QUICK FIND INDEX-FAQ's
- PROBLEMS, CAUSES and CURES
Abnormal Cracks *
Insects * Bubbles in Finish * Loose-Noisy Floors * Buckling * Color
* Peeling Finish * Cracks * Pet Stains * Creaking & Squeaky
Wood Floors * Crowning * Roughness in Finish * Cupping * Stains
* Dents * Squeaky Floors * Discoloration * Termites * First Aid-Surface
Finishes * Unevenness * Grading questions * Vacant house effect
CUPPING - CROWNING
"Washboard". Across the width of one piece of the flooring
material, the edges are high, the center is lower. Generally develops
Moisture imbalance through the thickness is the only cause. The
material was manufactured flat and was flat when installed. Job
site or occupant provided moisture is greater on the bottom of the
piece than on the top. Prove it with your moisture meter. Find the
source of moisture and eliminate it. Common moisture sources and
their corrections are:
Airborne (Relative Humidity) - dehumidify air space or (lack of
during heating season humidify air space); wet basement - ventilate,
dehumidify; crawlspace groundcover/vents, add exhaust fan on timer;
lot topography - french drain to remove; rain handling provisions
- correct to drain away from house; excessive lawn/garden moisture
- reduce/waterproof foundation; leaks plumbing, roof, doors - fix;
don't hose patio; maintenance; correct capillary through slab -
install barrier, french drain, drain tiles. In kitchens, the dishwasher
and ice maker are notorious leakers.
Expansion is also the result of site moisture and may have moved
the floor tight to vertical surfaces. If so, remove flooring along
the wall, or saw cut, to relieve pressure.
Allow time. Time for the corrections to take effect - to permit
the floor to improve on its own. It may become acceptable . After
stabilized, sand flat and finish. Cost of corrections should be
for owner or builder to cover.
or the center of the piece of flooring (across its width) is high,
the edges are lower.
While moisture imbalance might be the cause (by excessive moisture
introduced on the finish side of the floor; i.e. water used in maintenance,
plumbing leaks overhead sprinkler system), it is more likely that
the floor was cupped (problem #I) and sanded flat thus removing
the outer edges, the sanding having been done at the wrong time,
i.e., before corrections were made and before the floor flattened
on its own.
After the floor has stabilized following corrections, sand flat
and finish. Note: Some slight cup and/or crown can and should be
tolerated. It is common in wood floors, especially in wider planks.
It is, in many cases, seasonal in its occurrence and can be minimized
with lighting and furniture placement, by using beveled products
and by other than high gloss finish
"tented", "ballooning" floors. Pieces of the
flooring are no longer in contact with the substrate.
Generally an extreme moisture problem. See Problem #1 for sources
and corrections. Inadequate expansion space, even "net fit"
(installer error) prevents normal expansion. On nailed products,
insufficient nailing, incorrect nails, incorrect sub floor construction.
On glue down product, incorrect mastic, insufficient mastic, wrong
trowel used, inadequate mastic transfer, sub floor separation, sub
If caught early, spot repair/replacement may be possible. In many
cases, however, pull, correct, and relay/replace is more practical.
NORMAL CRACKS -SEPARATION
BETWEEN INDIVIDUAL FLOORING PIECES- ABNORMAL CRACKS - LOOSE, NOISY,
SQUEAKY FLOOR- UNEVENNESS
Mother Nature. Dryness. As moisture caused some earlier problems
1, the loss of moisture results in the most frequent reason for
shrinkage of individual pieces and cracks. Should a floor have been
exposed to problems 1, 2 & 3, then afterwards, "dried out",
cracks will develop. If subjected to extreme moisture, the edges
of the wood (a vegetable made up of cells), can crush, and subsequent
drying and shrinkage can present larger than normal cracks. Square
edge (un-beveled) floors show cracks more than beveled. White, light,
pastel finished show cracks more than darker wood-tone finished
floors. Most cracks are seasonal - they show in dry months, or the
cold season when heating is required, and close during humid periods.
This type of separation and closing is considered rm 1. In solid
2 1/4" wide strip oak floors, dry time cracks may be the width
of a dimes' thickness (1/32"). Wider boards will have wider
cracks (and the reverse is true).
Add moisture to the air space during dry periods. A constant Relative
Humidity (RH) of 50% works in concert with the manufacture of wood
floors to provide stability in the floor. Live with normal cracks
or add humidity - its 'the owners' choice. Easy ways - boil a pan
of water on the stove, turn off bathroom exhaust fan, open dishwasher
after rinse cycle, a pan of water in furnace fan compartment, hang
laundry to dry in basement. Better yet, install humidifier to furnace
controlled by a humidistat set at 50% RH. In dry and warm climates,
add moisture (pan or humidifier) and run furnace "fan only".
Abnormal cracks - larger
than normal, cluster or localized, end separation, not uniform and
not general throughout, do not close up during humid months.
Edge crush from prior exposure to extreme moisture, especially solid,
flat grain flooring (and may be general throughout). If surface
coated (such as polyurethane), edges of some adjacent pieces may
be literally "glued" together, or panelized, and shrinkage
cracks multiplied at the weakest points. (See note that follows)
"Hot Spots" in the undersurface such as poorly insulated
heating ducts, hot water plumbing lines, radiant heating system
(if so, should be laminated products only), the new "Instant
Hot Water" feature, register openings, heat from refrigerator
motor, check nail spacing with stud finder. With adhesive applied
floors, early foot traffic, incorrect adhesive, amount transferred
or used (most noticed in traffic pattern). 3/4" thick solid
parquet with no return control (cork) in expansion space, generally
indicated by center of the field is tight, with gaps around the
walls. Note if there is a pattern to the cracks, such as 4' X 4'
or 4' X 8' indicating sub floor change or weakness. Glued over sheet
vinyl may show 6' cracks from shrinkage or loose vinyl. Does the
pattern of cracks convey a relationship with foundation or slab
cracks and/or settlement. Check nail spacing on solid products take
wood moisture content reading and if it is within normal range for
your market and the wood is undersize, drying was improper prior
to manufacture. If wood MC is normal and wood is "on size"
or over, the wood was wet prior to installation.
In addition to obvious corrections suggested under it cause"
(i.e., add insulation between heat ducts and sub floor for "hot
spots", pull, add adhesive, relay, adjust 3/4 parquet, add
expansion joint control, add cross bracing under weak sub floor),
attempt to elevate the relative humidity in the air space and after
sufficient time has passed to confirm that the problem has stabilized,
fill the cracks with the appropriate color-matched fill. Re-coat
if necessary. Last resort, pull and replace - note however, that
if corrections are not made, chances are that replacement will develop
the same problem. Note: When a floor shows "panelizing"
and a surface coat has been used, you might choose to sand then
finish with seal and wax, or if surface finish is required, use
a sealer first rather than the stronger finish directly on the new
LOOSE, NOISY, SQUEAKY
FLOOR, NOISY, SQUEAKY FLOOR
Inadequate nailing, flexing weak sub floor system, nailed over particle
board type sub floor. Check sub floor thickness and joist direction.
Insufficient or incorrect adhesive. Subjected to excess moisture,
Add face nails, counter-sink&putty. Strengthen sub floor from
below. Inject adhesive or pull-add-relay. Lubricate squeaks with
graphite, wax, baby powder. Wedge sub floor up from joists.
Wood joist system - sub floor warped and loose, joists warped or
fractured, support pillars settled, perimeter foundation settlement.
Concrete slab system
- slab cracked and settled.
Correct, strengthen substructure, repair sub floor, splice joists,
add joists. Structural, failure is not the wood floor contractors
domain usually. Owner needs a general contractor for repairs prior
to wood floor corrections.
Quality or "Grade"-
knots, heavy color variation, out of-square, surface defects.
Consumer expectations, incorrect sampling, incorrect ordering, mistake
by supplier, manufacturer, installer error (should not have installed).
Pull and replace offending pieces. Review samples with owner.
Excessive and Early wear on finish - scratches, traffic pattern.
Finish Peeling - bubbles, blister - ROUGHNESS
Improper maintenance, grit, water, strong soaps, dog toenails, chair
Correct maintenance, especially vacuum, not just broom sweep. Clip
dog's nails, felt chair leg glides, appropriate exterior walk-off
mats to prevent grit, area rugs especially in front of kitchen sinks.
Re-coat if necessary - owner pays.
Finish Peeling - bubbles,
Stain not dry. Excessive burnishing. Early coats not dry. Skipped
screening between coats. Product incompatibility. Stain not sufficiently
wiped leaving heavy pigment on surface (is finish peeling from finish
or wood?), improper tack. Surface contaminated such as wax, oil
If de-lamination from wood surface, sand and refinish. If surface
only, screen and re-coat.
CAUSE: (We all know the cause !)
CURE: For the most part minor pet stains will lessen or get
lighter with sanding. Repeated stains (the darker the deeper is
the rule) will not sand out. Several consideration must be given.
1 - Will the floors be refinished ? If so, a light or medium colored
stain can be use to help "cover or lessen" the stains.
Sometimes a "painted" design on the floor will cover the
stains, or the use of area carpets over those stained areas. 2 -
Removal and repair will give BEST results, if time, and budget allowances
Moisture from maintenance, spills, constant source, condensation
causing surface grain raise. Poor sanding, edging, scraping. Contamination
in finish during dry time.
Correct moisture source. Lightly sand or screen. Re-coat.
Color - not right,
Customer expectation, poor sampling, lighting over the floor and
room colorings. In correct maintenance including residue of cleaners,
waxes, etc. (i.e., Oil Soap). Wood itself changes color with age
("Patina"). Extreme hot sunlight through South/West facing
windows. Color different under rugs or low furniture from lack of
exposure. Bleaching is unpredictable - don't oversell expected results.
Compare with sample. Explain lighting and colors. Remove residue
and correct maintenance procedures. Move rugs and colors will even
out in time. Shade large windows.
Dents - Yes, wood dents.
High heels. Dropped heavy objects, metal tips on furniture legs.
Unprotected rolling of heavy appliances such as refrigerator or
Remove high heels or maintain proper heel-tip protectors. Provide
large felt or rubber protectors under heavy furniture legs. Roll
heavy casters over plywood protection only. For individual dents
where wood fibers are not broken, cover with a dampened cloth and
press with an electric iron to draw fibers up. Last resort sand
Stains / discoloration
Water from spills, water from continual source leading to mildew
(black) or decay (brown/white) or alkali (white) or bleeding up
of adhesive. Urine (dark) from pets, wet diapers. Unprotected metal
chair legs. Improper maintenance with water or harsh chemicals.
Traffic pattern wear. Excessive harsh sunlight (wood looks starved
near South or West facing windows). Light deprivation under area
rugs, large low furniture. Be sure to observe if only one piece
of flooring is affected, or does the stain continue across adjacent
pieces. Oil soap residue.
Correct water source, let dry. Minimize sunlight. Relocate area
rugs. Correct maintenance procedures and products. Dark stains,
lightly abrade surface with fine sandpaper, feather out area, dampen
cloth with 50/50 household bleach & water and lay on stain for
30 minutes, remove, let dry, re-color if necessary. Waxed floors,
clean with renovator or paint thinner (combustible) and re-wax.
Whiteness/cloudy surface finish, clean and buff. If all fails, screen
and coat, sand and refinish, replace severe boards.
First Aide for Surface Finishes
burns-Dark spots and ink stains-Dried milk or food stains-Heel scuffs-Insects-Oil
and grease stains-ins-Scratches-Water stains or white spots-
How can scratches or
stains on wood flooring be repaired?
First aid for wood floors
depends on the type of surface. In the following chart, solutions
in the middle column are for floors finished with wax or penetrating
stains. Solutions in the right-hand column are for floors finished
with polyurethane or other surface finishes.
Remember when removing stains from any wood floor, always begin
at the outer edge of the stain and work toward the middle. Always
use the wood flooring manufacturer's cleaning, repair and finish
products when known. The following problems & cures are for
Most common burns can be treated with touch up kit (rub with steelwool
/ sandpaper, stain as needed, touchup finish). If the burn is deeper,
boards/pieces may have to be replaced & refinished, a wood floor
contractor is strongly suggested.
Chewing gum, crayon,
or candle wax-
Apply a plastic bag filled with ice on top of the deposit until
it is brittle enough to crumble off. Clean the area with a product
made for urethane finishes.
Dried milk or food stains-Heel
scuffs-Dark spots and ink stains--Oil and grease stains-Water stains
or white spots
Use a cleaner developed
specifically for urethane finishes. For stubborn spots, scrub using
the urethane cleaner and a scrub pad made for urethane floors.
High Heel Shoe Dents
-1/4 inch spike heels will cause dents that require professional
Mold or mildew - Use
a cleaner developed for urethane finishes. If the mold or mildew
lies underneath the surface finish, sand and refinish the area.
a touch-up kit for urethane finishes, available from any wood flooring
retailer. For small surface abrasions (scratch is white) a small
amount of "Endust" of a soft cloth, wiping with scratch
direction will bring back to floor original color
Identified by eating
corridors beneath surface which when weakened, the fragile surface
sags. The bugs are white or cream colored. Subterranean type build
sand tubes. Powder post Beetles identified by 1/ 16" diameter
perfect circle hole in surface of floor. Active infestation will
show clean bright wood in holes with fine talcum powder like dust
piles around the holes. Inactive holes are darkened, even show stain
or finish on walls of the hole. When in doubt, collect sample bugs,
consult exterminator, entomologist, or extension service, etc.
Structure must first be rid of active termites by professional exterminator.
Repair structural damage. Pull and replace damaged floorboards,
sand and refinish. Heavy infestation of powder post beetle, handle
as above. When powder post is occasional, few boards especially
in new floors, treat individual openings immediately with insecticide
(from hardware or garden shop) injected by syringe into holes, or
aerosol insect spray through a straw. Usually will not disturb finish.
Have owner watch for new evidence (dust piles) and treat again.
After 2-3 months holes may be filled. Termites will not be associated
with the flooring and costs will be the responsibility of the owner.
Powder post may be in new flooring materials. Immediately on first
report notify your floor supplier. Prompt action by all will minimize
costs involved. Check all surroundings for infected wood molding,
furniture (especially bamboo and antiques). If old infestation is
in other materials the owner must stand the costs involved in floor
Wood Damage by Termites:
Wood damaged by subterranean termites is often not noticed because
the exterior surface usually must be removed to see the damage.
However, galleries can be detected by tapping the wood every few
inches with the handle of a screwdriver. Damaged wood sounds hollow,
and the screwdriver may even break through into the galleries. Subterranean
termite feeding follows the grain of the wood and only the soft
springwood is attacked. Unlike dry wood termites or other wood boring
insects, subterranean termites do not push wood particles or pellets
(fecal material) to the outside, but rather use it in the construction
of their tunnels. This debris, along with sand and soil particles,
is used as a form of plaster.
PREVENTION AND CONTROL
The best control of subterranean termites is prevention. The best
time to provide protection against termites is during the planning
and construction of a building. Prevention should include: 1-Removal
of all stumps, roots, wood, and similar materials from the building
site before construction is begun. 2 -Removal of all form boards
and grade stakes used in construction. 3-There should be no contact
between the building woodwork and the soil or fill. Exterior woodwork
should be located a minimum of 6 inches above ground and beams in
crawl spaces at least 18 inches above ground to provide ample space
to make future inspections. 4- Ventilation openings in foundations
should be designed to prevent dead air pockets and of sufficient
size to assure frequent changes of air - at least 2 sq. ft. to 25
running feet of outside foundation wall. This helps keep the ground
dry and unfavorable for termites. 5- Thorough annual inspections
should be conducted to discover evidence of termite activity such
as shelter tubes on foundation surfaces, discarded wings or adult
termites. 6- Any wood that contacts the soil, such as fence posts,
poles and general foundation structures, should be commercially
TREATMENT OF STRUCTURES
Crawl Space Treatment Dig narrow trenches along both the inside
and outside of foundation walls and around piers and chimney bases,
and apply diluted spray as described above. Also be sure to trench
and treat around sewer pipes, conduits and all other structural
members in contact with the soil. Apply the insecticide to the trenches.
The insecticide must be applied to both the inside and outside of
the foundation and also around piers, chimney bases, pipes, conduits
and any other structures in contact with the soil. The trench should
be as deep as the top of the footing. Mix the insecticide with water
as recommended on the pesticide label. Apply the diluted spray at
the rate of 2 gal. per 5 linear feet of trench. Mix the insecticide
with the soil as it is being replaced.
Concrete Slab Construction
It is possible to trench around the outside of a slab after it has
been poured, as described above, but this alone usually will not
give satisfactory control because the termite colony may be entering
the structure from the soil under the slab. Homeowners are not equipped
to treat under slabs after the slab foundation is completed. A professional
pest control operator usually is needed to do sub-slab chemical
injections. Most subterranean termites feed along the grain of the
wood, eating the spring wood and leaving the summer wood. The Formosan
termite feeds on both and forms a hollow. In Hawaii, where unprotected
homes were built over large colonies, records show that the Formosan
subterranean termite caused major structural damage in 6 months
and almost complete destruction in 2 years (Tamashiro 1984). Moisture
Requirements The Formosan termite, like all subterranean termites,
uses the soil for a source of moisture. However, Formosan termite
colonies can obtain moisture from plumbing or roofing leaks.
INSPECTION OF CONCRETE
Inspect for evidence of termite activity near any plumbing that
goes through the slab. Look for tubes around baseboards. Tap baseboards
around walls. Check for wood which is in contact with the soil.
THE VACANT HOUSE - "Greenhouse Effect"
Security -conscious vacationers, a homebuilder's unsold inventory,
whenever a wood floor is deprived of an air flow in the environment,
it can and will misbehave. Sunlight through windows generates heat,
lowers humidity, moisture vapor enters to balance, nights cool off,
humidity builds and wood floors cup. Thermostats set at 60 degrees
and outside, winter howls, heating system runs constantly with no
moisture added, and floors shrink.
Avoid problems by leaving windows "ajar", have neighbor
air the house out occasionally. Treat floors as discussed under
cupped, tented, or shrinkage cracks and only after environment returns
to normal. Owner to pay.
The above commonly ask questions will help you and your wood floor
contractor resolve some of the everyday concerns about wood floors.
By no means is this a sure method or procedure. If in doubt, get
a second opinion.