Fosroc Renderoc HB40

Product Overview

Renderoc HB40 is a ready-to-use blend of dry powders that requires only the site addition of clean water to produce a highly consistent, medium-weight repair mortar. Based on Portland cements, graded aggregates, lightweight fillers, and chemical additives, it provides good handling characteristics while minimising water demand. The low water requirement ensures fast strength gain and long-term durability. The material is naturally alkaline, protecting embedded steel reinforcement from corrosion. It is suitable for both large-area concrete reinstatement and small localised patch repairs. The cured mortar is highly impermeable to acid gases, chloride ions, oxygen, and water.

Key Features

• Medium-weight high-build formulation — Saves time and cost of multiple applications
• No formwork required — Can be applied in a single pass on vertical and overhead surfaces to appropriate thickness without formwork
• Extremely low permeability — Polymer modification provides effective resistance to water, carbon dioxide, and chlorides
• Excellent bond strength — Strong adhesion to the concrete substrate
• Exceptional shrinkage compensation — Systematic shrinkage compensation mechanism reduces cracking risk
• Single-component pre-bagged — Just add water; pre-packaged formulation eliminates site-batching variations
• No chloride admixtures — Will not accelerate reinforcement corrosion
• Reinforcement protection — Natural alkalinity provides corrosion protection for embedded steel

Applications

• Large-area concrete reinstatement (spalling repairs)
• Small localised patch repairs
• Vertical and overhead concrete repair
• Concrete spalling caused by reinforcement corrosion
• Structural repairs requiring a medium-weight repair mortar

Packaging

25KG bags.

Important Notes

• Not suitable for application when temperature is low and falling
• Do not mix part bags
• Not suitable for areas subject to vehicular or heavy traffic due to its medium-weight formulation
• Heavy rainfall before final set may cause surface scour
• Must be cured after repair in accordance with good concrete practice
• Shelf life is nine months in unopened packs stored in dry conditions
• Wear gloves, eye protection, and dust masks during application
• For detailed application methods, coverage rates, and technical parameters, please refer to the official product data sheet

FAQ

What is the difference between Renderoc HB40 and HB25?

Both are medium-weight repair mortars in the Renderoc range, but HB40 is a higher strength grade suitable for structural repairs with greater strength requirements. HB25 is a lower strength grade that allows thicker single-pass application on vertical surfaces. Select the appropriate grade based on the project's strength requirements.

What priming is needed before applying HB40?

Exposed reinforcing steel should first be coated with Nitoprime Zincrich WB anti-corrosion primer. The concrete substrate should be thoroughly soaked, then a Nitobond SBR cement slurry bond coat should be scrubbed into the surface. Apply the repair mortar as soon as the bond coat becomes tacky.