Sika® Black Jack®-902 Bitumen & Flashing Primer
Sika® Black Jack®-902 Bitumen & Flashing Primer is a thin, fast-drying black primer designed to prepare surfaces before the application of bitumen paints, protective roof coatings and self-adhesive flashing tape. It creates a consistent key between the substrate and the covering product, helping the subsequent bituminous material achieve reliable contact with a properly prepared surface.
Suitable for professional building, roofing and property maintenance work, this versatile primer can be applied to numerous common construction materials. These include concrete roofs and floors, cementitious screeds and renders, bitumen felt, asphalt, mastic, wood and weathered corrugated iron or steel. It is also suitable for priming surfaces before the installation of Sika Black Jack Flashing Tape.
The ready-to-use formulation does not require thinning and can be applied by brush or suitable spray equipment. Its thin consistency allows the primer to penetrate porous surfaces and cover prepared non-porous materials with a light, even film. Once dry, it leaves a black primed surface ready to receive a compatible bituminous coating or flashing product.
Creates a Key for Bituminous Coatings
Bitumen paints and roof coatings perform best when they are applied to a sound, clean and suitably prepared substrate. Dust, surface porosity and inconsistent absorption can make it more difficult for the coating to establish uniform contact with the background.
Sika Black Jack 902 is formulated to prepare the substrate and create a suitable key for the following bituminous material. This makes it useful for new construction, roofing repairs, refurbishment and general property maintenance where a bitumen-based paint, coating or sealing system is specified.
The primer can be used with all bituminous surface coatings, providing a dependable preparation layer for a variety of roofing and construction applications. It is a preparatory product rather than a standalone waterproof coating and should therefore be covered with the appropriate compatible finishing system.
Ideal for Flashing Tape Preparation
Sika Black Jack 902 Bitumen & Flashing Primer is particularly useful when preparing porous, dusty or weathered substrates before applying Sika Black Jack Flashing Tape. Self-adhesive flashing products require close contact with the supporting surface, so effective preparation is essential.
Applying the primer helps consolidate the prepared surface and provides a more suitable background for the adhesive layer of the flashing tape. This can be especially valuable on masonry, concrete, timber and weathered metal, where the untreated surface may otherwise be dusty, absorbent or difficult to bond to consistently.
The primer must be completely dry before flashing tape is installed. Applying the tape while the primer remains wet or tacky could affect the bond and prevent the system from performing as intended. Always follow the separate application instructions supplied with the flashing tape.
Suitable Surfaces and Applications
Sika Black Jack 902 can be used to prime a broad selection of construction materials, including:
- Concrete roofs and floors
- Cementitious screeds and renders
- Bitumen roofing felt
- Asphalt and mastic surfaces
- Timber and wood
- Weathered corrugated iron
- Weathered steel surfaces
- Substrates being prepared for Sika Black Jack Flashing Tape
- Surfaces requiring preparation before compatible bitumen paints or roof coatings
The background must be sound, clean and free from standing water, frost, dust, oil, grease and other contaminants that could interfere with adhesion. Metal surfaces should be appropriately prepared, and loose rust or failing existing coatings should be removed before priming.
This product is not an anti-corrosion treatment. Where corrosion protection is required, the surface may need a suitable specialist system before the bituminous product is applied.
Ready-to-Use Application
Sika Black Jack 902 Bitumen & Flashing Primer is supplied ready to use and must not be thinned. Stir the contents thoroughly before application and continue stirring periodically during use to maintain a consistent product.
Apply the primer by brush or suitable spray equipment. When brushing, work the liquid well into the surface and aim to produce a thin, even covering without excessive build-up. On fibre-cement or rag felt, the product should be applied more generously to help saturate the absorbent material.
When applying by spray, avoid ponding or pooling. Heavy areas will take longer to dry and may prevent the primer from forming the consistent thin film required for the next product. Good application control is therefore important, particularly on smooth or non-porous substrates.
Apply at temperatures between +5°C and +30°C. Do not use on frozen surfaces, where rain is expected before the primer has dried or in conditions that prevent safe evaporation of the solvent.
Drying Time and Coverage
The primer normally dries in approximately three to six hours, depending on the temperature, ventilation, film thickness and porosity of the background. Cool, damp or poorly ventilated conditions may increase the drying time. Always confirm that the primer is fully dry before applying the next coating or installing flashing tape.
Approximate coverage varies according to the surface:
- Porous surfaces: Approximately 4–6m² per litre
- Non-porous surfaces: Approximately 11m² per litre
At a coverage rate of approximately 11m² per litre, the primer produces a wet film thickness of around 0.1mm and a dry film thickness of approximately 0.05mm. Actual consumption will vary depending on surface texture, porosity, application method and site conditions.
Key Benefits
- Creates a suitable key for bitumen paints and roof coatings
- Suitable for use before applying Sika Black Jack Flashing Tape
- Compatible with all bituminous surface coatings
- Fast-drying formulation
- Ready to use without thinning
- Can be applied by brush or suitable spray equipment
- Suitable for porous and non-porous substrates
- Works on concrete, cementitious surfaces, felt, asphalt, mastic, wood and weathered metal
- Ideal for roofing, construction, repair and maintenance projects
- Available in convenient trade sizes
Product Information
- Brand: Sika Black Jack
- Product: 902 Bitumen & Flashing Primer
- Product type: Bituminous coating and flashing primer
- Colour: Black
- Base: Solvent-based
- Application: Brush or suitable spray equipment
- Application temperature: +5°C to +30°C
- Typical drying time: Approximately 3–6 hours
- Coverage on porous surfaces: Approximately 4–6m² per litre
- Coverage on non-porous surfaces: Approximately 11m² per litre
- Available sizes: 1 litre and 5 litres
Cleaning and Safety
Clean tools immediately after use with Sika Wonder Wipes or white spirit. Remove spillages before the primer sets, as dried material can be difficult to remove.
Sika Black Jack 902 is a solvent-based product and must be used with appropriate care. Keep it away from flames, sparks, heat and other ignition sources. Do not smoke during application. Ensure good ventilation, avoid breathing vapours and wear suitable protective gloves and eye protection.
Always read the container label, safety data sheet and current product data sheet before use. Proper surface preparation, safe application and adequate drying are essential to achieving a dependable base for the selected bitumen coating or flashing system.
