Lisø PhD Dissertation Manuscript - NTNU

will most likely be worse, even with small increases
in temperature.
Wood is the most common cladding material for
dwellings and smaller buildings in Norway. The performance
of a wooden cladding depends largely on
the quality of the wood material, the surface coating
and the construction details. The recommendations
for use of wood as cladding material has been unchanged
for many years, though there are arguments
claiming that an air space between the cladding and
the wind barrier might not always be necessary.
Gypsum boards are often used as airtight sheathing
in buildings. A vapour permeable and water repellent
membrane (breather membrane) are often
recommended for buildings being erected in coastal
areas, in addition to the gypsum board. Further studies
on the mechanisms of ventilation and drainage of
different outer wall constructions in different climate
zones will be carried out, in order to better understand
the necessity of water vapour resistance of
wind barriers. The studies will be based on Geving
& Uvsløkk 2000.
Increasing amounts of precipitation and severe
driving rain conditions will put the current construction
practice for brick veneered walls to test. Laboratory
tests carried out by Kvande (1994) demonstrates
the capability of such walls to withstand extreme
driving rain conditions as long as the performance
matches the current requirements. Efficient ventilation
behind the outer leaf has to be ensured in brick
veneer wall constructions to resist driving rain, and
to avoid moisture damage. There will always be possibilities
for rainfall to penetrate the outer leaf.
Hence, a drainage system is also necessary to ensure
that water penetrating the outer leaf is effectively
drained.
6 THE WAY FORWARD
6.1 The Climate 2000-programme
The prospect of an even harsher climate in parts of
the country means that we must pay more attention
to the design, construction and geographical localisation
of the built environment, and be more aware
of the climatic impact buildings will have to endure.
Hence, there is a clear need to further develop our
knowledge, methods, tools and solutions in principal
concerning the planning and design of buildings in
severe climates, to ensure a reliable building stock in
the future.
This forms the background for the initiation of
the Norwegian Research & Development Programme
“Climate 2000 – Building constructions in a
more severe climate” (Lisø et al. 2002). The programme,
which consists of 14 different projects, is
being managed by NBI and carried out in cooperation
with a large number of key actors in the
construction industry. It was initiated in August
2000, and will continue until the end of 2006.
The programme’s principal objectives are to:
− Survey and increase the knowledge about possible
impacts of climate change on the built environment
and how society can best adapt to these
changes.
− Develop and update methods, tools and solutions
in principal for the planning and design of buildings,
resulting in both increased durability and reliability
in the face of external climatic impact.
− Define more accurate criteria and Codes of Practice
concerning building performance in severe
climates.
Both the functionality of the existing built environment
and the design of future buildings are likely
to be altered due to possible impacts of climate
change, and expected implications imposed by these
new conditions will be investigated.
6.2 Review of the Norwegian building stock and
building practice
A thorough review of the Norwegian building stock
and building practice will be carried out within the
Climate 2000-programme, to evaluate how different
types of buildings and structures are vulnerable to
possible impacts of climate change. The “robustness”
of the Norwegian building stock will be assessed
through analysis of statistical data, along with
NBI’s experience related to building damage. Statistical
data for building types, year of construction,
material use, building and construction design and
geographical localisation are available. Historical
trends in the design and construction of buildings
and built environments will also be studied. Historical
weather data and statistical data from insurance
companies (natural damage) will serve as a basis for
the analysis.
Information on all these elements needs to be
elaborated systematically. Geographic Information
Systems (GIS) tools will be implemented for the assessment,
mapping and presentation of climate
change risk factors. Risk and vulnerability assessment
methods concerning building performance in a
potentially more severe climate will also be developed.
This work will include development of methods
for classifying different climate parameters and
their impact on buildings, and the preparation of a
thorough overview of the relevant climate variables
that should be taken into account during the planning,
design, construction, management, operation
and maintenance of the built environment. A Climate
Index Approach for selecting Design Refer-