Assessing the relative environmental impact of different building materials
is a nightmare, one that designers with an interest in sustainability
battle with constantly. When it comes to a choice between concrete and
timber we have a numbr of issues.
Creating concrete requires the procesing of limestone. This is energy
intensive. Carbon dioxide is also liberated directly by the chemical
process. (making areated concrete is more energy intensive even than
"ordinary concrete" though this might be traded of through its improved
insulating value)
In the UK some of our limestone reserves are in, or adjacent, to National
Parks! The aggregates used in concrete also need to be quarried and on our
small island we have difficulty in deciding which landscape to sacrifice.
Timber is seen to have advantages because it is a renewable resource and in
the long term is carbon neutral. (From growth to use to decay). (and trees
look prettier than a mechanised hole in the ground (even the rigid rows of
conifer plantations))
I am sure that John could tell us that sustainable forestry is problematic
(lack of bio-diversity in plantations is one) but the alternatives are not
cost free either. While individuals involved in design might want to make
ethical decisions (re sustainability) it is diifficult to do so in tha
face of this complexity.
Regards Paul K
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