CHAPTER 2. INSPECTION METHODS
Section 1. EQUIPMENT
The actual equipment necessary for examination of wood trusses and glulam
arches is relatively simple. It should include adequate means of lighting; hand
tools for measuring. probing, and boring; and an instrument for measuring
moisture content of wood. To augment written notes in the case of unusual cir-
cumstances, a camera may be included.
2.1.1 LIGHTING. Trusses are often located in dark areas of the building,
so some type of light that is adequate and convenient is needed. In some cases
a trouble light may be used. Where examination is at extreme heights or other-
wise inaccessible locations a strong flashlight may be more convenient.
2.1.2 LIFTS. Some method of reaching the top of the building from the
inside must be provided. In warehouses, cranes that run the length of the building
may give easy accessibility. The use of a cherry-picker is another possibility.
Where roofs are not as high, examination may be done with ladders, platforms
on forklifts. or front-end loaders.
2.1.3 LINEAR MEASUREMENTS. A small measuring tape should be
available to measure defects such as width or length of checks and splits. A length
of fishline or other type of cord may be needed to stretch between truss ends
to check the amount of deflection of the truss at the center. Also, a thin feeler
or thickness gauge is needed to measure depth of checks or delamination.
2.1.4 PROBING. A moderately pointed tool such as an ice pick or fine-
bladed screwdriver is useful in detecting decay that extends close to the surface.
2.1.5 SOUNDING. A hammer or other suitable tool is needed to rap the
outside surface of a timber. The resulting sound may indicate the presence of
2.1.6 DRILLING. The removal of chips with an auger bit (1/4-or 3/8-in.)
is used to determine the presence of internal deterioration.
2.1.7 TREATED WOOD PLUGS. Where boring is done, treated plugs
are used to close the resulting holes.
2.1.8 MOISTURE CONTENT. A moisture meter with 3-inch insulated
pins is needed to determine moisture content.
2.1.9 PHOTOGRAPHY. A camera that will take pictures with good
resolution is desirable to provide a record of unusual circumstances. A good
flash attachment is also desirable.