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Durock Alfacing International PREP COAT PLUS

PREP COAT PLUS is 100% styrene acrylic emulsion that is field-mixed with Portland cement. It is a trowel-applied high performance coating for use on DuROCK PUCCS RMC and InsulROCK RMC Systems as a base coat and adhesive with enhanced flexibility and strength. Prep Coat Plus is a flexible and durable base coat that can also be used as a leveling coat for stucco, concrete and masonry substrates. It has excellent freeze-thaw stability, low water absorption, and breathable to water vapor. Prep Coat Plus can be applied as a high-build leveling coat, for added impact resistance on EIFS or to make a wall plumb and flat, applied up to 6.4 mm (¼ inch) thick in a single pass if required.

Product Type: Base Coat

Application Area: Stucco

Compatible Substrates & Surfaces: Concrete, Masonry

Features: Breathable, Combustion Resistant, Durable, Flexible, Freeze/Thaw Stability, High Performance, Impact Resistance, Low Water Absorption

Application Method: Trowel

Chemical Family: Acrylics & Acrylates

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Identification & Functionality

Chemical Family
Product Type

Features & Benefits

Applications & Uses

Application Area
Application Method
Compatible Substrates & Surfaces
Applications & Coverage
  • Apply Prep Coat Plus with a stainless steel trowel to achieve a minimum dry thickness of at least 2.0 mm (1 /12 inch) and embed DuROCK Fiber Mesh as per system specifications. This may require two passes, allowing the first coat to cure sufficiently to be dry and firm to the touch before application of the second coat. Applied as an adhesive, Prep Coat Plus shall be rendered with a notched trowel, conforming to the adhesive pattern delineated in the system specifications.
  • Substrate must be clean, dry, and free of cracks or loose material. Surface and ambient temperatures must be at least 4°C (40°F) a minimum of 24 hours, and must remain so until Prep Coat Plus has dried. Do not apply Prep Coat Plus in direct sunlight at temperatures exceeding 30°C (86°F) and protect from winds exceeding 25 km/hr (15 mph) as well as precipitation for at least 24 hours.

Properties

Soluble in
Water
Physical Properties
ValueUnitsTest Method / Conditions
Tack-Free Time2 - 3hours-
Typical Properties
ValueUnitsTest Method / Conditions
Water Absorption (min. 2 hours, 5 Pa Water Pressure)max. 20%-
Vapour Permeancemin. 320ng/Pasm²ASTM E96
Tensile Adhesion (After 2 Hours Drying, 48 hrs water immersion)min. 100kPa48 hrs water immersion followed by ASTM D1623
Tensile Adhesion (After 2 Hours Drying, 48 hrs water immersion)min. 300kPaASTM D1623

Packaging & Availability

Packaging & Availability

Prep Coat Plus is available in 19 L (4.18 gallons) pails (30kg/pail), yielding approximately 15.5 m2 (165 ft2 ) at 2.0 mm (1 /12 inch) dry thickness.

Storage & Handling

Pot Life
0.5 - 0.75 (hours)
Shelf Life
3 years
Storage & Mixing
  • Store Prep Coat Plus above 4°C (40°F) and below 40°C (104°F), off the ground and in a dry place away from direct sunlight. Employ temporary protection measures as needed. Under no circumstances shall Prep Coat Plus be permitted to freeze.
  • Using a stainless steel or corrosion resistant mixing blade and power drill, mix one-half pail of Prep Coat Plus with 10 kg (22 lbs) Type 10, 20 or 30 Portland Cement. Mix at 400 – 500 rpm, ensuring not to induce air into the product, until a uniform consistency is attained. Let the mixture stand for 5 minutes, then re-mix before use.
  • Up to 250 mL (8 oz) of potable water can be added to a full mix of Prep Coat Plus to adjust workability in hot temperature conditions. Accelerators and other additives are prohibited and will void warranty. Discard any material that has begun to stiffen.