Lisø PhD Dissertation Manuscript - NTNU

Lisø, K.R./ Building envelope performance in harsh climates: Methods for geographically dependent design
2.1 Introduction
2 Main findings
The dissertation is divided into three mutually dependent main parts (part A-C). Each
part consists of four papers (see List of papers).
Approaches to assessments of the risks associated with climate change and building
envelope performance are presented in Part A, identifying main areas of vulnerability
in the construction industry. Norwegian climate policy is briefly reviewed and the
predicted climatic changes over the next decades are described. Climate vulnerability
is explained, and possible adaptation policies are suggested (Paper I). This is
followed by an overall view of building physics related challenges concerning the
design of building envelopes, together with a few detailed climate change scenarios
for Norway (Paper I and Paper II). A way of analysing the building economics of
climate change is also proposed (Paper III). The model describes important aspects
to be considered and identifies stakeholders, and the paper discusses
interdependencies between potential implications of climate change and the
behaviour of building owners. Finally, ways of using modern risk management
theories as a basis for the development of strategies to meet the challenges of future
climate change is presented. It is shown that there are benefits to be gained from the
introduction of risk management strategies within a greater extent of the construction
industry (Paper IV).
An overall review of the robustness of the Norwegian building stock is presented in
part B, focusing in particular on analyses of empirical data from process induced
building defect assignments as a point of departure for climate impact differentiation
assessments. Analyses of building defects are essential in order to further develop
tools and solutions ensuring high-performance building envelopes. To illuminate the
vulnerability of building envelopes under varying climatic exposure, a
comprehensive analysis of building defects is carried out (Paper V). The overall
analysis presented in Paper V is supported by two case studies on building defects
(Paper VI and Paper VII). The case of flashing (Paper VI), a central part of all
building envelopes, is chosen to illustrate that parts of the building envelope are
particularly vulnerable to defects, and thus justifying a higher level of robustness
than other parts of the envelope. Simplified flashing solutions could be acceptable in
some areas, but it is an inexpensive insurance to choose flashing solutions with a
higher climatic level of reliability. A comprehensive review of process induced
building defect assignments related to masonry shows that the performance of
masonry depends on climatic exposure at the very local level. The case of masonry
structures (Paper VII) clearly reveals the fundamental need for climate differentiated
design guidelines and recommendations. Finally, results from a field investigation of
structural safety in different vintages of buildings compared with current regulatory
requirements are presented in Paper VIII.
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