company tower banner
Durock Alfacing International Company Logo

Durock Alfacing International PREP COAT

PREP COAT is 100% acrylic emulsion that is field-mixed with Portland Cement. It is a trowel-applied high performance coating for use on DuROCK PUCCS and InsulROCK Systems as a non-combustible base coat and adhesive. Prep Coat 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, breathable to water vapor and non-combustible. It is a convenient product since it requires only water to be added on site. This is a non-combustible material.

Product Type: Base Coat

Application Area: Stucco

Compatible Substrates & Surfaces: Concrete, Masonry

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

Application Method: Trowel

Chemical Family: Acrylics & Acrylates

  • TypeDocument Name
View All Documents

Knowde Enhanced TDS

Identification & Functionality

Chemical Family
Product Type

Features & Benefits

Applications & Uses

Application Area
Application Method
Compatible Substrates & Surfaces
Applications & Coverage
  • Apply Prep Coat 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 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 has dried.
  • Do not apply Prep Coat 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 (Dry Weight)20.0%-
Adhesive Bond Strengthmin. 0.3MPa-

Packaging & Availability

Packaging & Availability

Prep Coat is available in 19 L (5 gallon US) pails, yielding approximately 15.5 m 2 (165 ft 2 ) 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 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 be permitted to freeze.
  • Using a stainless steel or corrosion resistant mixing blade and power drill, mix one-half pail of Prep Coat with 15.0 kg (33 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 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.