Sika Black Jack 903 Fibre Reinforced Bitumen Trowel Mastic 2.5L 90302

Product Details: Brand: Sika | Range: Black Jack | Product Type: Fibre Reinforced Bitumen Trowel Mastic | Size: 2.5 Litre | Colour: Black | Product Code: 90302 | Model: 90302 | SKU: 852673 | MPN: 852673 | Sika Code: 852673 | EAN: 5029347009328 | Barcode: 5029347009328

Sika Black Jack 903 Fibre Reinforced Bitumen Trowel Mastic 2.5L is a ready-to-use black bituminous repair compound for roofing and external building repairs. It has a thick trowel-grade consistency, so it can be worked into damaged areas rather than brushed over like a coating.

This 2.5 litre tin sits between the compact 1L repair tin and the larger 5L trade size. It is a useful choice when one small tin may not be enough, but the job does not need a larger 5L container.

Made For Several Repair Points On One Job

The 2.5L size is best used when there are multiple small defects to repair across the same roof, gutter run or flashing area. It gives more working material for repeated trowel application while still being easier to handle and store than a larger tin.

• Multiple small holes, cracks or splits on suitable roof surfaces.
• Several gutter, pipe or downpipe joint repairs.
• Short seams, overlaps and roof edge details.
• Flashing edges, chimney bases and roof penetration areas.
• Small-to-medium repair patches on compatible materials.
• Roof maintenance jobs where a 1L tin may run out too quickly.

Why The 2.5L Size Makes Sense

Choose the 2.5L tin when the repair is not just one isolated crack. It gives enough product to move around several prepared areas without constantly worrying about running short, which makes it better for planned roof maintenance and grouped repair work.

For a single small patch, the 1L size is usually the neater choice. For larger areas, repeated trade use or broader patching work, the 5L size may be more suitable where available.

Key Benefits

• Mid-Range Tin Size: A practical option for several repair areas without choosing the largest tin.
• Fibre-Reinforced Compound: Designed to help strengthen local bitumen repair work.
• Trowel-Grade Consistency: Can be pressed into cracks, joints, gaps and holes.
• Ready To Use: No mixing required before application.
• Black Bitumen Finish: Suitable for compatible black bitumen roof repair work.
• Useful For Planned Maintenance: Good for moving between several prepared repair points.
• Compatible Surface Range: Suitable for many prepared roofing and building materials.
• Flexible Repair Use: Helps tolerate moderate movement after application.

Suitable Repair Areas

Sika Black Jack 903 can be used for patching, sealing, bedding, bonding and waterproofing on suitable prepared surfaces. It is commonly used around roofing felt, mastic asphalt, corrugated iron, cast iron, fibre cement, slates, lead, copper, zinc, concrete and timber.

• Roofing felt splits, holes and joint repairs.
• Mastic asphalt cracks and local damaged areas.
• Corrugated iron and fibre cement roof joints.
• Lead, copper and zinc flashing details.
• Concrete and timber areas where the surface is suitable and prepared.
• Gutters, downpipes, pipe joints and roof edge details.
• Chimney bases and roof penetration repair points.

How To Apply Across Several Repair Points

Always read the current Sika product data sheet and safety data sheet before use. The 2.5L tin is useful when working around more than one repair point, so prepare each area first before opening and applying the mastic.

• Plan the repair areas: Check each crack, joint, gutter detail or flashing edge and decide where the mastic needs to be applied.
• Clean each section: Remove loose grit, dirt, dust, rust, flaking coating and unstable material from every repair point.
• Check the surface condition: Make sure each area is dry, sound and suitable before applying the bitumen mastic.
• Apply by trowel: Use a steel trowel, spatula or putty knife to take material from the tin and work it into the damaged area.
• Build out the repair: Press the mastic into cracks, gaps, seams and holes, then spread it past the damaged edge to help form a sealed patch.
• Reinforce weaker areas: For larger openings, moving joints or weaker repair zones, use a suitable reinforcing membrane before applying a further layer.
• Let each repair settle: Allow the applied mastic to form its surface skin before further handling, coating or exposing the area to heavier use.

Choosing Between 1L, 2.5L And 5L

The 2.5L tin is the middle option in the 903 range. It is most useful when the job includes several small-to-medium repairs rather than one tiny patch or a larger trade maintenance area.

• Choose 1L: For one small crack, minor joint, small touch-in repair or very local patch.
• Choose 2.5L: For several repair points, repeated gutter details, grouped roof defects or small-to-medium maintenance work.
• Choose 5L: For larger repair areas, frequent use, broader patching and trade roof maintenance jobs.
• Use on dry surfaces only: The surface should be dry, clean and stable before application.
• Do not use as a structural repair: Broken, loose or unstable materials should be repaired correctly before applying mastic.
• Do not rely on standard paint over bitumen: Many coatings do not bond well to bitumen surfaces.

Technical Notes

• Black fibre-reinforced bituminous trowel mastic.
• 2.5 litre tin for grouped repair points and small-to-medium maintenance jobs.
• Applied by steel trowel, spatula or putty knife.
• Designed for sealing, waterproofing, bedding, bonding and patch repair use.
• Suitable for many clean, dry and prepared roofing or building surfaces.
• Approximate coverage depends on surface condition, repair depth and application thickness.
• Drying note: Sika advises that the mastic forms a surface skin after around 24 hours. The material underneath remains plastic for many months, which helps it tolerate moderate movement after application.

Products To Help With Preparation, Use Or Clean-Up

Before applying the mastic, each repair area should be cleaned back properly. A scraper, brush or wire brush can help remove loose material, surface dirt, rust, grit and unstable coating from the areas being repaired.

Porous, friable or difficult surfaces may need priming before the mastic is applied. Use Sika Black Jack 902 Bitumen and Flashing Primer 1L where a compatible bitumen primer is required.

For handling and clean-up after preparation or application, Sika Everbuild Heavy Duty Textured Wonder Wipes can help remove general grime, dirt and residue from hands, tools and suitable surfaces.

For a single small repair, choose the 1L Sika Black Jack 903 size from the side options. For larger roof repair work, choose the 5L size where available.

• Specification

  Weight	4 kg
  Range	Black Jack
  Manufacturer	Sika
  Reference Code	90302
  Reference Code sika	852673
  Type	Bitumen Trowel Repair Mastic
  Size	2.5 Litre

• Product FAQs

  Q: What is Sika Black Jack 903 2.5L used for?
  A: It is used for sealing and repairing several cracks, joints, holes, gutters, flashings, roof penetrations and local problem areas on suitable roof surfaces.
  Q: What size is this trowel mastic?
  A: This product is supplied in a 2.5 litre tin.
  Q: When should I choose the 2.5L size?
  A: Choose the 2.5L size for several repair points, repeated gutter details, small roof sections or medium maintenance work where a 1L tin may not be enough.
  Q: How is Sika Black Jack 903 applied?
  A: It is applied directly from the tin using a steel trowel, spatula or putty knife.
  Q: Can it be applied to wet surfaces?
  A: No. The surface should be clean, dry and free from grease, dust, rust, loose material and debris for best adhesion.
  Q: When should reinforcing fabric be used?
  A: Use reinforcing fabric for larger gaps, cracks, holes or weaker repair areas before applying a second coat.
  Q: How long does it take to dry?
  A: Sika states that the product takes around 24 hours to develop a surface skin, with the material below remaining plastic for many months.

• Downloads

  Sika Black Jack 903 Bitumen Trowel Mastic Technical Data Sheet
  Sika Black Jack 903 Bitumen Trowel Mastic Product Flyer
  Sika Black Jack 903 Bitumen Trowel Mastic Safety Data Sheet