Cementone All Weather Bitumen Mastic – 5L | Flexible Waterproof Roofing Sealant by Bostik
The Cementone All Weather Bitumen Mastic from Bostik is a high-performance, trowel-grade bituminous sealant, perfect for a wide range of roofing and waterproofing applications. Supplied in a 5-litre pack, this versatile black mastic is designed to bond and seal across a variety of materials, including mastic asphalt, roofing felt, corrugated iron, cast iron, fiber cement, concrete, lead, timber, and more.
Formulated to stay soft and pliable over time, this bitumen mastic develops a durable surface skin while maintaining flexibility underneath—allowing for moderate movement and long-term protection. It also contains reinforcing fibers for added strength and performance, making it ideal for pointing, bedding, sealing, and filling on both new installations and repair jobs.
Whether you're tackling leaks, sealing gaps, or weatherproofing exposed areas, Cementone All Weather Mastic offers a reliable, weather-resistant seal that performs in even the toughest outdoor conditions.
Features & Benefits
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Multi-purpose bituminous compound – trowel-applied for ease of use
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Ideal for waterproofing, stopping, sealing, bedding, and pointing
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Suitable for use on metal, concrete, timber, roofing felt, and more
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Forms a flexible, waterproof seal while remaining soft underneath
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Designed for all weather conditions – resists cracking and shrinking
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Reinforced with added fibers for greater strength and stability
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Perfect for sealing gutters, downpipes, joints, and roofing overlaps
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Size: 5 Litres – ready to use, no mixing required
Product Specifications
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Brand: Bostik
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Range: Cementone
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Product Type: Roofing Chemical / Bitumen Mastic
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Manufacturer Code: 30811916
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Colour: Black
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Pack Size: 5 Litres
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Weight: 7.44 kg
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Height: 233mm
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Width: 179mm
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Length: 179mm
Ideal For:
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Waterproofing flat roofs, joints, and flashings
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Sealing around gutters, vents, downpipes, and skylights
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Bedding and pointing roofing felt, tiles, and corrugated sheets
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Filling gaps and cracks in roofing, metalwork, and masonry
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Use in domestic, commercial, and industrial roofing projects
Why Choose Cementone All Weather Bitumen Mastic?
Trusted by professionals across the building trade, Cementone All Weather Mastic is a go-to solution for waterproofing and roofing that delivers long-lasting flexibility, adhesion, and protection. Whether you're working in dry or damp conditions, its advanced formulation ensures your repairs or installations hold strong, season after season.