by Deanna Freer
Historically, masonry
is the most durable of all building materials. Masonry is often easier
to maintain than its wooden counterparts, but when repairs are
necessary, they can be very expensive and problematic. Masonry buildings
are susceptible to damage by improper maintenance, poor repair
techniques and harsh or abrasive cleaning methods. For the purpose of
this article, historic masonry includes stone, brick, cast stone,
concrete and concrete block.
Prior to making any
repairs on your masonry building, you should take the time to determine
what the cause of the problem might be. If this step is overlooked, the
damage could continue in spite of repairs. Some causes may include:
leaking roofs and gutters, settlement of the foundation or exposure to
the elements.
If you believe the
cause of the problem relates to the settlement of the foundation, it is
important to have a structural engineer or qualified professional look
at it. Foundation settlement causes cracks and widening of the joints.
It is important to determine if the movement is active or stable. If
settlement is gradual or has ceased, the solution may be simply to
repoint (replacement of missing or damaged mortar). If settlement is
active, you may need to repair the foundation as well as the mortar.
Water is often the
main cause of damage to masonry buildings. Rain and snow can lead to
plugged gutters, roof leaks and malfunctioning rainwater leaders. This
uncontrolled water infiltration often results in the weakening or the
disappearing of mortar. It is important to provide proper drainage so
that water does not stand on flat, horizontal surfaces or accumulate in
decorative features. By insuring proper drainage, your masonry will last
longer and not require expensive repairs.
Repair and maintenance
procedures for masonry surfaces include rebuilding, repointing, cleaning
and the application of coatings. Some repairs are essential as damaged
or collapsed masonry will need rebuilding. Proposals for cleaning or the
application of coatings should be carefully considered. There could be
consequences to these choices and they are quite costly. For example,
cleaning masonry may result in the loss of some of the original material
and is only justifiable when pollution or dirt is actively causing
deterioration.
Masonry should only be
cleaned in order to halt a building’s deterioration or to remove heavy
soiling (i.e., pollution, dirt and moss). Proper cleaning methods, when
deemed necessary, can enhance the aesthetic characteristics and the
structural ability of a historic building. Removing years of dirt can
extend the life and longevity of a historical resource.
If cleaning is
considered appropriate, a very gentle method should be used. The most
common method is to use water, detergents and natural bristle brushes.
Masonry should never be sandblasted or cleaned with abrasives. These
methods erode the surface of the material. Also, chemicals that will
permanently damage the masonry, such as acids or solvents, should never
be used.
If a masonry building
requires repainting, damaged paint should be removed using the most
gentle method possible. This is usually entails a soft bristle brush and
non-corrosive chemicals. When repainting, the replacement colours should
be historically appropriate. Remember, you should not paint a previously
unpainted masonry surface, as it rarely complements the design and often
drastically alters the appearance of the building.
Repairs to a masonry
building can be done on your own, but it is best to consult with a
professional who specializes in heritage restoration work or who is
prepared to undertake further study of the building. The results of a
restoration project carefully planned and properly prepared will be
worth the effort. Please keep in mind that the repairs to masonry
features should only be considered when there is evidence of
deterioration or damage. A change to historic masonry surfaces can
visually impact the entire character of the building.
If you have any
questions regarding masonry, or would like to receive more information,
please contact the Planning, Building and Licensing Department at (250)
837-3637.
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