Page 34 - Haddonstone
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7.1 Prevention
Every effort should be taken to protect the However, routine maintenance of other
cast stone units from contamination. Care elements of the building fabric is important
taken in transit, storage, fixing and protection and such examples are keeping gutters,
during construction virtually negates any roof coverings, flashings and hoppers in
requirement for additional work. good working order. Joints should be kept
properly pointed, excessive vegetation
Cast stone should not, in the natural removed or controlled, ferrous metal
course of events, require any maintenance painted and judicious cleaning undertaken
over many years. The product will weather when necessary.
in a similar way to natural stone and
consideration should be given to prevailing
climatic conditions at design stage.
7.2 Cleaning
Cleaning is most frequently undertaken for 7.2.1 Precautions
aesthetic reasons. However, sometimes
there are sound practical grounds for Before the application of any treatment
removing dirt when, for instance, decay to cast stone it is recommended that the
is taking place around encrustations and supplying UKCSA member is contacted for
cracks or open joints are being obscured. advice. Any subsequent treatment should
be tested on a small sample area in an
Before undertaking any cleaning of inconspicuous place prior to any major
cast stone there are several important application.
considerations to review.
7.2.2 Pointing
• Cast stone behaves in a similar way
to natural stone and the precautions Particular attention should be paid to
required for cleaning the natural material the condition of the joints prior to the
should be adopted with cast stone. commencement of any cleaning programme.
These should be inspected to ensure that
• Any cleaning will expose the underlying the pointing is in a sound condition.
cast stone and various elements of the
structure may have weathered differently 7.2.3 Health & Safety
causing changes in colour. The effect
after cleaning may be a patchy finish. • In all cases of cleaning professional
advice and/or the advice of the individual
• Although cast stone elements may get manufacturer should be sought prior to
dirty, this is usually unlikely to cause any the commencement of any treatment.
particular problem unless the encrustation
of dirt is causing decay to the surface, or • Always use experienced operatives
staining the underlying stone, especially for the cleaning process and follow
at street level. In these cases some the cleaning material manufacturer’s
remedial action may be appropriate. instructions.
