Lisø PhD Dissertation Manuscript - NTNU

2. Masonry defects in Norway
2.1. Source and method
SINTEF Building and Infrastructure’s archive of process induced building defect
assignments represents one of Norway’s most important sources of knowledge on types of
building defects and related causes [3] [4]. SINTEF Building and Infrastructure has
undertaken analyses of building defects for more than five decades, both on behalf of the
construction industry and in comprehensive field investigations. General information on
these assignments is filed in the institute’s central archive, and registered electronically.
Ingvaldsen [5] defines “process induced building defects” as absence or reduction
of presupposed capacity that is discovered after a construction project has been completed
and taken over by the owner, and which he demands to be repaired. Thus, process induced
building defects bring about exceptional maintenance costs, i.e. cost that should not have
been incurred – or additional costs related to more frequent maintenance than forecast.
This is because the actors involved have not succeeded in fulfilling the requirements of
standardised or generally recognised methods or specifications. Defects caused by normal
wear and tear are not defined as building defects. The same goes for damage due to fire or
natural damage, damage which is not included in this definition.
The expensive lessons learned described in the previous section should be
employed to good purpose in new building. Altogether it is found that SINTEF Building
and Infrastructure has more than 5,000 process induced building defect assignment reports
in its archives [3] [5]. The ongoing establishment of the archive allows for in-depth
analyses of causal relations of different types of building defects on a wide variety of
building envelope elements. Results from a comprehensive investigation of the paper
copies of 302 process induced building defect assignment reports inflicted on masonry
structures for the 20-year period 1983-2002 are presented in this paper, adopting the
definition above (in the following referred to as “process induced masonry defects”).
2.2. Results
Defects related to the building envelope constitute about two thirds of the about 2000
investigated cases in the 10-year period 1993-2002 [3]. Defects related to external walls
above ground level constitute 29% of the cases (see Fig. 1), about half of these related to
masonry structures. Moisture as the main source causing the defect accounts for as much
as 76% of all investigated cases. Many types of building defect cases are recurring items,
which indicate a general lack of knowledge amongst the different actors in the construction
industry concerning fundamental principles of building physics [3].
LECA masonry
32 %
Concrete walls
10 %
Brick cavity or veneer walls
17 %
Other
3 %
Timber framework
30 %
Metal framework
7 %
Sandwichelements
1 %
Fig. 1. Process induced building defect cases for the 10-year period 1993-2002 (a total of about 2000
building defect cases), distributed by type of external walls above terrain [3].
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