What is the building envelope?
Building
envelope
Protect your structure. Maximize performance.
The building envelope is the protective shell of your home or building - the barrier that separates the indoor space from the elements outside. It includes everything from the foundation and exterior walls to the insulation, air and moisture barriers, windows, doors, flashing and siding.
In British Columbia coastal climate, where rain, wind, and temperature swings are common, a well-designed and properly installed building isn't just a luxury, - it's essential. It's what keeps water out, warmth in, and energy loss at the bay.
A high performance envelope reduces heating costs, prevent structural damage, and improves indoor air quality. Whether you're building new or upgrading an older structure, the envelope is your first and most important defense against long-term issues - and it starts with the right team
At Builderra, we specialize in building envelopes, that are designed to last - from blues skin, tyvek to z-girts, Cascadia clips and advanced flashing systems. With years of experience on BC jobs sites, we know what works in your climate and how to install right, the first time.
Built to code. Designed for BC.
At Builderra, all our building envelope installation are completed in full compliance with the BC building code (BCBC 2018, updated 2024) with special attention to part 9 (Housing and Small Buildings) and 5 (Environment Separation).
Air Barrier System (BCBC 9.25.3): We install continuous air barrier system to reduce uncontrolled air leakage, improving energy efficiency and indoor comfort.
Moisture Protection & Vapour Barriers (BCBC 9.25.4 and 9.25.1): We use proper sequencing of blue skin, Tyvek, insulation, ensuring water shedding and capillary break in line with best practices and code expectation.
Rain screen requirements (BCBC 9.27.2.2): Especially important in Vancouver and the Lower Mainland, where high rainfall demands a capillary break behind cladding. We use z-girts, H-tracks, pressure treated plywood strips (strapping) to meet or exceed rain screen requirements.
Flashing and water management (BCBC 9.27.3): We install flashing at all penetration and transition points, ensuring water is directed outwards - not trapped in the walls.
By staying code-compliant - and going beyond when needed - we ensure that your project passes inspection and performs for years to come. Our installations reflect not just what the code requires today, but what your building needs long-term in BC's wet, shifting climate.
Process and materials
Tyvek, VP, SIGA
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Tyvek house wrap applied as a reliable air and moisture barrier. Lightweight, tear-resistant, and proven over decades, Tyvek helps improve energy efficiency while preventing water intrusion behind siding.
VP membrane installed as vapour-permeable water resistant barrier. Ideal for rain screen systems, it allowed trapped moisture to escape while protecting wall assemblies from wind-driven rain - critical for BC's wet climate zones.
SIGA membrane installed for high- performance, airtight and weather-resistant envelope. Known for its superior adhesive technology and flexibility, SIGA supports Step Code compliance with airtight seals penetrations and complex transitions.
Flashing, Insulation, Rain screen
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Flashing installed at critical transition points - windows, doors, base of the walls, at floor line transitions, roof wall intersections, balcony or deck penetrations - to direct water away from the envelope. Proper flashing ensures drainage and prevent water ingress behind siding.
Rainscreen system installed to provide a drainage cavity between cladding and the weather barrier. Essential for BC building code compliance in wet zones, it helps moisture escape and protects the structure from long-term water damage.
Rigid Rockwool insulation installed as a part of the exterior wall system. Provides continuous thermal protection, moisture resistance and excellent fire performance - ideal for BC's rain screen assemblies.