Civil Engineering Reference
In-Depth Information
Figure 16.1: Traditional window construction for single-glazed windows. Source: Jessen 1975
in opening windows there is a bead, usually made of polyurethane or ethylene
propylene rubber (EPDM), but it can also be made of silicone rubber, polyvinyl
chloride, butyl rubber and chloroprene rubber. Woven wool and cotton beading
is probably the most robust. These products can contain fungicide.
Timber windows are based mainly on renewable resources. The consumption
of primary energy is low and production does not pollute the environment sig-
nificantly. Pressure impregnation, plastic beading and metal furniture reduce this
advantage. Timber windows are well suited for local production and create very
few problems in a building, except for a certain level of emissions from impreg-
nated timber and plastic.
Old quality timber frames have lasted for 250 years under favourable condi-
tions. Until the middle of the twentieth century a timber window was considered
to have a life span of 50 years. Since the 1960s, the rotting of timber windows has
increased considerably. Serious damage has occurred as few as 10-15 years after
installation. Sweden's State Testing Station has registered that linseed oil and
alkyd oil paints give timber the best durability (Phil, 1990).
Timber windows of high quality are usually well suited for re-use. Copenhagen's
local authority has calculated a loss of 70 million kroner over the last 10-15 years
