Page 8 - Polycoat 1.1 Table of Contents

SECTION 1.3
GENERAL GUIDELINES

CONTINUED

although it is seldom visible. This porosity develops at the occur, remove old coating before new coatings are applied.
time of placement from various causes including water Section 4: Expansion Joints
content, drying rate, aggregate type and troweling action.
When elastomeric coatings are placed over concrete, there is SEALING OF CRACKS, CONSTRUCTION JOINTS,
a risk that blisters will form from outgassing through surface SUBSTRATE CHANGES, AND FLASHINGS
pores. This risk is minimized when using a primer system. This step, which follows priming and precedes coating, is
the most critical stage in the application of Polycoat Products
Polyprime should be applied on all concrete and dense coatings. Success or failure in application of this system
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aggregate structural concrete. depends largely on how they are treated.
Prime entire deck surface and all vertical or sloping surfaces Working cracks in concrete are joints or cracks which have
of curbs, cants, parapets, etc., which are to receive coatings, moved or will move appreciably, in any or all of the three
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with one coat of Polyprime applied by roller or spray. The dimensions, due to thermal changes or vibration. A crack
coverage rate is about 1 gallon/200-300 sqft (0.14-0.20 liters/ which extends at each end to the edge of the surface, to a
sqm) or 200-300 sqft/gallon. building expansion joint or to another working crack may be
Allow polyurethane primers to dry for one hour or more before a working crack. A crack with minute broken fragments along
applying the base coat. the edge is probably a working crack.
Allow epoxy primers to dry until tack free before applying CONCRETE
the base coat. To prepare expansion joints, substrate changes, cracks and
flashings, apply backer rod if necessary then a polyurethane*
Note: Surface temperature is more important than air sealant and reinforcement tape, embedded into the sealant,
temperature. The normal minimum surface temperature for with a stripe coat centered over the crack. The crack must be
application is 50°F (10°C).
fully sealed. Any cracks over 1/16” (0.16 cm) shall be routed
WOOD to 1/4” x 1/4”(0.64cm x 0.65cm) prior to application of sealant
Polycoat Products polyurethane coatings are self-priming and reinforcing tape.
when applied to new wood construction (primer is not
necessary). For optimal adhesion on existing plywood, it is SUBSTRATE CHANGES
advisable to use Polyprime . Use caulking and reinforcement tape, with a stripe coat
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centered over the crack, backer rod and polyurethane* sealant
STEEL as required at changes in substrate material. Reinforcement
Wire brush or sand steel surfaces until the metal is bright. tape must be embedded into the sealant. It is also required
Solvent wipe after cleaning. when the substrate changes plane in a valley, or if a crack
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Apply Polyprime at the rate of at a rate of 1 gallon/200-300 sqft exists at other changes in plane.
(0.14-0.20 liters/sqm) or 200-300 sqft/gallon. Primer should be JOINTS IN PLYWOOD
permitted to dry tack free before applying subsequent coats. When a joint must be invisible at close range, filling voids and
Do not exceed recoat window of 12 hours after cure and if nail heads is necessary. Any wood-adhering, non-shrinking,
recoat window is passed then solvent wipe the surface with firm-setting, non-staining material is satisfactory. An epoxy/100
VOC-compliant solvent and re-prime before proceeding with mesh sand grout may also be used.
the next coat/phase.
To prepare plywood joints, flashings and substrate changes,
This ensures proper adhesion under most conditions. Never apply a polyurethane* sealant and reinforcement tape
apply Polyprime to wet or moist surfaces.
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embedded into the sealant with a stripe coat centered over
RECOATING SURFACES supported joints on the same plane, supported joints at
Decks to be re-coated should be thoroughly cleaned. When changes in plane, or unsupported joints.
the area intended for coating has completely dried and is free Defects in taping and flashing must be corrected prior to
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of dirt, dust, oil and other contaminants, apply Polyprime . proceeding with base coats.
If re-coat window has passed, then solvent wipe the surface
with VOC-compliant solvent and re-prime with Polyprime U. Section 5: Coating Application
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All coated surfaces require special attention. A test patch Polycoat Products materials are one or more components,
should be applied to check for bonding. If adhesion is good, liquid applied polyurethanes. When properly combined and
the surface is smooth, and no lifting occurs, apply coating as applied, they cure to form tough, high strength elastomeric
specified. If adhesion to substrate is poor, and lifting does membranes. All specified quantities are minimums and are on

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