Everbuild 903 1 Litre Black Jack Bitumen Trowel Mastic 486987 - 90301

Everbuild 903 Black Jack Fibre Reinforced Trowel Repair Mastic 1 Litre 90301

Barcode: 5029347009311

Sika Code: 486987

MPN: 90301

Colour: Black

Size: 1 Litre

Product Overview:

The Everbuild 903 Black Jack Fibre Reinforced Trowel Mastic is a professional-grade, fibre-filled bituminous repair compound designed for sealing, waterproofing, and repairing cracks, joints, and holes in roofs and building surfaces. Supplied in a 1-litre tin, this heavy-duty, trowel-applied mastic provides a tough, flexible, and weatherproof finish ideal for both trade professionals and DIY users.

The thick, fibre-reinforced formula ensures long-lasting durability and flexibility, even in harsh conditions. Suitable for use on roofing felt, mastic asphalt, corrugated iron, cast iron, fibre cement, lead, copper, zinc, concrete, and timber, this mastic remains soft beneath the surface skin to allow for movement without cracking.

Key Features and Benefits

• Fibre Reinforced Formula: Strengthened with fibres to increase durability and resistance to cracking.

• Trowel-Grade Consistency: Thick, easy-to-apply paste ideal for sealing joints, cracks, and roof penetrations.

• Waterproof and Weatherproof: Creates a watertight barrier, protecting surfaces from rain and frost.

• Excellent Adhesion: Bonds to a wide range of materials including metal, concrete, and roofing felt.

• Flexible Finish: The outer layer cures to form a skin, while the inner mass remains soft to accommodate movement.

• Ready to Use: No mixing required – simply open the tin and apply with a trowel or spatula.

• UV and Temperature Resistant: Maintains performance in extreme sunlight and cold conditions.

Applications

• Patching holes and cracks in roofs, gutters, and downpipes.

• Sealing joints in corrugated iron, fibre cement, or mastic asphalt roofs.

• Filling gaps in roofing felt, lead flashings, or chimney bases.

• Waterproofing junctions and problem roof areas.

• Bedding, bonding, and sealing applications on bituminous surfaces.

How to Use

1. Surface Preparation: Ensure the area is clean, dry, and free from grease, dust, rust, or debris.

2. Application: Apply directly from the tin using a trowel or putty knife. Press firmly into cracks or joints.

3. Finishing: Smooth the surface to create a 3 mm thick layer extending 25 mm beyond the crack on each side.

4. For Large Gaps: Embed a woven glass fibre membrane into the first layer and overlap by 50 mm. Apply a second coat after drying to fully cover the reinforcement.

5. For Metal Roofs or Sheets: Prime the area first with a suitable bitumen primer before applying mastic.

6. Curing: Allow 6–8 hours for surface drying and 24–48 hours for full cure depending on temperature and humidity.

Technical Details

• Product Type: Fibre-reinforced bituminous repair mastic

• Size: 1 Litre Tin

• Coverage: Approximately 0.5 m² per litre (depending on thickness)

• Drying Time: Touch-dry in 6–8 hours; fully cured in 24–48 hours

• Application Tools: Steel trowel or putty knife

• Finish: Flexible, black waterproof coating

FAQs – Everbuild 903 Black Jack Fibre Reinforced Trowel Repair Mastic

• What is it used for?
  For sealing and repairing cracks, joints, and holes in roofs, gutters, flashings, and pipe joints.

• Can it be applied to wet surfaces?
  Surfaces must be dry and clean for best adhesion and long-term durability.

• Does it remain flexible after curing?
  Yes. It retains flexibility to accommodate minor movements in the substrate.

• Is it suitable for large repairs?
  Yes. Use with reinforcing fabric for larger cracks or holes before applying a second coat.

• Can it be painted over?
  Painting is not recommended as most coatings will not adhere to bitumen.

• How long does it last?
  When applied correctly, it provides long-term waterproofing and protection, even in harsh conditions.

• What tools do I need?
  Apply using a steel trowel, spatula, or putty knife.

• Is it suitable for both metal and concrete?
  Yes. It adheres strongly to most common building materials, including metals, concrete, and asphalt.

Why Choose Everbuild 903 Black Jack Trowel Mastic?
This reliable trowel-grade compound is the go-to repair solution for professional roofers, contractors, and maintenance teams. Its thick, fibre-reinforced bitumen formula delivers excellent adhesion and flexibility, providing a long-term waterproof barrier on a variety of surfaces. Ideal for emergency repairs and general maintenance, Everbuild 903 ensures a durable, leak-proof finish in all weather conditions.

Always Read the Official Technical Data sheet prior to use to make sure you have all the details are correct and that there have not been any changes to instructions.

(Please note that tins will get dented in transit and this is not a reason for return please do not purchase tined products if this is an issue for yourself.)