A variety of problems may
occur when applying finish, but the source of the
problem is often not the finish itself. Here are of the
most common occurrences and some tips on how to solve
the problem. For the consumer, if these problems occur,
it can help you understand the procedures involved in
having the problem corrected. Here's a quick and easy
checklist to identify and solve problems related to
finishes:
ALLIGATORING
This is a condition in which the finish pulls away from
itself, causing ridges in the finish, similar to an
alligator's skin. This condition can occur in both
water-based and oil-modified finishes. There are many
possible causes, including poor wetting of the finish,
contamination of the finish, application under cold
temperatures, application of a new coat before the
previous coat has dried, application of a heavier coat
than is recommended, or the use of thinners that cause
the finish to dry too quickly. The solution is to screen
and recoat after the finish has dried sufficiently.
APPLICATION STREAKS
This condition is usually associated with water-based
finishes. It often occurs when an improper spread rate
is used - too much or too little finish is applied - or
if the finish is not applied evenly. Excessive air
movement and abnormally high temperatures can also be
responsible for causing the finish to dry too quickly,
so that a wet edge of finish is pulled over one that has
already dried. The problem can also be caused by
applying a satin or semi-gloss finish that has not been
stirred properly. The solution is to screen and recoat
after the finish has dried sufficiently.
BLEED-BACK
This condition, associated with stain application,
occurs when excess stain seeps from the grain or from
the spaces between boards. The most obvious cause is
excessive stain application, but low-viscosity stain may
also be the culprit. The solution is to wipe off the
excess stain and let it dry thoroughly before applying
another coat. If finish has already been applied over
bleed-back, a complete resand is required.
DISCOLORATION
Some finishes are amber in appearance and will yellow
even further over time. Wood lying in direct sunlight
will fade over time. These are natural changes - the
former condition cannot be prevented, despite the
pervasive myth that an oil-modified finish recoated with
water-based finish will stop ambering. The latter
condition can be prevented by shading the light source.
Erratic discoloration can also occur - especially in
white oak - if a good sealer is not used. This is called
tannin pull.
EXCESSIVE AND EARLY WEAR
Often, the cause is improper maintenance procedures that
have either failed to fully remove grit from the floor's
surface, or the introduction of water or strong
cleaners. Dog nails, high heels and chair legs also
contribute to the problem. Make sure the customer
understands proper maintenance procedures, including
regular dust-mopping with an approved wood-floor
cleaner. (Some cleaners may leave a residue that will
prevent good adhesion on a recoat.) If recoating is
necessary, the owner should pay for it.
ORANGE PEEL
If the surface of the finish has a texture that
resembles an or- orange peel, the problem may have been
caused by rolling a finish, which then dries too
quickly. When that happens, the texture is "frozen" into
place before the finish has a chance to flow out and
level. The solution is to screen and re-coat.
PEELING, BUBBLES, BLISTERS AND
FISH-EYES
Any of these conditions can mean that the floor was not
sufficiently screened between coats of finish, or that
soap or some other contaminant substance was not removed
before coating. It's also possible that the affected
coat is incompatible with the finish or stain previously
applied, or a contaminated applicator may be
responsible. Problems in the top-most finish coat can be
screened and re-coated, although severe problems may
require complete sanding and refinishing.
ROUGHNESS
The cause is often contamination of the finish during
dry time, although moisture beneath the floor can also
cause the wood grain to rise. If a moisture problem is
evident, this must be corrected before re-screening and
re-coating.
STAINS
Spilled water and other liquids, including the residue
from incompatible cleaners, can stain finish. Cloudy
surface finish can be fixed by lightly rubbing with a
proper cleaner and buffing, although some stains require
screening and recoating. Strong chemicals should not be
used to remove stains.
STICKY BOARD SYNDROME
This occurs when excessive tannic acid in the wood
prevents the finish from adhering to the wood. This is
most common with oil modified finishes and with white
oak. When one board or several boards scattered
throughout the floor will not take stain or finish, the
only solution is to repair the floor by replacing the
boards.
UNEVEN GLOSS OR SHEEN LEVELS
Insufficient stirring of finish prior to application, a
contaminated finish applicator and uneven sanding or
finish thickness are typical culprits. All require
rescreening an re-coating. Great care should be take if
using different sheen levels. Sometimes, multiple coats
of satin, three or more coats will start to give a
hazing look to the finish coat.