External Insulation using ROCKWOOL with Brick Seismic Connections

Good morning to those who are online. We’ll wait a few more seconds for people to load up. We’ll be with you shortly. Welcome and greetings to everybody who has joined us from around the country. I hope the weather in your part of the world is cooperating. Thanks for joining us this morning. Today’s subject is brick seismic connections used in conjunction with external insulation and how these are used more commonly in commercial applications. My name is Mike Skilton, and I’m the General Manager of Outright Continuous Insulation. We thought today’s topic would be of interest, as brick has been used for many decades in various forms. More recently, manufacturers have upgraded their ranges, sizes, and colors, making brick a more attractive option for robust façade designs. We now see bricks being used in a wide range of buildings around the country, and we thought you would like to understand the options for building at a larger scale or in earthquake-prone areas. We’re fortunate to have some experienced speakers. First is Peter Raimondo, a building enclosure engineer and director of Oculus Architectural Engineering. Peter is a highly experienced façade engineer originally from Canada. He studied in Toronto, and for those who watch movies, we sometimes joke about calling him the man from Toronto. Peter has built a strong reputation for delivering robust and viable façade solutions around the country. With a career spanning numerous high-profile developments, he’s worked closely with architects, contractors, and consultants to integrate façade systems into overall building design. His strength lies in navigating key requirements, managing risk, and maintaining programs and budgets. Joining Peter today is my colleague Angela Duthie. Angela is our Technical Manager at Outright Continuous Insulation and a seasoned building product specialist with a decade of industry experience across many disciplines. She has developed a strong reputation for technical expertise and client support. She’s focused on the evolving demands of modern construction and is passionate about delivering quality products that support durability and sustainability while working collaboratively across the industry. We’ll move to our first poll: have you specified external wall insulation before? It’s great to see a high proportion of participants who have specified external insulation. It’s moving the dial from insulation models developed in the 60s and 70s in New Zealand. For those who haven’t used it yet, today should be informative and insightful. Angela will start by providing an overview of external insulation opportunities. She explains that MBIE made amendments in recent years around H1 energy efficiency; however, wall insulation requirements remained relatively untouched. If we simply increased wall thickness to 140 millimeters and added R3.5 lofted insulation in the cavity without considering air or vapor control or mechanical ventilation, it could potentially lead to future leaky building issues. Ubakus analysis shows condensation risk across different structure types. One example, sometimes referred to as the “wall of death,” demonstrates significant condensation risk because moisture hits a cold structure with no way to escape. This highlights the need to think holistically. Timber framing significantly reduces the performance of internal insulation, whereas external insulation acts like a coat wrapped around the entire building, minimizing or eliminating thermal bridges and delivering nearly 100 percent of the R-value. ROCKWOOL is manufactured from melted volcanic basalt rock. It’s melted down, spun like candy floss, and formed into slabs of various densities. It’s non-combustible and won’t burn up to 1,000 degrees Celsius, providing excellent fire design protection and protecting other combustible and structural materials on a project. ROCKWOOL also has strong acoustic properties, and STC and NRC values can be provided for both standalone products and assemblies. Being vapor open and water repellent means it won’t absorb or hold moisture, and its long-term performance remains unaffected if it gets wet. The higher density of ROCKWOOL provides rigidity and durability, making it well suited to external wall applications. ROCKWOOL rainscreen is a variant specifically designed for external insulation with enhanced water repellency and strong thermal performance. PIR is a closed-cell rigid polyisocyanurate insulation with a high-performance foam core and multi-layer aluminum foil facing on both sides. It delivers excellent thermal performance for its thickness and offers high compression strength of 175 kPa, making it suitable for warm roofs, external walls, and flooring. When installed correctly with fully taped joints, PIR is highly moisture resistant. Both PIR and ROCKWOOL can be used externally without requiring an additional building wrap over top. Angela also references Joe Lstiburek’s “perfect wall” concept, which ensures that control layers are continuous and positioned in the correct order of importance: rain, air, vapor, and thermal control. Nearly all claddings leak at some point, so the cavity and weather-resistive barrier provide the real protection. Air leakage can move significantly more moisture than vapor diffusion, making it more critical on the risk scale. Vapor control is climate-specific and must ensure that assemblies can dry appropriately. External insulation reduces internal temperature extremes, lowering condensation risk and extending the life of the structure and its components. Warm roofs and external insulation create comfortable living spaces while reducing heating and cooling demand. Peter then discusses seismic performance. He shows an image of damaged brick veneer following a seismic event, where cracks typically emanate from window corners due to stress concentration. While this may seem alarming, brick can accommodate seismic movement when properly detailed. Traditional strap ties are a single piece of metal fixed into the stud and embedded into the mortar joint. During seismic movement, the steel bends or dislodges to accommodate movement, which may not be the most durable or robust solution. In contrast, two-part brick ties consist of a thermal L-plate attached to the wall and a separate V-tie inserted into the bracket slot. The V-tie can slide back and forth, accommodating seismic movement without causing damage. The vertical slot allows for construction tolerance, while the horizontal sliding accommodates seismic movement. The system also incorporates insulation support tabs, eliminating the need for additional fixings such as stick pins or adhesives. Because timber studs are flexible and brick is rigid, the two-part tie allows the structure to move independently behind the brick without transferring excessive force into it. This system has been widely used in Canada and internationally and is increasingly being adopted in New Zealand. Project examples include Somerset St. John’s in Auckland, a five-story brick building incorporating ROCKWOOL external insulation and two-part ties. From the outside, it appears to be a typical brick building, but behind the façade sits a full layer of external insulation integrated with the tie system. Another example is the Hillmorton Hospital development in Christchurch, where ROCKWOOL board has been specified externally for an adult acute facility. The system enhances thermal performance, acoustic performance for sensitive occupants, and fire protection. The detailing includes brick, a 50-millimeter cavity, 50 millimeters of ROCKWOOL, and structural fixing with insulation support. A common rule of thumb places approximately 70 percent of the R-value externally and 30 percent internally unless hydrothermal modeling confirms an alternative configuration is appropriate. During the Q&A session, several topics are addressed. Using PIR externally can present vapor permeability considerations, but sufficient thickness and proper hydrothermal analysis mitigate condensation risks. The V-tie accommodates horizontal movement by sliding within the bracket slot. Typical cavity sizes range around 40 to 50 millimeters but can vary depending on engineering requirements. The system can be installed onto CLT panels with proper detailing and sufficient screw embedment. There is no strict height restriction for brick buildings, though taller buildings require careful detailing of movement and seismic joints. The system is generally straightforward to specify and achieve compliance with, particularly for low-rise projects, using standard spacings and detailing supported by engineering documentation. The session concludes with thanks to participants for their engagement and questions. Attendees are invited to participate in final polls and enter a draw for a building sciences event. The webinar will be made available online and posted to YouTube for those who wish to revisit it or share it with colleagues. On behalf of Peter, Angela, and Mike, the presenters thank everyone for attending and wish them well for the rest of the day.