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The HPO is involved in a wide range of building science research projects. Browse through the list of projects that are completed or underway as well as project summaries and reports.

Performance Evaluation of Proprietary Drainage Components and Sheathing Membranes when Subjected to Climate Loads Summary Report

This project assessed wall performance with a variety of drainage components, evaluating how they compare to assemblies meeting National Building Code of Canada (NBC) requirements in different climates, including coastal areas. Funding was provided to the National Research Council of Canada (NRC) by BC Housing and other partners. For more information, the 10 study reports are posted on the Air Barrier Association of America website at:

Wetting and Drying Performance of Nail-Laminated Timber Assemblies

Full Report

Nail-laminated timber (NLT) is increasingly being used in wood construction, particularly in mid and high-rise wood construction. A research study was initiated in November 2014 to evaluate the wetting and drying performance of NLT, confirming without protection, rain water easily penetrates and gets trapped in NLT. Severe wetting leads to elevated moisture content, approaching or exceeding 30% in the core of a NLT member and may require months of drying time. The best practice is to avoid wetting. The report provides test results and describes various on-site protection measures. Contributing partners to this project include BC Housing and Natural Resources Canada (Canadian Forest Service). 

Guide for On-site Moisture Management of Wood Construction

Full Report

Moisture management during construction becomes more important as building size increases potentially prolonging exposure to inclement weather. In addition, drying capacities of some modern assemblies are reduced due increased insulation levels, and/or the use of membrane or insulation products with low vapour permeance. This new guide, developed by FPInnovations, addresses these issues providing useful information, such as moisture-related properties for several categories of wood materials/built-up assemblies, and related guidelines about on-site moisture management practices that adapt to suit a range of wood construction projects. Different levels and methods of protection strategies are provided based on durability risk. Contributing partners to this project include BC Housing, Natural Resources Canada and the Province of British Columbia. 

Vertical Movement Monitoring in Six-Storey Wood-Frame Building in British Columbia (BC)

Full Report

Vertical movement and wood moisture content were measured in a six-storey wood-frame residential building in the Lower Mainland of BC. The study generated a wealth of information consistent with results from previous monitoring studies on four-and five-storey buildings. The report provides results of measured movement over the entire building height recommending vertical movement estimate calculations taking in account both shrinkage and building load. To avoid potential adverse consequences due to variations and difficulty of accurately predicting building movement, add a good margin of safety in design. Contributing partners to this project include BC Housing and Natural Resources Canada (Canadian Forest Service). 

Insulated Concrete Form (ICF) Field Testing Report

Full Report

Overall, ICF wall assemblies are both water and airtight however, window-to-wall interfaces also tend to be the leakiest point in the system. In this study, ICF wall assembly details are developed, constructed and thermal performance evaluated through full-scale field testing. The aim of this study is to develop standard construction procedures with water and air penetration resistance levels comparable or better than conventional building systems. BC Ready-Mixed Concrete Association, BC Housing and a number of ICF product manufacturers collaborated on this research. 

Study of Airflow in Attic Space

Full Report

This research aims to establish relationships between attic ventilation rates and temperature and airflow distribution patterns in attics using Computational Fluid Dynamics (CFD) modelling with local climatic conditions. Four attic ventilation scenarios (i.e. sealed attic, buoyancy driven attic ventilation, and two buoyancy and wind driven attic ventilation cases) are examined under winter and summer weather conditions. The results show that attic ventilation in both cold and coastal climates is significantly affected by wind pressure and solar gain. Understanding airflow patterns and local temperature distributions in the attic space and roof structure is an essential step to help mitigate potential attic moisture problems. 

Greenhouse Gas Implications of HVAC Upgrades in Multi-Unit Residential Buildings 

Full Report

This research report explores approaches for reducing greenhouse gas (GHG) emissions through heating, ventilation, and air-conditioning upgrades in multi-unit residential building (MURBs) in British Columbia. As heating energy accounts for approximately 65% of the total energy consumption, focusing on improving energy efficiency for heating the building, fresh air and domestic hot water provides the most opportunity for reductions.  A checklist of different upgrade opportunities to consider is presented.

Properties and Position of Materials in the Building Envelope for Housing and Small Buildings 

Full Report

This research project conducted by the National Research Council of Canada’s (NRC) Construction group with funding support from the HPO and other industry partners looks at the risk of potential moisture problems associated with using outboard insulation products with varying levels of vapour permeability.  NRC undertook computer modelling of different wall systems in different Canadian climates incorporating outboard insulation of an R-4 or higher, with a water vapour permeance ranging from 2 to 1800 ng/(Pa•s•m²).  The results found that for all of the configurations studied the outboard insulation reduced the risk of condensation by increasing the wood sheathing temperature. 

International Window Standards

Full Report

A follow-up study to the Review of Window Energy Rating Procedure in Canada was undertaken to better understand how the rating system used in North America compared to Passive House and ISO fenestration energy rating systems used in Europe. The research identified that the performance measures in North America are more geared towards peak design conditions, whereas the European values are more average values suitable for annual energy simulations. The different calculations methods are leading North American window manufacturers to build narrower gaps between window panes than in Europe. The findings could help manufacturers to adapt their products for different jurisdictions.

Attic Ventilation and Moisture Research Study

Final Report

This report presents the findings of a two-phase research project that looked at the presence of moisture and mold growth on the roof sheathing of ventilated attics constructed in coastal climates. Phase 1 examined and confirmed through field testing and monitoring that in some maritime climates mold growth may occur even in well ventilated attics. Phase 2 of the study focused on evaluating the factors that lead to moisture collection and mold growth in order to identify design solutions and treatments that would minimize the potential for mold growth. 

Review of Window Energy Rating Procedure in Canada

Executive Summary 
Full Report

This study is a collaboration of industry and government representatives across Canada to determine if the Energy Rating (ER) in its current form is still appropriate for selecting energy efficient windows and doors for all areas within Canada. The ER, first introduced in 1989, is a Canadian energy efficiency metric defined in the CSA A440.2-09 Fenestration Energy Performance standard that evaluates energy performance. Since that time there have been a number of changes in the industry including house design and construction, advances in glass coating and window framing technology bringing to question the use of the Energy Rating.

Guide for Designing Energy-Efficient Building Enclosures  

View Guide

This new industry resource was developed by FPInnovations, in partnership with the Homeowner Protection Office, Canadian Wood Council and RDH Building Engineering. The Guide is intended to help architects, engineers, designers and builders improve the thermal performance of building enclosures of wood multi-unit residential buildings. It looks at design and construction best practices and material used to ensure durable performance. As a companion to the HPO’s Building Enclosure Design Guide, this Guide expands on the energy efficiency of building enclosures. 

ICF Wall Testing and Modeling - Lab Testing Report

Final Report

Phase 1 of this project identified that insulated concrete form (ICF) walls were found to be both water and airtight. However, conventional detailing of the window to wall interface was identified as a weak point in the system with respect to air and watertightness. The project pointed to the need to have new details developed that would reliably provide water and airtight tie-in between the window and the ICF concrete core. A total of six ICF wall assembly details were designed, constructed and tested as part of Phase 2 of the project. This report provides the findings of lab testing and thermal performance modeling of these assemblies. This study was co-funded by the BC Ready-Mixed Concrete Association (BCRMCA).

Universal Design Housing Pilot Project  

Funded by the HPO in partnership with the SAFERhome Standards Society and industry, this research project will gather data on the costs and benefits of incorporating universal design features into residential buildings. As well as providing insightful research results to share with industry, the project will inform developers of low-rise, multi-storey housing units and others about universal design standards to create homes that are safe, comfortable, convenient, and meet the changing lifestyle needs of homeowners. 

Energy Consumption and Conservation in Mid- and High-Rise Residential Buildings in British Columbia

Executive Summary
Full Report

The main objectives of this research were to review and assess the effects of building enclosure improvements on the space conditioning energy use in typical mid- and high-rise multi-unit residential buildings in the Lower Mainland of British Columbia and Victoria, and to develop better strategies that take into account enclosure repairs, energy conservation and greenhouse gas emissions. Contributing partners to this project include: CMHC, HPO,
BC Hydro, Fortis BC, City of Vancouver and RDH Building Engineering.

Wind-driven Rain Study in the Coastal Climate of British Columbia

Full Report

The objectives of this study were to quantify the amount of rain impinged on typical building wall surfaces, establish the influence of overhang on wind-driven rain exposure, and verify the empirical method of quantifying wind-driven rain based on comparisons to new measurements at various locations in Metro Vancouver. Buildings with sloped and flat roofs, with and without roof overhangs were included for comparative purposes. Parameters monitored include local weather data (i.e. wind speed, wind direction and horizontal rainfall), and driving rain on the façade. This research was co-funded by the HPO, CMHC and BC Housing.

Field Investigations on the Application of ACQ Treated Wood and Use of Metal Fasteners and Connectors in Residential Construction

Full Report

Chromated Copper Arsenate (CCA) treated lumber has been phased out for most exterior residential applications and is being replaced with Alkaline Copper Quaternary (ACQ). The copper levels in the ACQ treated wood are significantly greater than in the CCA treated wood, which increases the risk of galvanic corrosion on metal fasteners, connectors and anchors. Manufacturer guidelines and related literature suggest appropriate metal hardware be used with ACQ treated wood. A field survey was carried out at a sample of building sites in the Lower Mainland region to determine whether compatible metal components are specified and used, and whether there is an indication of premature corrosion of metal components. Research partners include HPO and the Technical Research Committee of the Canadian Home Builders Association of BC who assisted in identifying builders to participate in the field survey.

Performance Monitoring of Rainscreen Wall Assemblies in Vancouver British Columbia

Final report

This project involves measuring and monitoring the performance of rainscreen wall assemblies within new and rehabilitated low, mid and high-rise residential buildings. A total of five buildings in Vancouver, British Columbia were studied. Related measurements (e.g., temperature, wood moisture content, relative humidity, local weather conditions including rainfall, driving rainfall and pressure differences across the walls) were collected and analyzed to assess the effectiveness of rainscreen wall assemblies. This research was co-funded by the HPO, CMHC and BC Housing.

Study of High-Rise Envelope Performance in the Coastal Climate of British Columbia

Full report

This research project identifies factors contributing to envelope performance problems and successes in non-combustible high-rise residential buildings. The study correlates building envelope performance with sources of moisture, such as design features, construction of assemblies, and details. Key factors for successful design and construction of the building envelope assemblies and details are identified in this report. The HPO and CMHC are the primary sponsors for this research project.

Study of Poured-In-Place Concrete Wall Assemblies in Coastal B.C.

CMHC Research Highlight

Rainscreen wall and window assemblies are now being used in coastal British Columbia multi-unit residential construction because they provide improved water penetration control properties and acceptable long-term performance. Builders and the design community have been increasingly utilizing poured-in-place concrete wall assemblies in combination with rainscreen windows to provide acceptable long-term envelope performance. In order to continue building confidently with this form of construction, Canada Mortgage and Housing Corporation (CMHC) and the Homeowner Protection Office commissioned a study to analyze and document potential performance questions associated with poured in-place concrete wall assemblies, as well as to develop a guideline for appropriate design and construction practices.

Contact the HPO to receive a copy of this report on CD.

Earthquake Testing of Rainscreen Stucco Systems for B.C. Residential Wood-Frame Construction

This project looks at the performance of stucco wall assemblies in an earthquake situation. The research compares the earthquake performance of rainscreen and non-rainscreen stucco systems, through which refinements to the design of rainscreen stucco systems have been developed to improve earthquake performance. The research was conducted at the University of British Columbia seismic research facility using test wall panels as well as dynamic tests of a two-storey house with stucco cladding. Partners for this project include HPO, CMHC and BC Housing.

Videos demonstrating the seismic tests are available as part of this study. Contact the HPO to receive a CD containing the reports and videos. 

Envelope Drying Rates Analysis

Full report

A Building Envelope Research Consortium (BERC) study of drying rates of various wall assemblies under controlled laboratory conditions.