Building Envelope Commissioning: The Missing Link for Future-Ready Buildings

Thursday, September 13, 8:30 – 9:30 AM

Global climate trends are clear: more extreme weather events, frequent and more intense rain events, and widely variable ambient temperatures. How do current building envelope design practices and retrofit strategies respond and how do we embed this future thinking into our projects?

Building Envelope Commissioning can provide the framework to facilitate conversations about ever-more-stringent standards, processes, codes, and performance requirements related to the building envelope. It also provides a process to ensure performance is embedded in project requirements and is delivered at each stage through construction completion.

This session will use project examples that demonstrate the application of commissioning principles on new construction, existing buildings, or individual enclosure elements – from below grade to the roof and beyond. We will discuss typical design-, tender-, and construction-phase practices that track and test enclosure performance while keeping project teams informed of how value engineering, change management, or substitutions may affect performance. Lastly, we will connect and compare these project examples to common industry guidelines and standards such as LEED v4, LEED EBOM, BOMA BEST, NIBS, ASHRAE, CSA, and ASTM to highlight the need for industry standardization.

Measured Drying Ability of Compact Low-Slope Roofs

Thursday, September 13, 9:30 – 10:30 AM

In conventional compact, low-slope roofs, insulation is sandwiched between two vapour-impermeable layers: on top, the roof membrane, and underneath, the concrete deck or metal deck (with an additional air- and vapour-retarding membrane). This approach can be problematic should water get into the roofing assembly—either during construction, due to a roofing membrane leak, or from air leakage from the interior.

RDH Building Science Laboratories recently completed Phase 1 of an experimental program involving three compact, low-slope roof assemblies on metal decks that were constructed side by side in a field exposure facility in Waterloo, Ontario (Climate Zone 5-6). One assembly was constructed as a reference or base case, with two vapour barriers. The two other assemblies were designed and constructed to allow drying by vapour diffusion, to either the top or bottom side. All three assemblies were subjected to periodic wetting by the injection of controlled amounts of water, and moisture movement was tracked using embedded moisture, temperature, and relative humidity sensors. It was found that the roof assembly with a high vapour permeance membrane on the metal deck (i.e., the inward drying assembly) was most effective in drying water following each intentional wetting. Implications for design and construction will be discussed.

Thermal Performance of Building Enclosures: Where, What, When, Who, How, and Why

Thursday, September 13, 11:00 – 12:00 Noon

Recent evolution of building codes across Canada has certainly raised awareness of effective thermal value for building enclosures, and accurately determining this value for various assemblies is becoming a hot topic. Thermal performance requirements in building codes are generally well defined, but the industry is still learning how best to incorporate these requirements into the design process. Ever-changing and increasingly stringent code requirements also mean the goal posts are not set: regular adaptation is required. This presentation will provide clarity on these issues by answering the following questions:

• WHERE in Canada are there established enclosure thermal performance requirements?
• WHAT standards and codes have been adopted in different Canadian jurisdictions?
• WHEN should effective thermal performance be introduced in the design process?
• WHO is responsible for confirming that the thermal design is code-compliant?
• HOW is compliance confirmed and documented? This will include discussion surrounding the available methods of determining effective thermal performance (i.e., 1-D calculations, 2-D and 3-D computer modelling, and physical testing) and their comparable levels of accuracy.
• WHY does all this even matter?

Roofing vs. Masonry – Who Wins?

Thursday, September 13, 1:30 – 2:30 PM

Historically, the performance of mass masonry wall construction relied on the ability of the system to absorb and release moisture through cyclical wetting and drying. In the era of mass masonry construction, the most prevalent roofing systems consisted of built-up, well-bonded, highly redundant membranes. Contemporary construction relies on a cohesive building envelope to provide a continuous barrier at both the roof and walls to prevent moisture and air infiltration to the interior. This evolution in construction methodology—a drive to “tighten-up” existing buildings—has resulted in challenging design, detailing, and construction approaches when reroofing existing historical buildings. Combining the skills, experience, and knowledge of roofers, masons, and design professionals into one team that is aware of the intended design goal supports the comprehensive development of effective, long-lasting details, and applicable installation and integration of roofing and masonry wall systems.

The authors will illustrate these themes with a discussion regarding design and installation of roofing systems on the back side of parapet walls and other masonry wall/roof interface issues. They will utilize case studies to provide examples of design and implementation challenges for new roofing systems and their interfaces with masonry walls. Challenges for reroofing include the integration of various roofing materials to provide a watertight system when installing to masonry and smooth-glazed terra cotta, and providing an integral water/air barrier when replacing an entire roof structure.

Liquid-Applied Air Barrier Systems for High-Rise Buildings: Code Requirements and Performance Testing

Thursday, September 13, 2:30 – 3:30 PM

Air barrier systems (ABS) are specified in Canadian codes to minimize the infiltration and exfiltration of air through the building envelope in order to control the risk of condensation. However, since the publication of the Energy Code of Canada in 2014, more attention has been drawn to the importance of an air barrier system to control the loss of energy. Recently, the Canadian Construction Material Centre (CCMC) developed performance criteria for liquid-applied ABS, including installation, barrier, and durability criteria. The CCMC is a recognized body that provides guidance to building officials with respect to the National Building Code of Canada (NBC) and the evaluation and testing of innovative products as alternative solutions meeting the requirements of the NBC. The performance criteria for an ABS will be of interest to air barrier material and air barrier system providers, architects, industry consultants, and contractors.

Design of Sloped Roofs in Snow Country

Thursday, September 13, 4:00 – 5:00 PM

The Canadian building codes provide requirements for the minimum structural standards to which roof assemblies in high snow load locations need to be designed. However, the building codes (Part 9 in particular) do not include specific requirements for design of these roofs for resistance to water ingress and resistance to damage caused by snow movement. Based on the number of failures the authors have reviewed, we suggest that design changes are required.

The presenter will discuss common problems caused by high snow loads, snow movement, air leakage, and the often-associated ice damming and water ingress. He will also discuss solutions that have been implemented. Comparison of monitoring results from a repaired and an unrepaired roof assembly (within the same residential complex) will be used to illustrate the importance of airtightness in reducing the temperature of roof assemblies and mitigating the resultant ice damming.

The presenter will also introduce the concept of “double-drained” sloped roof assemblies and discuss a case study where this approach has been successfully used to eliminate a systemic water-ingress problem at a high-end residential home located at a Canadian ski resort.

Whole-Building Airtightness Testing of Industrial, Commercial, and Institutional Buildings

Friday, September 14, 8:15 – 9:15 AM

This paper will address whole-building airtightness research carried out by the Building Envelope Technology Access Centre (BETAC) of Red River College, Winnipeg, Canada. Over the last five years, BETAC has tested over 50 large, commercial-style buildings ranging from 100-year-old churches to new schools. The goal of this work has been to establish baseline air leakage rates, and to compare pre- and post-retrofit airtightness rates to better understand the effectiveness of air leakage sealing in these types of buildings.

The results of this research were also used in the development of a new test procedure developed by the Air Barrier Association of America (ABAA). This led to the creation of ASTM WK35913 “Standard Test Method for Determining the Air Leakage Rate of Large or Multi-zone Buildings,” which introduced improvements from existing test methods to overcome restrictions on building height and climate conditions, and led to the creation of two distinct test procedures which focused on building durability and energy performance, respectively.

In Canada, building officials are starting to incorporate airtightness requirements into regional codes in locations such as Vancouver, Toronto and Manitoba. Also, the introduction of the National Master Specification on Building Enclosure Performance Testing and Commissioning now includes Whole-Building Airtightness Testing. This paper will conclude with a discussion of what the leakage rates should be for Canadian buildings.

Benefits of Dual-Barrier-Protected Membrane Roofs

Friday, September 14, 9:15 – 10:15 AM

Roofing membranes within a roof assembly are generally the only barrier to keep the elements out. Standard building cladding design recognizes that well-performing walls consist of layers of materials (zones) to resist wind, heat, rain, etc., to achieve the rainscreen principle in wall cladding. This dual-barrier design can be applied to roofs.

Protected membrane roof (PMR) assemblies can have superior performance over conventional roofs since the moisture-resistant insulation protects the primary roofing membrane from the environment. Dual-barrier design can be implemented to help reduce negative effects of water diffusing into the insulation or reducing the thermal performance by flowing underneath. Typical PMRs can be easily upgraded by the placement of a properly selected vapour-permeable drainage layer above the insulation.

In addition to reviewing the design considerations for a dual-barrier PMR, attributes of these systems will be reviewed, with case studies comparing PMRs to typical protected roofs.

Strategies for Effective Building Retrofits: Façade and Core

Friday, September 14, 10:45 – 11:45 PM

As buildings age, and standards for energy efficiency and carbon reduction increase, retrofit solutions must address both the skin and core of buildings. Façade retrofits (recladding or over-cladding) are often responses to deteriorating cladding elements, inefficient envelopes (thermal, moisture, etc.), aged materials, and/or aesthetic concerns. Recladding a building can increase thermal performance while increasing airtightness. Likewise, building core retrofits are responses to demands for more energy-efficient buildings with a lower carbon footprint.

The Roadmap to Retrofits in Canada (by CaGBC) provides recommended actions to achieve Canada’s net energy-reduction targets by 2030, two of which include recommissioning and deep retrofits. As consultants, we have the opportunity and responsibility to approach emission reduction and envelope performance as one.

The Hudson’s Bay Tower (401 Bay St.) and 120 & 130 Adelaide St. W. (Richmond Adelaide Centre) are examples of tower retrofit projects underway to improve building performance in conjunction with improvements to the buildings’ mechanical systems. Future recommissioning will give owners an opportunity to consider re-cladding along with core retrofits to achieve energy reduction targets.

Advanced planning, research, design, and coordination with all teams will achieve a well-performing whole building system – façade and core.

The Future of Building Envelope Inspections

Friday, September 14, 1:15 – 2:15 PM

The presentation will cover the use of unmanned aerial vehicles (UAVs) for building envelope applications and will focus on rotary vertical take-off and landing (VTOL) aircrafts. By gaining an appreciation of the benefits of deploying UAVs, stakeholders in the building envelope sector will have a better understanding of how this technology can be used to save time and money, and mitigate risk when executing visual inspections. The discussion will then move to cover common regulatory hurdles faced when implementing the technology for building envelope inspections and will be supported with case study examples. The current state of regulations governing the use of UAVs for commercial operations will be addressed, outlining the process for receiving the necessary Transport Canada approvals. There will be a brief examination of how regulations are expected to change by comparing the proposed Canadian framework to that which has recently been instituted in the United States. Next, the use of UAV data sets for reporting on the status of assets and structures will be conveyed by examining the different levels of processing. Finally, the presentation will shift to cover advancements in UAV hardware and software developments and how this will impact stakeholders in building envelope technologies and practices.

Humidity and Building Envelope Failure in Enclosed Swimming Pools, Hot Tubs, and Steam Rooms

Friday, September 14, 2:15 – 3:15 PM

High-humidity building enclosures are typically building occupancies where the relative humidity and temperature of indoor air are very high all year round. Building types that exhibit breaches in moisture-, air-, and vapour-control layers in enclosed spaces include: recreational centres, golf clubs, hospitals, hotels, extended care facilities, and rehab centres. Solutions for this building science problem are a topical area of interest as they are not related to mechanical systems.

In this presentation, IRC Building Sciences Group will present our experiences and client case studies focused on humidity and building envelope failure in enclosed spaces such as: swimming pools, hot tubs, and steam rooms. IRC will address their general building sciences findings and present solutions and examples for these types of high-humidity building enclosures that have their building envelope elements linked to exterior ambient conditions for all four seasons.

The challenge for building science engineers is to design for efficient moisture management and building envelope systems, especially for the ambient conditions prevalent during late fall, winter, and early spring seasons. IRC will cover their solutions implemented in the case studies for the following conditions: hot, moist air not adequately dissipating and causing condensation; external weather and internal humidity causing changing building conditions; and the presence of mould and excess moisture on wall systems causing rotting and extensive damage on interior finishes.

Canadian National Standard for the Vegetated Roof Assembly: Field Validation

Friday, September 14, 3:45 – 4:45 PM

The National Research Council of Canada (NRC), as part of a consortium with members from vegetated roof industries and roofing associations, established a national wind resistance standard for modular vegetated roof assemblies (MVRAs), named CAN/CSA A123.24-15, “Standard Test Method for Wind Resistance of Modular Vegetated Roof Assemblies.” Currently, this standard is widely used, on a voluntary basis, by the Canadian roofing industry for the wind performance compliance of MVRAs. The CAN/CSA A123.24-15 was developed based on the extensive data collected on various MVRAs by simulating wind in laboratory conditions.

The standard provides an experimental procedure to determine pass/fail criteria, as a consensus standard will do. From the wind resistance perspective, the standard evaluates the coherent wind performance of vegetated roof systems in regards to determining the uplift rating of MVRAs. CAN/CSA A123.24-15 is a valuable tool for both building officials and MVRA manufacturers to verify and demonstrate wind uplift compliance with the requirements of the building codes. This paper presents the details for CAN/CSA A123.24-15 implementation. It provides the fundamentals of MVRA wind performance, as well as the requirements, scope, and limitations of applying the CAN/CSA A123.24-15. In addition to laboratory results, a field data comparison will be presented as part of the validation process.