Big White Step Code & AeroBarrier Air Sealing

Current Step: 3 | ACH Target: 2.5 ACH50 | Climate Zone: 7 | Permit Office: RDCO Building Services

The Most Demanding Climate Zone in the Region

Big White sits at approximately 1,755 metres elevation, placing it squarely in Climate Zone 7, the most demanding climate zone that BC residential builders typically encounter. With extreme cold, heavy snowpack, and a heating season that stretches well into spring, every detail of the building envelope matters.

The Regional District of Central Okanagan (RDCO) administers building permits for Big White. Builders working on the mountain need to meet Step 3 requirements with an energy model calibrated to CZ7 weather data, which produces significantly different results than the CZ5 data used just 45 minutes down the highway in Kelowna.

Current Step Code Requirements

Step 3 compliance is required for all new Part 9 residential construction at Big White. The ACH target is 2.5 ACH50, confirmed through a blower door test conducted before occupancy.

Climate Zone 7 impacts every component of the energy model:

• Wall assemblies typically need R-28 or higher effective values
• Ceiling insulation requirements push well above R-60
• Foundation insulation becomes critical with sustained below-zero ground temperatures
• Windows should be triple-pane with low U-values, especially on exposed elevations
• Air tightness carries an outsized energy impact; every 0.5 ACH50 reduction produces measurable savings

Resort Construction Challenges

Big White’s building stock consists primarily of ski chalets, duplexes, townhomes, and small multi-unit buildings. These resort-style buildings present unique air sealing challenges:

• Shared wall assemblies between units that need fire-rated and air-sealed detailing
• Steep roof pitches and dormers with complex framing intersections
• Hot tub and spa penetrations through exterior walls
• Boot rooms and ski storage below heated living areas
• Large window walls facing ski runs, creating extensive rough-opening perimeters
• Elevated decks and cantilevered balconies that interrupt the thermal envelope

Traditional air sealing methods struggle to address all of these simultaneously, especially when construction schedules are compressed to fit between ski seasons.

Why AeroBarrier Makes Sense at Big White

AeroBarrier is particularly well-suited to Big White construction. The aerosolized sealant is applied indoors after rough-in work and before drywall, pressurizing the home while sealing leaks in real time. Builders see their ACH50 number drop on a live display as the application proceeds.

Key advantages for Big White projects:

• Seals complex geometry including vaulted ceilings, dormers, and shared walls
• Real-time ACH50 monitoring confirms compliance before you close up walls
• Consistent performance across varying crew skill levels and tight mountain schedules
• Single-day process minimizes time on the mountain during construction
• Works in any weather since it’s applied indoors at controlled temperatures

Okanagan AeroBarrier Inc. is based in the Okanagan and serves Big White regularly. The mountain is less than an hour from our base, making scheduling efficient for builders with active projects.

FortisBC Rebates and Incentives

Big White falls within FortisBC service territory. Builders and homeowners constructing new homes can access FortisBC rebates for high-performance construction. Given how demanding the CZ7 energy model is, every performance dollar counts.

Use our rebate calculator to estimate what’s available for your Big White project.

ACH Targets in Extreme Cold

The 2.5 ACH50 target takes on heightened importance at Big White. In CZ7, the energy penalty for air leakage is roughly 40% greater than in CZ5. A home leaking at 3.5 ACH50 in Kelowna wastes energy; the same home at Big White wastes significantly more.

Some builders at Big White are already targeting Step 4 performance levels (1.5 ACH50) to future-proof their builds and maximize the long-term value of resort properties.

Planning Your Big White Build

If you’re adapting plans from a valley project, work with your energy advisor before committing to a design. The CZ7 energy model will likely require:

• Thicker wall assemblies or exterior insulation strategies
• Upgraded mechanical systems sized for extreme cold
• A deliberate air barrier strategy, not an afterthought

Getting the air barrier right from the start avoids the cost and delay of failing a blower door test at elevation, where rescheduling trades is more difficult than in the valley.

Frequently Asked Questions

Does RDCO require Step Code compliance for Big White builds?

Yes. The RDCO requires Step 3 for Part 9 residential buildings, which includes Big White. The energy model must use CZ7 weather data appropriate for the elevation and location.

How does altitude affect blower door testing?

Blower door equipment is calibrated to account for air density differences at elevation. A certified tester will adjust their readings accordingly. The 2.5 ACH50 target remains the same regardless of altitude.

Is AeroBarrier available for townhome and duplex projects?

Absolutely. AeroBarrier works on multi-unit projects by sealing each unit individually. Shared walls, party walls, and fire separations all benefit from the comprehensive sealing that AeroBarrier provides.

What’s the difference between building at Big White vs. Kelowna?

The biggest difference is the climate zone. Big White is CZ7 while Kelowna is CZ5. This means higher insulation requirements, more demanding energy model results, and a greater energy penalty for any air leakage. The same house plan will need a better envelope at Big White.

Can I build to Step 4 at Big White?

Yes, though it requires careful planning. The 1.5 ACH50 target is achievable with AeroBarrier, but the rest of the energy model (insulation, windows, mechanicals) needs to be designed for CZ7 Step 4 from the start. See our Step 4 guide for details.

How do I get a quote for a Big White project?

Call us at 250-864-8727 or get a free consultation. We’ll need your floor plans, target ACH50, and approximate timeline. Okanagan AeroBarrier Inc. — hello@okaerobarrier.com

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Ready to hit your ACH target at Big White? Call us at 250-864-8727 or get a free consultation. Okanagan AeroBarrier Inc. — hello@okaerobarrier.com