Lisø PhD Dissertation Manuscript - NTNU

1.2 The extent of building defects in Norway
The historical development of Norwegian building
traditions implies both an adaptation towards different
preconditions for use of buildings and varying
styles of architecture, but also an adjustment towards
the extreme climatic variations in Norway. Changes
in building practice also reflect the economic development
and new demands in standard of living. The
extremely varied climate and topography in Norway
puts great demands on the design and localization of
buildings and the correct choice of materials and
constructions. A definitive minimum requirement for
a building is that it should tolerate to be left outside.
Natural disasters caused by extreme weather
events are one of the major challenges confronting
the built environment. However, the amount of
building defects not covered by natural disaster insurance
is also tremendous. The increasing demands
in the construction industry for profit and shorter
construction periods, combined with extremely varied
climatic impacts during the construction process,
prove to be a difficult circle to square (Lisø et al.
2003). Investigations carried out by SINTEF Building
and Infrastructure indicates that the cost of repairing
process induced building defects in Norway
amounts to 5% of the annual capital invested in new
buildings (Ingvaldsen 1994). Ingvaldsen also found
that this estimate was in good agreement with 13
corresponding investigations or sources of information
in other European countries (with a mean estimate
varying between 3-5%). Correcting faults and
repairing defects in buildings during the construction
process is estimated to cost roughly the same amount
as repairing buildings in use, e.g. another 5% (Ingvaldsen
1994). With an annual investment in refurbishment
and new construction of NOK 130 billion
(as in 2003), it is reasonable to estimate that approximately
NOK 13 billion is being spent on repairing
defects or damage to buildings every year.
The Danish Building Defects Fund is the primary
source of information on building quality for the past
10-15 years in Denmark. The Fund carries out yearone
and year-five inspections on all publicly subsidised
housing. The Fund’s database comprises information
on more than 2.000 building defect inspections
carried out by use of random sampling.
Major deficiencies (the definition of “deficiency” is
by and large equivalent to Ingvaldsen’s definition)
have been registered in 5% of the year-one inspections
and in 25% of the year-five inspections
(Byggskadefonden 2005).
1.3 Government regulatory measures and building
quality
Ways to strengthen institutional capacity to implement
appropriate building performance requirements
and standards, and thus reducing the sensitivity of
the built environment, is an important element in ad-
aptation to climate change (Lisø et al. 2003), and
naturally also when trying to adapt the built environment
to the prevailing climate. The present general
trend in legislation and regulation away from
prescriptive rules to performance-based codes will
increase the need for interaction between regulatory
decision makers and substance matter experts (Rasmussen
1997).
The most important government regulatory measure
to ensure adherence to building codes and standards
is the Technical Regulations under the Norwegian
Planning and Building Act (PBA), which since
1997 have been performance-based. The principal
motive for a transition from a prescriptive code to a
performance-based code in Norway was to contribute
to an increase in the quality of buildings and a
reduction of the amount of building defects. Preliminary
findings from a case study of process induced
building defects suggest that the adoption of a performance-based
building code has indeed led to a
positive change in quality (Mehus et al. 2004). However,
even if the amended PBA appears to be contributing
towards improved quality of construction,
defects, flaws, and premature damage are still flourishing
in new construction. Furthermore, design of
details crucial to durability and service life of buildings
is often omitted or they are improvised on site
(Stenstad et al. 2005).
The transition from a prescriptive to a performance-based
code has strengthened the demand for
supporting standards and design guidelines. The
Building Research Design Sheets in the SINTEF
Building Research Series comply with the performance-based
requirements in the building code, and
are important references to “pre-accepted” solutions
in the technical regulations. The principal objective
of the Design Sheets is to adapt experience and results
from practice and research in such a way that
they can be of practical benefit to the construction
industry. The main purpose is to provide guidelines,
solutions and recommendations that encourage high
quality in the planning, design and construction of
buildings. The series consists of more than 800 design
sheets, the first sheets being published in 1958.
It is by far the most used planning and design tool
amongst Norwegian architects and engineers and is
found on nearly all construction sites. The Design
Sheets are continuously being updated to comply
with the building code and experience-based knowledge.
However, the technical solutions presented in the
Building Research Series are in general meant to
have a reliability level suitable for all parts of the
country. The “robustness” of the Norwegian building
stock, including the development of methods for
classifying different climatic parameters and their
impact on building envelope performance, are now
being addressed as part of the research & development
programme “Climate 2000”.