BULLDOG/DUREX® #BC123 Elastomeric Base Coat

Elastomeric base coat products help build the foundation for a stronger roof coating system. BULLDOG/DUREX® #BC123 Elastomeric Coating is a waterborne, 100% acrylic base coat designed as the initial coat before applying BULLDOG/DUREX® TC101 Elastomeric Coating as the topcoat finish.

Built as the First Coat in the BULLDOG/DUREX System

BULLDOG/DUREX® BC123 is formulated with 100% acrylic resins to create a seamless, monolithic coating when cured. It provides durability, weatherability, elongation, moisture resistance, low-temperature flexibility, and resistance to ultraviolet radiation.

The base coat is the same formulated material as the TC101 topcoat but is provided in an alternate color, generally gray. That color difference helps applicators confirm proper coverage when the topcoat is applied. Simple idea, smart execution — because guessing coverage on a roof is not a strategy.

Recommended Uses

BULLDOG/DUREX® BC123 Elastomeric Coating is designed for use as a base coat or initial coat before BULLDOG/DUREX® TC101 Elastomeric Coating. It may be used on thoroughly prepared metal, modified membranes, asphalt, EPDM, Hypalon®, plywood, and masonry surfaces.

• Base coat for BULLDOG/DUREX® TC101 topcoat systems
• Prepared metal roof surfaces
• Prepared modified membrane surfaces
• Prepared asphalt roof surfaces
• EPDM surfaces with required primer
• Hypalon® surfaces
• Plywood surfaces
• Masonry surfaces

Surface Preparation

All surfaces must be thoroughly prepared before applying BULLDOG/DUREX® BC123. Clean the roof of loose dirt, debris, oil, and any contaminants that may interfere with adhesion. Power wash the surface as needed and allow it to dry before applying the base coat. Broom or blow off any remaining loose dirt or debris.

For metal surfaces, remove all loose rust and apply the applicable rust primer when necessary. For single-ply membranes, thoroughly power wash the roof to remove dirt. BULLDOG® #115 EPDM Rinseable Primer must be used on EPDM roofs before coating.

Remove any blisters and make repairs before coating. All loose gravel on gravel-surfaced roofs must be removed. Areas that pond water for 24 hours should be corrected by installing a drain or constructing slope to drain using accepted roofing practices.

Application Guidelines

Apply BULLDOG/DUREX® BC123 by roller, brush, or spray. Use the appropriate primer when required for the surface. Apply BC123 at a minimum rate of 1 gallon per 100 square feet when used as the base coat for a roof maintenance application.

Once the base coat cures, BULLDOG/DUREX® TC101 can be applied as the topcoat. The gray base coat helps applicators visually confirm that the finish coat has been applied with adequate coverage.

Application rates may vary depending on surface porosity and substrate irregularity. Rougher, more porous, or uneven surfaces may require additional material to achieve proper coverage.

Application Conditions

BULLDOG/DUREX® BC123 is a waterborne product and should not be applied below 50°F. Surface temperature at application should be between 50°F minimum and 95°F maximum.

Dry time depends on temperature, direct sunlight, air movement, relative humidity, dew point, and coating thickness. Under proper conditions, the coating will cure in approximately 2–4 hours. High humidity will slow dry time. Allow the base coat to thoroughly dry before applying successive coats.

Topcoat Timing

BULLDOG/DUREX® BC123 may be left exposed before topcoat application for no longer than three months. This gives applicators flexibility when weather, roof access, or site conditions delay the finish coat.

Performance Characteristics

BULLDOG/DUREX® BC123 is designed for high-performance roof coating systems. It has a weight of approximately 12.1 pounds per gallon, 66.9% solids by volume, 43.0% pigment volume concentration, 110 KU viscosity, and a pH of 8.6.

The product passes a 1/8-inch mandrel bend at -30°F under ASTM C-734. Elongation at break is listed at 245% at 74°F and 130% at 0°F under ASTM D-412. Tensile strength at break is listed at 165 psi at 74°F and 660 psi at 0°F under ASTM D-412.

Recovery after 25% elongation is 65%. Permeability at a 20 mil film is less than 20 perms under ASTM E96-80. Accelerated weathering shows no effect after 2 years in a weatherometer under ASTM G-53.

Application Equipment

For roller application, use medium or long nap rollers. For spray application, use airless spray equipment capable of 2500–3000 psi with an output of 2–2.5 gallons per minute. Recommended tip size is .027 to .041.

Important Use Limitations

Do not use BULLDOG/DUREX® BC123 on areas that pond water. Do not allow the product to freeze. Consult Palmer Asphalt Company for proper surface preparation and primer requirements before use.

Available Container Size

• 5-gallon pail

Cleanup

Clean tools with water. Because BULLDOG/DUREX® BC123 is waterborne, tools should be cleaned before the coating dries.

Why Choose BULLDOG/DUREX® BC123?

BULLDOG/DUREX® BC123 Elastomeric Base Coat gives contractors a 100% acrylic first coat designed to support BULLDOG/DUREX® TC101 topcoat applications. With strong elongation, UV resistance, moisture resistance, low-temperature flexibility, and a contrasting gray color that helps confirm topcoat coverage, BC123 is a smart base layer for roof maintenance coating systems.