ADMINISTRATIVE REPORT
Date: November 9, 1995
Dept. File No.: LEAKYENV
TO: Vancouver City Council
FROM: City Building Inspector
SUBJECT: Leaky Building Envelopes
RECOMMENDATION
A. THAT Council accept in principle amendments to the Building
By-law to incorporate the new 1995 National Building Code of
Canada (Part 5) requirements for Building Environment
Separators, with a few additional changes which specifically
apply to our rain forest climate to improve the performance of
building envelopes.
B. THAT Council instruct the Director of Legal Services to bring
forward the new by-law changes.
GENERAL MANAGER'S COMMENTS
The General Manager of Community Services RECOMMENDS approval
of A and B.
COUNCIL POLICY
Council has always promoted principles of good building practice through
adoption of modern Building By-laws and cost-effective enforcement.
BACKGROUND
Because water damage to buildings is not a life- or health- related
issue and because "inspection" cannot detect potential leaks, the City
has always relied on the experience of designers and workers to prevent
problems involving building leaks. However, as the traditional skilled
craftsmen gradually become fewer in numbers, the builders must often
employ less qualified tradesmen. The current requirements to prevent
water intrusion are mostly performance-oriented and require experienced
and skilled designers and tradesmen to achieve the performance and
durability required by the By-law.
As you know, unfortunately, we are currently experiencing some
construction which does not perform satisfactorily.
This report proposes more clearly worded, objective-oriented amendments
to replace the present by-law wording. The new requirements of the 1995
National Building Code of Canada (NBC) will basically produce the
quality of building envelopes that were always intended by the present
performance requirements. However, the new requirements would be much
more understandable for the less experienced designers and tradesmen,
and therefore should substantially improve the performance of building
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envelopes constructed in the future.
DISCUSSION
This is another step in our on-going efforts to modernize and simplify
the City's Building By-Law regulations.
As Council may be aware, many buildings have experienced water intrusion
failures during the last few years. The City Building Inspector had
launched a major multi-discipline task group in 1990 to determine the
causes for some of the major failures of exterior insulated cladding
panels. Unfortunately, the members of the task group could not reach a
consensus on the solutions. However, we are now prepared to restrict
the installation of certain panelized products to those prefabricated
and finished at weather-protected assembly sites only or designed as
prefabricated rain screens.
The City was also approached by the National Research Council and
Canadian Mortgage and Housing Corporation to help them solve this
building envelope problem caused by alleged faulty exterior insulated
cladding installations. In 1991, the City Building Inspector was
appointed to a task group studying new wording for the building envelope
requirements. As a result of national input from building envelope
experts, much critical comment from municipalities, and scrutiny from
the public during the recent NBC code revision process, the task group
after 8 meetings finally put together more understandable requirements
for designers, builders and building officials.
These requirements are included in the 1995 edition of the NBC which is
still awaiting publication. However, we can use the wording from the
final draft of the 1995 NBC to adopt into our own Building By-law. With
Council's agreement we would be among the first jurisdictions to adopt
these more effective requirements to help prevent water intrusion. We
are also proposing other requirements more compatible for a rain-forest
climate.
As mentioned in an August memo to Council, we are getting the industry
to address this problem of water intrusion in different ways as follows:
1. Adoption of regulations that are easier to understand.
2. Forming partnerships with the Architectural Institute and the
construction industry in providing workshops to discuss the new
regulations.
3. Involvement of the provincial government's "Ministry of Housing,
Recreation and Consumer Services" brought about to study mandating
of certain trades qualifications and to make changes to the
Condominium Act to protect consumers.
4. Development of a "special" building envelope inspection program for
complex buildings that would be mandatory in the By-law.
5. Discussions with the construction industry to enable us to
recognize acceptable 10-year warrantee programs in lieu of the
"special" building envelope inspection program.
6. Discussions are also taking place between staff and the National
Research Council, who are now proposing a very comprehensive
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research study on Vancouver area micro-climate. This will be a
major study of climate, envelope problems, field monitoring and
necessary durability qualities for most materials. Because of the
complex nature of the study, staff will report back at a later date
to discuss appropriate cost contributions and whether to discuss
the study further.
CONCLUSION
With Council's adoption of new easier-to-understand-regulations, with
the workshops being planned to introduce the regulations, with improved
practice guidelines, with the recent commitment from the provincial
government to recognize additional mandatory trades, with appropriate
changes to the Condominium Act, and with special inspections or the 10-
year warrantee programs, we should see far fewer building envelopes fail
prematurely. With future completion of an NRC comprehensive study, we
should definitely resolve design issues for weather durability in the
long term.
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