Copyright
2006, Delmhorst Instrument Co.
Page 25 of 32
PAINT FAILURE AND MOISTURE
Moisture is by far the most frequent cause of paint failure. The key to preventing paint
failure is to insure that moisture is not absorbed through the wood to the back of the
paint film. So, in order to insure quality paint jobs, wood must remain dry after the
application of paint.
Outdoor wood can be safely painted without danger of peeling if the %MC is 15% or
less. In drier climates, the maximum reading should be 10% to 11%. Indoor wood
should be between 7% to 8% prior to painting.
The following conditions may cause high moisture content in wood:
⇒
Leaky gutters and down spouts
⇒
Leaky pipes or condensation on cold water lines in attic or hollow walls
⇒
Faulty flashing around windows, doors and where porch and dormer roofs meet
sidings
⇒
End-grain wood that is not sealed with paint at all joints around windows, corners,
and butt joints
⇒
Porch columns that do not have good drainage and ventilation where they rest on
porch floors
⇒
Siding or any other wood that is in contact with the ground may absorb moisture
⇒
Siding and shingles without sufficient lap so that water is forced up through cracks by
wind pressure
⇒
Ice dams
⇒
Condensation of vapor within hollow walls
EIFS (Exterior Insulation & Finish Systems
) *
Moisture intrusion problems in EIFS (also known as synthetic stucco) stem from leaking
window frames, improper use of or lack of sealant, and faulty installation of flashing.
If you suspect a problem take a visual inspection. Look for gaps around windows, doors,
air conditioning units, light fixtures, hose bibs, dryer vents and other areas of potential
penetration. Also look for visible signs of water damage. If you feel a problem exists, use
the
TotalCheck
with a
# 21-E electrode
. This electrode includes the
#608 - (4")
insulated pins or #608/001 (6”) insulated pins in EIFS Package.
Procedure:
⇒
Drill two 1/4" holes
about ¾” apart at an upward 45° angle.
⇒
Push the # 21-E Electrode into the holes
through the polystyrene and into the
substrate.
⇒
Press the SELECT button
and read the moisture content on the meter scale. The
meter displays the %MC for two seconds.
⇒
To add a reading to the
previously stored readings, release the SELECT button if
you are in triggered mode. If you are in continuous mode, the meter will not store a