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Looking for Wood Decay |
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It is important to know why and where a particular element
has failed prior to the establishment of the "how" |
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Defining a detailed
scope of work on an element by element basis allows the owner/building manager,
and contractor to get a realistic handle on costs, time and materials required,
and feasibility of repair vs. replacement. Simply stating "repair as
required" leaves a great deal to individual interpretation resulting
in wide differences in the contractor's bids. This ambiguity causes schedule
delays, compromise of quality, and costly change orders.
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| The basic criteria for a
comprehensive inspection can be categorized in two basic areas: |
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(1) Condition of paint
(2) Substrate condition |
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#1 The Condition of the Paint
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Paint is the first line of defense to moisture and sun degradation.
Often the assessment of a building's condition is made strictly
from the quality of the paint film. Usually only 5% to 10% requires
repair. Paint failures are usually related to age or substrate
problems. |
Failure of Brittle Wood Filler |
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The older alkyd and linseed
oil based paints turn brittle over time resulting in the alligatoring
and chalking of the paint film. Peeling paint often signals poor surface
preparation or high moisture content levels. Use a
cross-hatch
adhesion test to analyze the bonding quality of the paint. |
#2 Substrate Condition
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When inspecting the condition of the exterior elements, it is important
not to rely strictly on visual clues. Probing with an awl or pen knife
will allow one to "see" beneath the paint film and examine the
condition of the underlying substrate. Modern paint systems allow considerable
moisture to penetrate without exhibiting any outward signs of failure. |
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The areas where water collects
and penetrates are the most vulnerable to damage. |
| Sills, bottom rails, lower
brick moldings, porch columns, and wooden gutters are most effected. Exposed
end-grain, open joints, checks or fissures, and cracked glazing compound
all permit moisture to penetrate below the surface. The quality of old
growth wood can take considerable moisture and ultra-violet light and
show only surface degradation. Just a 1/4" to a 1/2" below the
surface may lie some very solid material. |
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Increasing evidence of past
attempts at repair are discovered. Due to differences in expansion and
contraction, dutchman splices often de-adhere and promote decay of the
surrounding area. |
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Brittle repair materials, together with
inadequate surface preparation, cause
adhesion
and cohesion failure.
Based on this comprehensive inspection,
the building owner/manager and contractor now possess the information
necessary to assess where and why the failures have occurred. The simple
step now becomes translating the findings into the marching orders needed
to get the job done.
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Step-by Step Instructions |
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