Page 87 - Industrial Coatings
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Before the material is applied, the substrate must be clean grading which does not reference APA markings may not be
and free of dust or foreign material. Paint, grease and oil a suitable grade.
must be removed either by grinding or sandblasting and
concrete surfaces must be shotblasted or water blasted. No liability is assumed by Polycoat Products for defects in
Control joints should be cut per standard concrete construc- the substrate.
tion practices and caulked.
PROTECTION OF WORK
Concrete must exhibit 3000-psi minimum. Concrete sur- While work is underway and for 72 hours thereafter, traffic
faces to be coated must be trowel finished in compliance from other trades should be stopped.
with the American Concrete Institute (except that hand trow-
eling is not required), followed by a fine hair brooming, left Material should be stored on plywood or non-asphaltic in-
free of loose particles, and shall be without ridges, projec- sulation board.
tions, voids and concrete droppings that would be mechani-
cally detrimental to coating application or function. Adjacent surfaces which are not to be coated, such as walls,
thresholds, fascias, etc., should be carefully masked before
New and Old Concrete: priming and coating. Mask vertical surfaces at the line
Refer to SSPC-SP13/NACE 6, or ICRI 03732: CSP 3-5. New detailed in the architectural drawings or, if none is shown,
concrete must be cured for 28 days prior to product applica- mask 4" or more up from the deck. When coatings are ap-
tion. Surface must be clean, dry, sound and offer sufficient plied by spray, caution is necessary, particularly during windy
profile for product adhesion. Remove all dust, dirt, oil, form weather, to prevent overspray damage.
release agents, curing compounds, salts, efflorescence,
laitance and other foreign matter by shotblasting and/or SECTION 3: PRIMING
suitable chemical means, in accordance with local chemical
regulations. Rinse thoroughly, to achieve a pH between 8.0 Polycoat Products elastomeric coatings frequently require a
and 11.0. Allow to dry completely. If old concrete has a surface primer. The preferred primer varies with the substrate as
that has deteriorated to an unacceptably rough surface, described below. Guide specifications state primer require-
Polycoat Products PC-260 or a mixture of Polyprime 21 and ments. Product data sheets contain application instructions.
sand should be used as a repair agent for cracks, spalls, bug
holes and voids. Upon full cure of the repair agent, prime the CONCRETE
entire surface intended for coating. Sealing Concrete: Most concrete has surface porosity, al-
Concrete Surface Preparation Reference: though it is seldom visible. This porosity develops at the
ASTM D4258 - Standard practice for cleaning concrete time of placement from various causes including water con-
ASTM D4259 - Standard practice for abrading concrete tent, drying rate, aggregate type and troweling action. When
ASTM D4260 - Standard practice for etching concrete elastomeric coatings are placed over concrete, there is a
ASTM F1869 - Standard test method for measuring moisture risk that blisters will form from outgassing through surface
pores. This risk is minimized by the use of a primer system.
vapor emission rate of concrete
ICRI 03732 - Concrete surface preparation Polyprime should be applied on all concrete and dense ag-
gregate structural concrete.
Neat cement sacking is not an acceptable surface prepa-
ration for coatings. Prime entire deck surface and all vertical or sloping sur-
faces of curbs, cants, parapets, etc., which are to receive
Plywood: Plywood should be new or cleaned and sanded. coatings, with one coat of Polyprime applied by roller or spray.
Plywood must be exterior grade plywood, having either The coverage rate is about 3 gallons per 100 square feet.
tongue-and-groove edges and ends perpendicular to sup-
ports. The plywood will be 19/32" or 21/32" thick. Allow polyurethane primers to dry for one hour or more be-
fore applying the base coat.
Plywood should be installed with a maximum of d" space
between the plywood sheets and laid over joists on 16" cen- Allow epoxy primers to dry until tack free before applying the
ters. Plywood sheets must be screwed down securely or base coat.
nailed with coated annular ring or screw shank nails.
Note: Surface temperature is more important than air tem-
If the underside of the joists is covered, the floor/ceiling cav- perature. The normal minimum surface temperature for ap-
ity must be vented to aid in drying and to minimize moisture plication is 50°F (10°C).
buildup in the deck structure.
WOOD
Damaged panels will be repaired/replaced before coating. Polycoat Products polyurethane coatings are self-priming
when applied to new wood construction (primer is not nec-
Old plywood must be cleaned and sanded before priming essary). For optimum adhesion on existing plywood, it is
with Polyprime at a rate of 3 gallon per 100 square feet prior advisable to use Polyprime.
to coating application.
STEEL
The only acceptable grade of plywood is APA rated, exterior Wire brush or sand steel surfaces until the metal is bright.
grade with exterior glue or better. Solvent wipe after cleaning.
Apply Polyprime at the rate of 3 gallon per 100 square feet.
The appearance and physical characteristics of the plywood Primer should be permitted to dry tack free before applying
and grade should be considered. subsequent coats. This ensures proper adhesion under
most conditions. Never apply Polyprime to wet or moist sur-
Note: The above plywood grade is called out in compliance faces.
with the American Plywood Association’s Standard. Plywood
14722 Spring Avenue  Santa Fe Springs, CA 90670-5108 USA  Tel: 562/802-8834  Fax: 562/921-7363  www.polycoatusa.com  Copyright March 2011 Polycoat Products
