Chimneys
and Flues
There are a wide variety of chimneys, which
represent an even wider variety of interrelated components that comprise them.
However, there are three basic types: single- walled metal, masonry and
pre-fabricated metal ones that are commonly referred to as factory-built.
Single-walled metal chimneys should not be confused with factory-built chimneys,
and are rarely found in residential use, but masonry and factory-built ones are
a commonplace.
My inspection of chimneys is that of a generalist not a specialist, and meets
industry standards. However, significant areas of chimney flues cannot be
adequately viewed during a field inspection, as has been documented by the
Chimney Safety Institute of America, which reported in 1992: "The inner
reaches of a flue are relatively inaccessible, and it should not be expected
that the distant oblique view from the top or bottom is adequate to fully
document damage even with a strong light." Therefore, because my inspection
of chimneys is limited to those areas that can be viewed without dismantling any
portion of them, and does not include the use of specialized equipment, I will
not guarantee their integrity. I recommend that they be video-scanned before the
close of escrow.
CHIMNEY FLUES
Chimney flues need to be cleaned
periodically, to prevent the possibility of a chimney fire. However, the complex
variety of deposits that forms within the chimney flues as a result of
incomplete combustion, and which contribute to such fires, are complicated and
not easily understood. They range from soot or pure carbon that does not burn,
to tars that can ignite. All of these deposits are commonly described as
creosote, but creosote has many forms, ranging from crusty carbon deposits that
can be easily brushed away, to tar-glazed creosote that requires chemical
cleaning. These deposits must be identified and treated by a chimney specialist.
However, cleaning a chimney is not a guarantee against a chimney fire. Studies
have proven that a significant percentage of chimney fires have resulted within
one month of the chimney being cleaned and many more have resulted within a
six-month period.
It is impossible for Olympian Home Inspectors to determine with any degree of
certainty whether all flues are free of defects. In accordance with
recommendations made by the National Fire Prevention Association to have all
chimneys inspected before buying a home, you should consider having a C S I A,
or equivalently certified chimney sweep, conduct a Level II inspection of all
chimney flues prior to close of escrow.