Floor Preparation
Temperature
and Humidity
The environment in which the carpet is to be installed must
be controlled with the temperature between 65o
F and 95o F (18o C and 35o C)
and the relative humidity between 10% and 65%. If installing over
concrete, the slab temperature should not be less than 65o
F (18o C). These conditions must be maintained for
at least 48 hours before, during, and 48 hours after the installation.
Floor
Preparation
Each subfloor shall be inspected to determine the special care
required to make it a suitable foundation for carpet. All cracks
1/8 inch (3 mm) wide or protrusions over 1/32 inch (.8 mm) should
be filled or leveled.
Concrete
Concrete shall be cured, clean, and dry. If the carpet is to be
installed using an adhesive, the concrete shall be free of paint,
dirt, grease, oil, curing or parting agents, and other contaminants,
including sealers, that may interfere with the bonding of the
adhesive. Whenever a powdery or porous surface is encountered,
a primer compatible with the adhesive shall be used to provide
a suitable surface for the glue-down installation. Patching of
cracks and depressions shall be made with an appropriate and compatible
latex or polymer fortified patching compound. Do not exceed manufacturer's
recommendations for patch thickness. Large patched areas must
be primed.
Wood
Wood subfloors shall be structurally sound and have a minimum
18 inch (457 mm) air space underneath with cross ventilation.
Subflooring (plywood, hardwood, particleboard, oriented strandboard,
or other) must be flooring grade installed to the manufacturer's
specifications.
If the carpet
is to be installed using an adhesive, joints shall be filled,
and the subfloor surface shall be smooth and free of dirt, grease,
oil, wax, and other contaminants that may interfere with the bonding
of the adhesive. New and/or sanded wood floors shall be coated
with a compatible primer to provide an adequate bonding surface.
Patching of
cracks and depressions shall be made with an appropriate and compatible
latex patching compound.
The suitability
of a painted wood surface can be checked by gluing down a two-foot
square of the carpet, using the selected adhesive. If, after approximately
72 hours, the bond is strong and the paint does not pull up with
the carpet, it is generally considered safe to proceed with the
installation. However, installing over a painted subfloor may
void all applicable warranties. Glossy surfaces should always
be roughened prior to installation.
Pressure-treated
Wood
Chemically treated under pressure to alter its physical properties
in regard to outdoor exposure or flame retardancy, this material
may not be suitable for use as substrate upon which carpet is
to be installed using an adhesive. While some installations may
appear to be successful, floor covering adhesives could be subject
to chemical degradation when applied to these surfaces.
Installations
performed over pressure-treated wood may void all applicable warranties.
Metal
Metal floors must be level and cleaned of grease, oil, dirt, and
rust.
Resilient
Floor Coverings
Carpet should not be glued down directly over existing sheet vinyl,
homogeneous or laminated solid vinyl tile, and some rubber flooring
products. These materials may contain vinyl plasticizers, which
could migrate into the carpet adhesive and loosen the bond. Consult
individual manufacturers for specific recommendations.
Direct glue-down
over vinyl asbestos tile (VAT) and/or vinyl composition tile (VCT)
is acceptable as long as it is tightly adhered to the substrate
and all waxes, sealers, floor finishes, and other foreign materials
have been removed.
Note:
The installation of a second layer of finish flooring material,
including some carpets, can trap moisture, resulting in widespread
failure, even over subfloors that had never previously shown any
signs of moisture. Appropriate moisture tests should be performed
before installing over any existing resilient tile.
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CAUTION:
Some
sheet vinyls, resilient tile, and cut-back asphaltic adhesives
may contain asbestos. Unless absolutely positive beyond
any doubt that the floor is a non-asbestos product, assume
it contains asbestos, and treat it in a manner prescribed
for a floor containing asbestos. Recommended work practices
prohibit sanding, dry scraping, bead-blasting, or mechanically
pulverizing resilient flooring, backing, or lining felt.
Do not use power devices that create asbestos dust in removing
cut-back asphaltic adhesives. Various federal, state, and
local government agencies have regulations covering the
removal of asbestos containing materials.
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Terrazzo, Ceramic, Marble, Slate and other Nonporous Surfaces
If carpet is glued down over these surfaces, strict attention
must be given to the "open time" recommendations of the adhesive
manufacturer. All grout lines should be filled and leveled.
Carpet
over Carpet
In the absence of manufacturer’s specific recommendations
to the contrary, carpet should not be installed over existing
carpet.
Radiant
Heat
Heat must be lowered before installation to prevent floor adhesive
from "setting" too fast. When affixing tackless strips in stretch-in
installations, care must be taken not to nail into pipe or conduit.
Primers
The use of primers on floor surfaces is generally not necessary
except for sanded, dusty, porous, or acoustical surfaces. Priming
cannot overcome moisture conditions and must not be used for that
purpose. When used, primers must be thin and fast drying. They
must be compatible with adhesives, which should be applied only
after primer is dry.
Where lightweight
or acoustical concrete is used, refer to the manufacturer’s recommendations
for the proper primer to be used before carpet is installed.
Liquid Adhesive Removers
There are a number of liquid adhesive removers available that
will effectively remove cut-back or emulsion adhesive residue
from subfloors; however, there is evidence these products may
adversely affect the new adhesive or the new floor covering. Any
residual of these products left in or on the concrete slab is
capable of causing failure of the new floor adhesive. The use
of these removers may void all applicable warranties.
Testing of Concrete Subfloors Prior to Adhesive Installations
The owner or general contractor must submit to the flooring contractor
a written report on moisture and surface alkalinity of the slab
to determine its suitability as a substrate for the material to
be installed.
Moisture Testing
Concrete floors, even with adequate curing time, can present
an unacceptable moisture condition by allowing excessive amounts
of moisture vapor to pass through to the surface. This can be
a problem even on suspended concrete floors. All concrete floors
should be tested for moisture emission rate by utilizing an
anhydrous calcium chloride moisture test kit available from
installation supplies and accessories distributors.
This quantitative
method is very precise and must be conducted carefully with
strict attention to the test kit manufacturer’s detailed instructions.
Moisture emission rate is expressed in lbs./1000 square feet/24
hours. Because the calcium chloride test for emission rate requires
3 days to conduct, proper installation planning is a must. As
a general guideline, an emission rate of 3 lbs. (1.4 kg) or
less is acceptable for most carpet. In the range from 3 to 5
lbs. (1.4 to 2.3 kg), carpet with porous backings can usually
be installed successfully; however, the risk of moisture related
problems increases. Since some floor covering products are less
tolerant of moisture than others, always consult the individual
manufacturer to determine the acceptable emission rate for specific
products.
Alkalinity
Testing
A pH range of 5-9 is satisfactory; however, a reading above
9 requires corrective measures. Consult the adhesive manufacturer
for recommended testing and corrective procedures.
Relax Carpet
To minimize wrinkling and buckling, carpet should be unrolled,
allowed to relax, and ventilated with the induction of fresh air
for a minimum of 24 hours.
Ventilation
Conditions
For long term acceptable indoor air quality, it is recommended
fresh air ventilation in commercial spaces be maintained in accordance
with current guidelines of ASHRAE standard 62 published by American
Society of Heating, Refrigerating and Air Conditioning Engineers.
During installation,
fresh air ventilation should be maintained by utilizing exhaust
fans, and by operating the ventilation system at full capacity.
Always exhaust to the outside and avoid recirculation of air.
After installation,
maintain fresh air ventilation for 48-72 hours at normal room
temperatures by operating ventilation or exhaust fan system at
full capacity. Open doors and windows, if possible. These procedures
will help exhaust, dissipate, and eliminate lingering odors from
the installation.
