Commercial Air Sealing for Part 3 Buildings in BC

Commercial and multi-unit residential buildings in British Columbia fall under Part 3 of the BC Building Code. Part 3 buildings face their own air barrier performance requirements that grow stricter every code cycle. Whether you are delivering a mixed-use building in the Okanagan, a six-storey wood frame in the Interior, or an institutional renovation that has to hit aggressive energy targets, air leakage is the first metric that makes or breaks your compliance story.

Okanagan AeroBarrier Inc. delivers AeroBarrier aerosol air sealing for Part 3 projects across the BC Interior. The same technology we use on 100+ residential homes scales to commercial applications without losing the precision that makes it work.

Part 3 vs Part 9 - Why Commercial Is Different

Part 9 residential buildings (single-family homes, small multi-unit up to three storeys) operate under the BC Energy Step Code airtightness targets measured in ACH50 - air changes per hour at 50 pascals. Part 3 buildings (larger multi-unit, commercial, institutional) operate under a different framework. Instead of ACH50, Part 3 airtightness is typically measured in liters per second per square meter of envelope area (L/s/m²).

The physics are the same. Air leaks cost energy, damage envelopes, and hurt occupant comfort. But the numbers look different, the testing equipment is different, and the air barrier strategies have to scale to much larger envelope areas. A single-family home might have 300 square meters of envelope. A six-storey multi-unit residential building can easily exceed 5,000 square meters. The details that worked for the house do not automatically scale.

Multi-Unit Residential Projects

Multi-unit residential (MURB) construction is where we see the most Part 3 air sealing demand in the Interior. These projects include:

• Six-storey wood frame apartments (Part 3 under BC Building Code)
• Townhouse and row house developments with shared party walls
• Mixed-use buildings with ground-floor commercial and residential above
• Condo and rental developments subject to BC Building Code Part 3 Section 9.36 or Step Code equivalents

For MURBs, air sealing affects more than energy. Compartmentalization between units is a life-safety requirement. Air leaks that bridge suites can spread smoke, odors, and noise - issues that haunt building operators for decades after occupancy. AeroBarrier seals these transitions reliably, so each suite is properly compartmentalized from its neighbors.

Office and Commercial Buildings

Commercial office and retail projects face their own air sealing pressures. Tenant comfort, HVAC efficiency, and energy code compliance all depend on a continuous air barrier. The challenge with commercial buildings is that the envelope assemblies are often non-standard - curtain wall sections, large overhead doors, loading dock transitions, and complex mechanical penetrations. Traditional air sealing struggles to cover all of these with consistent quality.

AeroBarrier finds and seals leaks automatically. The aerosol sealant does not care whether the gap is behind a curtain wall mullion or in a rim joist - it goes where the air is escaping and closes the leak.

Institutional Buildings

Schools, healthcare facilities, community centers, and municipal buildings in BC increasingly face aggressive energy targets driven by CleanBC and provincial climate commitments. Institutional projects often target Passive House, LEED Platinum, or Zero Carbon Building Standard certifications. Every one of these frameworks rewards tight envelopes.

We have supported institutional projects where the air barrier performance target would be impossible to reach with traditional detailing alone. AeroBarrier adds the margin that makes aggressive targets achievable in real-world construction.

The Commercial AeroBarrier Process

For Part 3 projects, we scale the same core AeroBarrier process used in residential work. The key differences are:

1. Compartmentalized sealing - we seal each suite or zone individually, so testing and verification happen per unit
2. Multiple blower door setup - larger zones may need multiple blowers to achieve pressurization
3. Extended scheduling - commercial projects take more days on site than single-family homes
4. Documentation per zone - we report airtightness results for every sealed area, supporting your compliance submissions

The aerosol sealant itself is the same water-based, non-toxic material we use on residential projects. It does not off-gas VOCs, it does not leave residue on finished surfaces, and it does not interfere with interior trades that follow.

Working With Your Project Team

For commercial air sealing to succeed, we work closely with:

• Architects and envelope consultants on air barrier strategy and continuity
• General contractors on scheduling and trade sequencing
• Commissioning agents on verification and documentation
• Energy modelers on compliance reporting

Early engagement is critical. Commercial air sealing works best when the design accommodates the application process and the schedule includes the required sealing window. Bringing us in after drywall and finishes are complete limits what AeroBarrier can accomplish.

Results You Can Expect

Our residential track record includes 100+ verified seals and a best result of 0.24 ACH50 - well below Passive House requirements. Commercial projects target different metrics, but the underlying performance is the same. We consistently deliver airtightness that exceeds code minimums and supports the most aggressive energy targets in the market.

Service Area

We deliver commercial air sealing across the BC Interior including Kelowna, Kamloops, Vernon, Penticton, West Kelowna, Salmon Arm, and surrounding regions.

Frequently Asked Questions

Does AeroBarrier work on larger commercial envelopes?

Yes. The technology scales by compartmentalizing the work into zones. Each zone is sealed and tested independently, with results documented for your compliance package.

How does commercial AeroBarrier pricing compare to residential?

Commercial pricing is quoted per project based on envelope area, number of zones, schedule, and target performance. It is not a flat per-square-foot number. Call us at 250-864-8727 with your project details for a quote.

Can AeroBarrier be applied after drywall is up?

The ideal window is at rough-in before drywall. Post-drywall application is possible in some cases but less effective than pre-drywall. We will assess your project specifics and advise.

Is the sealant safe for occupied spaces?

The sealant is water-based, non-toxic, and GREENGUARD Gold certified. It is safe around interior trades and does not leave residue on finished surfaces. Spaces can be re-occupied quickly after application.

Do commercial projects qualify for rebates?

Commercial rebate programs differ from residential. BC Hydro and FortisBC offer commercial new construction incentives that may apply depending on your project's energy performance. We can point you to the current programs during scoping.