Wood is an excellent renewable material
used in the building industry. However, being
organic, it can be attacked by pests like wodworm
(insects) and dry rot (fungi). To prevent this
it must be reated with preservatives before
Traditional wood preservatives contain
chromium copper arsenate (CCA). Although studies
have shown CCA to be safe, some groups have
raised concerns about arsenic getting into
the environment. Arch Timber Protection have
developed treatments that are free from arsenic
but just as effective as CCA.
"Tanalith E" uses copper
and an organic azole biocide as its active
ingredients. Treated under pressure, the Tanalith
E penetrates deep into the wood and chemically
links to it. This gives the wood protection
against attack by insects and fungi for many
Another product, "Vacsol Aqua",
contains completely biodegradeable fungicides
and insecticides. It can be used to treat wood
that is used in the construction of houses.
Pressure treatment with Tanalith
Timber is placed in
a chamber and all the air is pumped out. This
vacuum draws water out of the wood cells.
Chamber is flooded with solution
of Tanalith E.
Pressure is applied to force
solution into timber.
Excess solution is pumped out
of chamber. Wood is kept under low pressure
in a vacuum.
When chamber is opened to atmospheric
pressure, the final surface layer of Tanalith
E is forced into the wood.