Quantcast Visual Decay Detection

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Openings may result from deep seasoning checks, from gouging by
pointed tools, from loosened fastenings such as bolts, or when cuts or
holes made after treatment are left unprotected. That is why it is vitally
important to treat with preservatives, all areas that are exposed to prob-
ing, cutting or drilling. Periodic retreatment of areas prone to moisture
contact and accumulation must also be done on a scheduled basis.
3.2 Visual Decay Detection. The color of wood may or may not
indicate whether it has become decayed. As wood approaches the ad-
vanced stages of decay it loses its luster and may experience notable
changes in color and become either much darker or much lighter than
non-decayed wood. In the early stages, however, the wood may appear
unchanged although it may have lost substantial strength, particularly in
shock resistance.
The presence of fruiting bodies [Figure (2)] indicates that a decay fungus
is present in the member where the bodies occur. Some fungi produce
fruiting bodies at the wood surface after little or moderate decay while
others do not produce fruiting bodies until after extensive decay has oc-
Another visible clue to the presence of decay is the localized depression
or sunken faces over decay pockets which extend close to the surface of
the member. Termites, carpenter ants, and beetles often are associated
with decayed wood and signs of infestation by these insects may be
evidence of decay.
A number of signs provide visual evidence of existing conditions that
may be conducive to decay. Areas exhibiting these signs should be in-
spected carefully. Evidence of water, such as watermarks may indicate
areas of decay. Such areas should be checked with a moisture meter,
such as a shigometer or pilodyn [Figure (3)]. If their moisture content is
above 20%, the wood is wet enough to support fungal growth. If their
moisture content is near 30%, decay likely is in progress. Rusted nail
heads, screws or bolts also indicate that wood is being wetted. Notice-
able growth of moss or other vegetation on wood surfaces or in checks or
cracks is evidence of potentially hazardous wetting. Special attention
should be paid to wood adjacent to water-trapping areas such as joints
where end-grain is exposed to rain, wetting, or other sources of moisture.
Wood primarily absorbs water through end grain, so decay often begins
at joints.


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