls for future grab bars, and reinforced ceilings for ceiling lifts. Kitchens and bathrooms must allow wheelchair turning radius.
Universal Design Principles
While not strictly code-mandated, the BC standard designs incorporate universal design principles including lever-style door handles, rocker-style light switches, contrasting colour at stair nosings, and adequate lighting at all transition points. These features benefit all residents, not just those with mobility challenges.
Structural Requirements
BC's seismic zone designations and snow load requirements drive structural design for multiplex buildings. The 2024 code brings important updates for wood-frame and mass timber construction.
Wood Frame & Mass Timber
Light wood-frame construction remains the standard for Part 9 multiplexes up to 4 storeys. For larger projects, the 2024 code expands encapsulated mass timber construction (EMTC) to 18 storeys for residential buildings (previously 12). Mass timber must meet CAN/CSA O86 standards and requires a registered structural engineer's stamped drawings.
Foundation Requirements
All multiplex foundations must be designed for the specific site soil conditions based on a geotechnical report. In Metro Vancouver, this typically means concrete strip footings or mat slabs. Crawl spaces must have a minimum 600 mm clearance with vapour barriers. Screw pile foundations are acceptable for ADUs and laneway houses.
Seismic Design
Metro Vancouver is classified as a high seismic zone. All multiplex structures must comply with the National Building Code of Canada seismic provisions as adopted by BC. This includes shear wall design, hold-down connections, diaphragm detailing, and proper load path continuity from roof to foundation. Engineered floor and roof truss systems are standard.
Mechanical & Electrical
The 2024 code introduces stronger requirements for building systems, aligning with BC's electrification goals and preparing multiplex buildings for the future.
-
Separate Metering
Each dwelling unit must have its own electrical meter and panel. Gas metering (if applicable) must also be separate. This is essential for rental and strata-title configurations.
-
EV Charging Readiness
100% of parking stalls must have conduit and electrical panel capacity for Level 2 EV chargers. At least 20% must have chargers installed at occupancy. Electrical room sizing must account for future full EV load.
-
Heat Pump Standards
The 2024 code requires space heating from heat pumps or other electric sources for new construction. Gas furnaces are no longer permitted as the primary heating source. Air-source heat pumps should be sized and selected to meet the applicable Energy Step Code performance targets.
-
Ventilation
Each unit requires an HRV (heat recovery ventilator) or ERV (energy recovery ventilator) for continuous whole-house ventilation. Minimum 0.3 ACH continuous with boost capability to 0.5 ACH.
Sound Transmission Class (STC)
Noise transfer between units is a top concern for multiplex residents. The 2024 code requires a minimum STC 50 rating for all shared assemblies -- walls, floors, and ceilings between dwelling units.
Party Wall Assemblies
Double-stud walls with a minimum 25 mm air gap and batt insulation in both cavities reliably achieve STC 55-60. Resilient channels on one side add further decoupling. Avoid rigid connections (electrical boxes, plumbing) that bridge the air gap.
Floor/Ceiling Assemblies
Typical assemblies include engineered I-joists with batt insulation, resilient channels, and double layers of gypsum board on the ceiling side. Impact Insulation Class (IIC) of 50 is also recommended. Concrete toppings or gypcrete can significantly improve both STC and IIC performance.
Practical Tips
Stagger electrical outlets between units. Use acoustical sealant at all perimeter joints. Specify STC-rated doors for shared corridors. Consider upgraded underlayments (cork, recycled rubber) beneath hard flooring. An acoustical consultant can verify assemblies meet code during construction.
2024 vs Previous Code
A side-by-side comparison of key building code requirements showing what changed in the 2024 update for multiplex construction.
| Requirement | Previous Code | 2024 Code |
|---|---|---|
| Max mass timber (EMTC) | 12 storeys | 18 storeys (residential/office) |
| Sprinkler threshold | 4+ units or 3+ storeys | 3+ dwelling units (NFPA 13D) |
| EV charging readiness | Not required | 100% of parking stalls |
| Adaptable units | 10% of units | 20% minimum or ground floor |
| Minimum STC rating | STC 50 (party walls only) | STC 50 (all shared assemblies) |
| Energy Step Code baseline | Step 3 | Step 4 (standard designs) |
How Standard Designs Meet Code
All 10 BC standardized housing designs were developed in collaboration with building code officials and are pre-compliant with the 2024 BC Building Code. This means fire separation ratings, accessibility paths, structural connections, mechanical systems, and STC assemblies are already incorporated into the design concepts. When you start from a standard design, your architect adapts the concept to your lot -- but the fundamental code compliance work is already done. This reduces building permit review time and the risk of costly revisions.
Explore the full catalogue on our BC Standard Designs page.
Frequently Asked Questions
Do I need a sprinkler system for a duplex? +
What is the minimum fire separation between units? +
Are the BC standard designs already compliant with the 2024 code? +
Ready to Analyze Your Property?
Enter any BC address to get a free multiplex feasibility analysis with proforma projections.