Timbers and poles exposed to wetting can decay when water remains in
contact with them or whenever water which has entered the wood cannot
escape, unless they are periodically retreated in the sections where a high
decay hazard exists. Typically, decay can be found where untreated wood
has been exposed at seasoning checks or bolt holes that permit water to
enter the wood.
Preservative-treated timbers may decay when openings permit water to
penetrate beyond the treated shell. Openings may result from deep season-
ing 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 preservative any areas that
are exposed to probing, cutting or drilling and to periodically retreat areas
where water can enter wood or accumulate adjacent to it.
1.4.2 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 looses 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 percentages of its strength,
particularly in shock resistance.
The presence of fruiting bodies 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 occurred.
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 evidence of infestations by these insects may be evidence
A number of signs provide visual evidence of conditions conducive to decay
and areas exhibiting these signs should be inspected carefully. Evidence of
water, such as watermarks may indicate areas of decay. Such areas should
be checked with a moisture meter. 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