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ROOFBOND EP
- Joining new concrete to old
- Structural concrete extensions
- Column and wall repairs
- Bonding on damp surfaces
ROOFBOND EP is a two-component, solvent-free epoxy resin bonding agent for producing excellent bond strength between old and new concrete and cementitious surfaces. Brush-applied in a thin film, it cures to a high-strength epoxy bond layer with an open overlay window of 2–3 hours at 30°C and 5–6 hours at 20°C. It delivers 52 N/mm² compressive, 36 N/mm² flexural and 25 N/mm² tensile strength. Suitable for both damp and dry surfaces. Approved and extensively used across CPWD, PWDs, APGENCO and government infrastructure projects.
Specifications
Figures are controlled laboratory results. Actual site performance varies with substrate, temperature, humidity, application method and workmanship — please confirm the current product datasheet before specification.
Where to use ROOFBOND EP: epoxy bonding agent for old and new concrete
ROOFBOND EP is an epoxy bonding agent in two components, solvent-free, for bonding new concrete to old concrete and cementitious surfaces. You mix base and hardener, then brush it on as a thin, continuous film that cures to a high-strength bond layer. It works on damp and dry surfaces alike.
New-to-Old Concrete Bonding
Brush on a thin film, then pour while it is still tacky.
Structural Concrete Extensions
Bonds extensions to loaded structures such as factories and buildings.
Dam Piers & Spillways
Used for critical repairs and extensions on dam piers.
Bridges & Highways
Bonds new concrete to existing bridge and road structures.
Column & Wall Repairs
Suits vertical as well as horizontal structural elements.
Formwork & Reinforcement Applications
Open time allows steel and formwork to be fitted before the pour.
Damp & Dry Surface Bonding
Bonds to damp or dry surfaces, but do not let water collect.
At a concrete extension cold joint, timing decides the bond. Mix base and hardener 65:35 for 3 minutes and use within the pot life of 1.5–2 hours. The overlay window is 2–3 hours at 30°C or 5–6 hours at 20°C. Strengths to BS 6319 are 52 N/mm² compressive, 36 N/mm² flexural and 25 N/mm² tensile, and coverage is 2–2.5 sq.m per kg. This CPWD approved bonding agent must still be tacky when the new concrete or ROOFCRETE EP is placed.
Armstrong Chemicals supplies ROOFBOND EP to sites across Telangana, Andhra Pradesh, Karnataka, Kerala and Tamil Nadu, including Hyderabad, Vijayawada, Bengaluru, Kochi and Chennai.
Temperature-Controlled Placement. A Lifetime of Bond.
A solvent-free epoxy bonding agent with an open overlay window of 2–3 hours at 30°C and 5–6 hours at 20°C — while delivering 36 N/mm² flexural strength and 25 N/mm² tensile strength in the bond layer between old and new concrete.
Get a QuoteWhy New Concrete Fails to Bond to Old
Without a bonding agent, new concrete placed against existing concrete or cementitious surfaces relies only on mechanical interlock — which deteriorates under load, vibration and thermal cycling, causing delamination at exactly the repair interface.
The ROOFBOND EP Advantage
A solvent-free epoxy bond coat that chemically integrates with both old and new concrete — delivering 52 N/mm² compressive, 36 N/mm² flexural and 25 N/mm² tensile strength at the interface.
Temperature-Controlled Overlay Window
The open overlay window is 2–3 hours at 30°C and 5–6 hours at 20°C. Place new concrete while ROOFBOND EP remains tacky.
Damp Surface Compatible — No Drying Wait
ROOFBOND EP can be applied to both dry and damp surfaces — eliminating the drying time that delays conventional concrete bonding agents and making it practical for in-situ structural repairs where surface moisture cannot be fully controlled.
Specified by Central & State Government Bodies
Two Phases — Prepare, then Mix, Apply & Place
A straightforward two-phase system with a 1.5–2 hour pot life and a temperature-dependent window to place the new concrete.
- •Sound substrate — clean, free from dirt, dust, grease and oil
- •Wire brush, water wash and detergent scrub; scabble or grit-blast to remove laitance
- •Do not allow water to pool on the surface before application
- •Mix Part 1 (Base) : Part 2 (Hardener) = 65:35 for 3 minutes with low-speed stirrer until uniform colour
- •Above 35°C: shade components before mixing. Below 5°C: warm components in hot water
- •Apply by brush in a thin, continuous, even film — pot life 1.5–2 hours
- •Place new concrete or ROOFCRETE EP within 2–3 hours at 30°C or 5–6 hours at 20°C while ROOFBOND EP is still tacky
- •Clean all tools immediately with thinner — not water, not acetone
Built for Structural Bond
A solvent-free epoxy bond coat that gives site teams time — and gives structures a bond that lasts.
Bond Strength That Exceeds Concrete
Flexural strength of 36 N/mm² and tensile strength of 25 N/mm² — bond strength at the interface that exceeds the tensile capacity of the concrete itself.
Temperature-Controlled Overlay Window
Place new concrete within 2–3 hours at 30°C or 5–6 hours at 20°C, while the epoxy bond coat remains tacky.
Damp & Dry Surface Compatibility
Applied to both damp and dry concrete surfaces — no waiting for surfaces to dry before applying the bond coat, making it practical for in-situ structural repairs.
High Chemical Resistance
Highly impermeable to most chemicals with compressive strength of 52 N/mm² for structural bonding applications.
Packing, Coverage & Shelf Life
Available in 1 kg, 1.5 kg and 15 kg packs. Coverage: 2–2.5 sq.m per kg applied by brush. Shelf life of 1 year from manufacture, in cool and dry storage in original unopened containers.
Flammability & Safety
⚠️ Flammable — no flames or fire during application. Wear hand gloves during application. Skin contact: wash immediately with soap and water. Eye contact: wash immediately with plenty of water and seek medical advice.
Pot Life vs Overcoat Window
Mixed ROOFBOND EP must be applied within 1.5–2 hours (pot life). After application, new concrete or ROOFCRETE EP must be placed within 2–3 hours at 30°C or 5–6 hours at 20°C, while the bond coat is still tacky. Clean all tools with thinner immediately after use.
How to Use
Ensure the surface is firm, clean and free from dirt, dust, grease and oil
Clean using wire brushing, water washing and appropriate cleaning agents — do not allow water to collect on the surface
Remove roughness and laitance by scabbling the affected area until a sound substrate is achieved; use detergent scrubbing or steam cleaning for oil and grease
Pour the entire contents of Part 1 (Base) into a clean empty container
Pour Part 2 (Hardener) into the same container — ratio 65:35 (Part 1 : Part 2)
Mix thoroughly for 3 minutes using a low-speed mechanical stirrer until a uniform colour is achieved
⚠️ Pot life is 1.5–2 hours — apply within this window
Temperature above 35°C: keep components in shade before mixing. Below 5°C: warm components in hot water before mixing
Apply the mixed ROOFBOND EP by brush in a thin, continuous, even film over the prepared surface
⚠️ Place new concrete or ROOFCRETE EP within 2–3 hours at 30°C or 5–6 hours at 20°C — while ROOFBOND EP is still in a tacky condition
Clean tools immediately with thinner after use
Applicable Areas
Coverage Calculator
Coverage estimation is not applicable for this product. Please contact our team for application guidance.
Product Brochure
Download Technical Datasheet
Full specifications, application systems, layering guides, and coverage tables.
Frequently Asked Questions
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