Bostik Cementone Water Seal 5 Litre | 30812236

• Single-coat exterior water seal for masonry and wood
• Clear, breathable finish - does not trap moisture
• Covers 2-4 m² per litre depending on substrate
• Dries in 3-4 hours; fully active after 24 hours
• Resists rain, damp, frost, UV, mould, and algae
• Suitable for brick, stone, render, slate, timber, terracotta
• Solvent-based formula; apply at +5°C to +25°C
• 5-litre container; 18-month shelf life unopened

Bostik Cementone Water Seal for Exterior Masonry and Wood

Single-Coat Protection Against Damp and Frost:

Bostik Cementone Water Seal is a solvent-based exterior water seal formulated to protect porous masonry, brickwork, stone, timber, and terracotta in a single coat. It penetrates the surface to create an invisible, water-repellent barrier that resists rain, damp, and frost damage without altering the appearance of the treated substrate.

Breathable Formula That Lets Surfaces Dry Out:

Unlike film-forming sealers, this water seal remains permeable to water vapour, so moisture already present in the structure can escape rather than becoming trapped. This breathable action helps reduce mould and algae growth, limits dirt retention, and contributes to improved insulation values in treated walls.

Coverage, Drying, and Application:

Coverage is 2 to 4 m² per litre per coat, depending on substrate porosity and application method. The product dries in approximately 3 to 4 hours at temperatures between +5°C and +25°C, with full water-repellent properties developing after 24 hours. Always carry out a test on a small area first, as some surfaces may darken very slightly on application.

Shop our full Painting & Decorating range at Heavins.ie for sealers, primers, and exterior treatments delivered across Ireland.

Key Features

Single coat - one application provides trade-grade water repellency.
Breathable barrier - water vapour escapes, so moisture is not trapped in the structure.
Clear finish - transparent; does not alter the appearance of the treated surface.
Wide substrate compatibility - suitable for brickwork, cement render, cast concrete, roughcast, stonework, limestone, slate, terracotta, wood, and leather.
UV and frost resistant - high resistance to UV light, frost, and general weathering.
Reduces maintenance - limits mould, algae, staining, and efflorescence on treated surfaces.
Fast drying - surface dry in 3 to 4 hours; fully active after 24 hours.
Exterior use only - formulated for above-ground, exposed masonry and timber surfaces.

Specifications

• Brand: Bostik (Cementone sub-brand)
• Product Code: 30812236
• EAN: 5011734010932
• Volume: 5 litres
• Finish: Clear / transparent
• Composition: Polyoxo aluminium stearate based, solvent-borne
• Specific Gravity: Approximately 0.8
• Coverage: 2-4 m² per litre per coat (substrate dependent)
• Number of Coats: 1
• Drying Time: 3-4 hours approximately
• Full Performance: After 24 hours
• Application Temperature: +5°C to +25°C
• Use: Exterior only
• Compatible Substrates: Brickwork, cement render, cast concrete, roughcast, stonework, limestone, slate, terracotta, wood, leather
• Shelf Life: Up to 18 months from date of manufacture (unopened)
• Storage: Cool, dry conditions, +5°C to +25°C, out of direct sunlight; protect from frost

We are pleased to offer FREE delivery on orders over €499.00 to anywhere in the Republic of Ireland and Northern Ireland, and our Click & Collect service is FREE on all orders.

All items are shipped from the Athlone Warehouse in Co. Westmeath, Ireland so no import duties apply to the island of Ireland.

Delivery Costs to Republic of Ireland are €6.99 for orders Under €499.00

Same Day Dispatch €9.99
Orders placed before 12pm are dispatched the same working day, helping your items reach you sooner. Excludes bulky items.

Large Bulky Items
Please be aware that large, bulky items (large appliances, white goods, etc.) have a delivery charge of €39.99 for bulky items or €59.99 for extra bulky items to ROI

- We are now delivering to Northern Ireland with all delivery costs equal to the Republic of Ireland.

View our full Delivery & Collection information

Due to our valued customer feedback, we have updated and improved our Returns Policy.

We now offer an exhange or refund on goods purchased online, and returned 14 days after purchase. 

View our Full Returns Policy