H ealthy High-rise A Guide to Innovation in the Design and Construction of High-Rise Residential Buildings CMHC—Home to Canadians Canada Mortgage and Housing Corporation (CMHC) is the Government of Canada’s national housing agency.We help Canadians gain access to a wide choice of quality, affordable homes. Our mortgage loan insurance program has helped many Canadians realize their dream of owning a home.We provide financial assistance to help Canadians most in need to gain access to safe, affordable housing.Through our research, we encourage innovation in housing design and technology, community planning, housing choice and finance.We also work in partnership with industry and other Team Canada members to sell Canadian products and expertise in foreign markets, thereby creating jobs for Canadians here at home. 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If you wish to obtain this publication in alternative formats, call 1 800 668-2642. Healthy High-Rise A Guide to Innovation in the Design and Construction of High-Rise Residential Buildings Canada Mortgage and Housing Corporation Prepared by: The Sheltair Group Société Logique Inc. Paul Kernan, architect An update of the “IDEAS Challenge Better Buildings - A Guide to Innovation in the Design and Construction of High-Rise Residential Buildings” CMHC offers a wide range of housing-related information. For details, call 1 800 668-2642 or visit our home page at www.cmhc-schl.gc.ca Cette publication est aussi disponible en français sous le titre: Guide de conception des tours d'habitation saines, 62806 The information contained in this publication represents current research results available to CMHC, and has been reviewed by a wide spectrum of experts in the housing industry. Readers are advised to evaluate the information, materials and techniques cautiously for themselves and to consult appropriate professional resources to determine whether information, materials and techniques are suitable in their case.The drawings and text are intended as general practice guides only. Project and site-specific factors of climate, cost, aesthetics, and so on must be taken into consideration.Any photographs in this book are for illustration purposes only and may not necessarily represent currently accepted standards © 2001 Canada Mortgage and Housing Corporation All rights reserved. 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Printed in Canada Produced by CMHC TABLE OF CONTENTS INTRODUCTION . 1 ENHANCING ENVELOPE DESIGN . 7 ENHANCING ENERGY PERFORMANCE. 29 ENHANCING INDOOR AIR QUALITY . 57 ENHANCING ENVIRONMENTAL PERFORMANCE. 71 ENHANCING ACCESSIBILITY . 101 GREEN INFRASTRUCTURE. 109 Page i INTRODUCTION THE NEED FOR CHANGE High-rise residential buildings play an important In all too many instances, repair costs for new role in expanding Canadians’ housing choices. buildings are being assumed by Warranty The buildings provide housing choices ranging Programs, thus depleting their reserves. In from affordable housing for low income renters Ontario alone, warranty claim payouts for through to luxury units in some of Canada’s most high-rise buildings are approaching $20 million prestigious locations. It is estimated that 20% of annually. Canadians live in multi-unit residential buildings. Researchers, architects and engineers in the field While the benefits of these housing choices are agree that better performing buildings can be generally considerable - proximity to services, constructed. They acknowledge that improving public transportation, efficient use of land and performance will require changes in the design infrastructure - the quality of the housing units and construction process, requiring more has not reflected recent technological advances. comprehensive and improved building detailing, enhanced quality control and building A list of common inadequacies include: commissioning processes, improved building operation and maintenance procedures, and • water penetration and air leakage through the understanding the building construction and building envelope resulting in structural and operation as a whole. other damage, high energy cost and occupant discomfort, Over the last several years, building scientists, • inadequate thermal envelope performance and researchers and practitioners with considerable thermal bridging resulting in occupant expertise have invested substantial resources and discomfort and high energy bills, energy in identifying the causes of typical • HVAC systems influenced by strong building problems in high-rise residential buildings, and stack effects and wind pressures which result in developing improved design and construction in poor comfort levels and poor indoor air procedures that could significantly reduce defects quality, and improve building performance. • insensitive use of land which impacts on stormwater flow, An improved understanding of all facets of high- • high domestic water consumption, rise design and construction is being developed • occupant dissatisfaction relating to noise relating to virtually every aspect of high-rise levels, buildings. Upgraded parking garages, enhanced • a lack of accessibility to people with envelope durability through rainscreen and air disabilities. barrier design, improvements to the building thermal envelope, better heating, cooling and These problems are not solely those of the building mechanical ventilation systems, measures to occupants. Increasingly across the country, the cost improve the accessibility and functioning of of remedial repairs and replacement of buildings, and measures for improving the deteriorating components of the building are being environmental performance of these buildings legally passed back to the developer. and the inter relationship between these systems have all been the subject of recent investigation by government and housing agencies. Page 1 Healthy High-Rise Canada’s building design and research community Opportunities are also discussed for improving has historically been at the forefront of innovation the integration of high-rise residential buildings in the Canadian construction industry, maintaining with the surrounding urban infrastructure, our reputation for providing some of the best including on-site systems for energy and water housing in the world. Until recently, much of the supply, transportation and waste management. innovation was concentrated on the low-rise housing stock where we are acknowledged as Finally, each section includes “Sources of world leaders in the provision of energy efficient, Information” to recent research and development environmentally-responsive housing. It remains studies. The industry is encouraged to follow-up for the high-rise design and building industry to on these reports that reflect some of the best and assume a similar leadership role. most current information on high-rise buildings. This document is designed to reflect the innovation As innovative practices are adopted, implemented that can lead to the design and construction of and monitored in high-rise buildings, our better performing buildings. It provides: knowledge and understanding will be greatly enhanced. Readers are encouraged to share their • an overview of many of the problems experiences with CMHC. affecting high-rise buildings which result from conventional practices, • insight into an improved understanding of the building science principles, and • design considerations for improving building performance in a variety of areas. This document is intended to present alternative ways of thinking about design principles for high- rise buildings, to provide some different approaches to design, construction, commissioning and operations and maintenance. In many cases, it presents the need for a more holistic and integrated approach to the design and construction of a high-rise residential building. This type of integration is displayed in the “Related Topics” table at the beginning of each sub-section. Issues related to retrofit opportunities and regional differences are also discussed when they apply. Page 2 Introduction BUILDING FAILURES THE PROCESS contractors is ad hoc and project quality control