Contractors may encounter a variety of problems 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 you the consumer, if these problems occur, it can help you understand the procedures involved in having the problem corrected. This page addresses what the problem is, the cause and the cure.

Here's a quick and easy checklist to identify and solve problems related to wood floor finishes:

Alligatoring
What it is: 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.

Causes: 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,  the use of thinners that cause the finish to dry too quickly, or application of oil-modified finish over waterborne finish or vice versa when the finish is not completely cured.

Cure: Screen and recoat after the finish has dried sufficiently.

Application Streaks
What it is: After the floor dries, marks still are visible from the path of the applicator. This condition is usually associated more with water-based finishes than other types of finishes, although it may effect other ,types as well.

Causes :It often occurs when  using an applicator that has hardened spots, 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 or applying finish in directly sunlit areas areas or other areas that are hot

Cure: Screen and recoat after the finish has dried sufficiently.

Bleed-Back
What it is: Occurs when excess stain seeps up from the grain or from spaces between boards

Causes: Excessive 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. Excessive heat during application or knots and areas that contain a higher amounts of sap.

Cure: 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.

Bubbles
What it is: Dried bubbles are visible on the surface of the finish

Cause: Soap or some other contaminant was not removed before coating, applying hot oil-modified finish onto a cold floor, applying finish to a hot floor, overworking finish during application, air movement across the floor that dries bubbles in place before they can flow out.

Cure: Problems in the top most finish coat can be screened and recoated, while cases of delamination require complete sanding and refinishing. Cover windows during the application to prevent hot spots on the floor

Discoloration
What it is
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.

Chipping
What it is: Dried finish separates from the surface in the form of flakes or chips.

Cause:  Applying a less elastic finish on top of a more elastic one' improper adhesion between coats, , spot contamination.

Cure: Screen and recoat. More than one coat may be needed, or problem areas may be spot-coated before
screening and recoating the entire floor.

Cloudy Finish
What it Is:  The finish appears cloudy or milky.

Cause:  Applying finish over a coat that isn't dry,

Cure:  Screen and recoat, being sure to increase the dry time between coats. Check with a damp rag before reapplication of finish to make sure the cloudiness has disappeared-if the finish appears clear when it is
dampened, the problem probably has been eliminated, and the floor is ready to be coated over.

Cratering
What it is: Often mistaken for bubbles, this problem resembles craters on the moon.

Cause: Contamination of the floor or finish,  application of finish over previous coats that are not dry or
have not gassed off.

Cure:  Sand the crater out by hand-sanding, and then screen, pad and recoat. Oftentimes, hand-sanding out the
craters will leave an unevenness in the floor. To eliminate low spots, spot finishing the areas may be necessary before the entire floor is recoated. If the problem is severe enough, the floor may need to be resanded. As a general rule, trowel-filling the floor may help prevent problems due to contaminants in the cracks between boards.  

Discoloration
What it is: The floor Changes color over time. Some areas may darken more than others.

Cause:  Oil-modified finishes amber in appearance and will yellow even further over time--this is to be expected.
wood lying in direct sunlight will change color over time--a natural change, wood also changes color through oxidation, a change that cannot be prevented.

Cure: Despite the pervasive myth that an oil-modified finish recoated with waterborne finish will stop ambering,
ambering of oil-modified finishes cannot be prevented. Shading the floor can minimize lightening. If marks are
left on the floor by area rugs or furniture, moving them around can equalize the change in color. Customers
should be informed that certain species, particularly cherry and many exotics, will change color greatly as
they age.
 

Excessive and Early Wear
What it is:  The appearance of too much wear on a relatively new finish.

Cause:  Improper maintenance procedures that may include failure to fully remove grit from the floor's surface, using water to clean the
floor, or using strong cleaners on the floor, pet nails and chair legs may contribute to the problem, not enough finish applied to the floor initially,  applying finish over coats that have not had enough time to gas-off and dry, improper sanding procedures--when the floor is left
too rough, finish accumulates in the bottoms of the grooves in the floor, leaving little coverage on the "peaks," where the finish then wears through. This may give the appearance of ridges in the flooring.

Cure: Institute proper maintenance procedures, including regular dust-mopping with an approved wood-floor cleaner, use of throw rugs and use of floor protectors. If improper sanding, then resand and recoat.

Fisheye / Crawling
What it is: A circular, cloudy haze with a clear center. They can measure up to about 1 inch in diameter.

Cause:  Contamination in the surface=the new coat "crawls" away from the wet or contaminated areas, giving the appearance of fisheyes when the finish sets.  If the finish container has sat undisturbed for some time and has not been properly agitated, a disproportionate amount of flow and leveling agents may be put on the floor, causing a fisheyed appearance.

Cure: Screen and recoat.

Iridescent Finish
What it  is: The finish dries with a metallic, colored cast to it.

Cause:  Inadequate ventilation during the drying of a coat of finish, causing solvent saturation in the air. The solvent then settles on the floor and is coated over.

Cure: Screen and recoat using proper ventilation

Orange Peel
What it is: The surface of the finish has a texture that resembles an orange peel.

Cause:  Rolling a finish that is not designed to be rolled on, causing it to illy too quickly. When that happens,
the texture is "frozen" into place before the finish has a chance to flow out and level, a finish or substrate that is too cold, use of an improper applicator that causes small bubbles to form in the finish. The bubbles then pop, leaving small dimples in the finish.

Cure: Screen and recoat.

Peeling,
What it is: The finish delaminates from the floor in sheets.

Cause:  Stain or previous finish coat that was not dry, skipping abrasion between finish coats, stain not sufficiently wiped up, improper tacking between coats,  surface contamination such as wax or oil-soap cleaners, or finishes that are not compatible.

Cure: Resand and recoat,

Pin Holes
What it is: Similar to fisheyes, but very, very small.

Cause:  A coat of finish being applied over a coat that was not dry.

Cure: Give the floor sufficient time to totally dry, then screen and recoat using correct dry times between coats.

Poly Beads
What it is: Poly beads are droplets ("BB's") of finish that form along strip edges. They can be soft and sticky when first formed, but will become quite hard if left undisturbed.

Cause: They are generally associated with a slow drying condition and excessive amount of sealer, stain and/or finish that seep into cracks.

Cure: Time will allow the floor to expand and contract, eventually allowing all of the undried finish to surface. When soft, the beads can be smeared, leaving an unsightly appearance that mat require screening and recoating. For hardened beads, the solution is to mechanically remove them with a sharp edge (i.e. razor blade) and if necessary, screen and recoat.  Do not attempt the screen hardened beads, as it will cause circular scratches within the finish.

Roughness / Grain Raise
What it is:  The surface of the wood floor is rough to the touch

Causes: Inadequate sanding, including skipping too many grits, contamination of the finish during dry time, not allowing sufficient dry time for waterborne sealers to flatten, moister causing the wood grain to rise, or not using enough coats of waterborne finish
Cure: If a moisture problem is evident, this must be corrected before rescreening and recoating.

Sidebonding / Panelization
What it is: The problems appear similar, but are different. With sidebonding, the bottoms of the edges of the individual
strips are "glued" together by the finish. It can occur with all types of finish, although it happens more frequently with water-based products. PANELIZATION occurs when the edges of boards are crushed and stick together as a result.

Cause:  Sidebonding results from the finish seeping down into the spaces between boards and gluing the bot­
toms together. Usually noticeable only after a drastic decrease in humidity.  Panelization occurs when the excessive moisture causes swelling of the floor and compression sets, in which the edges of the boards are crushed and stick together.  Staples that crack the tongue in some areas and not others can give the floor a panelized appearance.  In residential applications, a wet plywood subfloor that shrinks as it dries also can give the floor a panelized appearance.

Cure: Restoring normal humidity levels can return the floor to an acceptable appearance. If there still are gaps, see the "Cure" for "Gaps, Abnormal".  If those methods do not fix the floor, floor replacement may be necessary.
Staining floors can help prevent sidebonding. Consult your finish manufacturer for other preventive steps.

Stains
What it is:   Discoloration on area of the floor

Cause:  Spilled liquids,  pet stains, residue from improper cleaners, continual moisture leading to mildew (black). decay (brown/white) or alkaline conditions (white).

Cure: Cloudy surface finish can be fixed by lightly rubbing with a proper cleaner and buffing. although some stains require screening and recoating. Pet stains sometimes can be fixed by resanding, but frequently require total board replacement. One technique to eliminate pet stains is to apply naval gel (a phosphoric acid gel commonly available at hardware stores) to wick the tannins out of the area. This will not contaminate the floor for future finishing or leave a halo mark. as attempts at bleaching the floor often do.

Sticky Board Syndrome
What it is: The finish will not adhere or cure properly on one or more boards.

Cause:  Excessive tannic acid or pH imbalance in the wood. This is most common with oil-modified finishes and whiteoak., too much stain, and then finish. applied over very open grain.

Cure: When one board or several boards scattered throughout the floor will not take stain or finish. the most common solution is to repair the floor by replacing the boards. Or, boards may be taped off (using recommended tape) and scraped or handsanded, then coated with a water-based sealer. After proper dry time, they may then be coated with an oil-modified finish. Trowel filling may help prevent sticky board syndrome.

Uneven Gloss or Sheen Levels
What it is: The sheen of the finish is inconsistent.

Cause:  Insufficient mixing of finish prior to application,  Uneven sanding, uneven finish thickness, illusion caused by lighting, a contaminated finish applicator, such as a lanolinrich lambswool applicator that hasn't been thoroughly cleaned.

Cure: Screen and recoat. If lighting is the cause, discuss with the customer the reasonable inspection position for looking at a hardwood floor-from a standing position under normal lighting conditions.