Lisø PhD Dissertation Manuscript - NTNU

flashing techniques were involved in approximately
25% of all the masonry defect cases (Kvande &
Lisø, submitted). Furthermore, the last mentioned
investigation concludes that shrinkage and thermal
expansion/contraction without the necessary countermeasures
are the most common cause of masonry
defect, registered in one third of all cases of defects
analysed (302 process induced building defect assignments
related to masonry in the 20-year period
1983-2002). This investigation also reveals that two
thirds of all cases comprise faults in the execution of
the actual rain barrier (non water-tight mortar joints
and rendering), drainage from the air gap (insufficient
air gaps, mortar bridges between outer leave
and rear wall as well as missing drainage openings at
bottom of wall) and the execution of window and
parapet flashing.
4 DISCUSSION AND LIMITATIONS
The analysis is based on building defect assignments
carried out by SINTEF Building and Infrastructure
and thus cannot aspire to represent a complete and
definitive overview of process induced building defects
in Norway. In geographic terms, building defect
assignments forming part of the investigated 10year
period have been carried out in 182 municipalities
out of a total of 436 municipalities in Norway.
However, a major part of the cases of defects are located
in municipalities near SINTEF Building and
Infrastructure’s offices in Oslo and Trondheim. This
is due to the institute having easier access to building
defect assignments in its vicinity. The municipalities
of Oslo and Trondheim alone reply for 38%
and 11% of the investigated cases respectively.
There is naturally a wide range of causes as to
why the different actors within the industry contacts
SINTEF for an expert opinion, assessment or investigation
of a building defect incident. In most cases
the client is concerned with the extent of the defects,
and loss of reliability or reductions in lifetime of the
component exposed to damage. The clients also often
want advice as to how the defect or damage
should be repaired.
In some cases the institute is addressed to settle a
dispute between different actors involved in the construction
process. The institute is also used as independent
experts in cases to be solved by the judicial
system. It is therefore important to emphasise that
only a small part of the total amount of process induced
building defects in Norway emerges in the
SINTEF Building and Infrastructure’s building defects
archive.
The following conditions or circumstances will
contribute to a restriction in the selection of building
defect assignments:
− The probability that a certain defect will emerge
in the archive will be higher the more difficult it
is to find a good solution to the problem, or the
more ambiguously conditions regarding responsibility
are described.
− It is reasonable to assume that the costs involved
in the assignment of the institute as expert advisors
make professional actors dominant. This
probably also explains the large amount of complex
and expensive defect cases in the archive.
Changes in the institute’s time rates compared to
the general economic trend in the society, and
changes in the institute’s price policy, could also
entail changes in the amount and type of defects
to be registered in the archive.
− It is reasonable to assume that the inflow of assignment
reports is strongly related to areas of
expertise where SINTEF Building and Infrastructure
has a good reputation. Thus, changes in the
institute’s competence profile could entail
changes in the amount and type of building defect
assignments.
One of the major advantages with the archive is
clearly the large amount of assignments over a long
time period. Also, the archive contains thorough descriptions
of cause, extent and preventive actions on
complex building defect cases, investigated and described
by highly competent researchers. Despite the
presented investigation having quantitative shortcomings
in terms of general validity, it is an important
step towards a qualitative identification of problem
areas.
The ongoing establishment of the described building
defects archive will be an important tool in both
the continuous efforts towards higher quality in the
construction industry and the development of strategies
aiming at learning from experience. It will also
be a significant instrument in the development of
appropriate preventive actions. The archive will finally
be an important element in the continuous development
of more accurate criteria and Codes of
Practice regarding the design and functionality of
critical elements of buildings in the SINTEF Building
Research Design Series.
5 FURTHER WORK
Empirical observations and modelling increasingly
point to global warming and long-term changes in
the climate system. The Intergovernmental Panel on
Climate Change concludes that most of the warming
observed over the last 50 years is attributable to human
activities, and that anthropogenic climate
change is likely to persist for many centuries. The
presented review of building defects will be further
developed and used to prepare a review of the robustness
of the Norwegian building stock and building
practice. SINTEF Building and Infrastructure, as
an independent institution developing technical
guidelines that reaches out to almost all actors in the