CUPPING
CUPPING - CROWNING - BUCKLING
(see graphic)
"Washboard". Across the width of one piece of the
flooring material, the edges are high, the center is
lower. Generally develops gradually.
CAUSE:
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.
CURE:
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.
"CROWNING",
or the center of the piece of flooring (across its
width) is high, the edges are lower.
(see graphic)
CAUSE:
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.
CURE:
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
"BUCKLING",
"tented", "ballooning" floors. Pieces of the flooring
are no longer in contact with the substrate.
CAUSE:
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 floor contamination.
CURE:
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
CAUSE:
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).
CURE:
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.
CAUSE:
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.
CURE:
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 floor.
LOOSE,
NOISY, SQUEAKY FLOOR, NOISY, SQUEAKY FLOOR
CAUSE:
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,
excessive drying.
CURE:
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.
UNEVENNESS
CAUSE:
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.
CURE:
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.
CAUSE:
Consumer expectations, incorrect sampling, incorrect
ordering, mistake by supplier, manufacturer, installer
error (should not have installed).
CURE:
Pull and replace offending pieces. Review samples with
owner.
Excessive and Early wear on finish
- scratches, traffic pattern. Finish Peeling - bubbles,
blister - ROUGHNESS</
CAUSE:
Improper maintenance, grit, water, strong soaps, dog
toenails, chair legs.
CURE:
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,
blister
CAUSE:
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 soap maintenance.
CURE:
If de-lamination from wood surface, sand and refinish.
If surface only, screen and re-coat.
Pet
Stains
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 are
made.
Roughness
CAUSE:
Moisture from maintenance, spills, constant source,
condensation causing surface grain raise. Poor sanding,
edging, scraping. Contamination in finish during dry
time.
CURE:
Correct moisture source. Lightly sand or screen.
Re-coat.
Color
- not
right, changed
CAUSE:
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.
CURE:
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.
CAUSE:
High heels. Dropped heavy objects, metal tips on
furniture legs. Unprotected rolling of heavy appliances
such as refrigerator or freezer.
CURE:
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 and finish - owner pays.
Stains / discoloration
CAUSE:
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.
CURE:
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
Included are: Cigarette
burns
Chewing gum,
crayon, or candle wax
Dark spots and ink stains
Dried milk or food stains
Heel scuffs-Insects
Mold or mildew
Oil and grease stains
Scratches
Termites or
Insects
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 surface
finishes:
-
Cigarette burns:
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 repair.
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.
Scratches-Repair with 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
Insects-Termites
CAUSE:
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.
CURE:
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 repairs.
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.
SUBTERRANEAN TERMITE
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 pressure treated.
POST-CONSTRUCTION
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 SLAB CONSTRUCTION
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"
CAUSE:
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.
CURE:
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.