Repair Systems — 03 — Facade & External Envelope
Bonding agent & primer systems
Technical product reference for bonding agent and primer systems used before render application on dense, smooth, and low-absorption substrates in Australian facade remediation. Covers acrylic and SBR bonding agents from Mapei, Sika, Fosroc, and Rockcote.
What are bonding agents and primer systems for render?
Bonding agents and render primers are polymer-based liquid admixtures applied to the substrate before render application to improve adhesion on dense, smooth, or low-absorption surfaces where direct render adhesion without a primer may be insufficient.
Product Reference
4 products — 4 brands — bonding agent and primer systems — scroll to view all
Mapei Planicrete AC (Acrylic Bonding Agent)
Acrylic bonding agent / SBR render admixture
System Description
Mapei Planicrete AC is an acrylic-based polymer admixture used as a bonding agent for cementitious renders and mortars. It can be applied to the substrate as a neat slurry brush coat before render application, or added to the render mix water as an admixture to improve polymer content and adhesion. It improves adhesion on dense, smooth, or low-absorption substrates such as smooth concrete and polished masonry where standard render adhesion without bonding agent may be insufficient. Confirm dilution ratio, application method, and compatibility with the render system with Mapei Australia technical. TODO: owner confirm — Mapei Planicrete AC specification, dilution ratios and application guide for render bonding.
Technical Properties
- Acrylic polymer bonding agent and render admixture
- Applied neat to substrate as brush-on slurry coat, or added to render mix water
- Improves adhesion to dense and smooth substrates
Limitations
- Do not allow bonding agent slurry coat to dry before applying render — render must be applied while bonding coat is still tacky
- Confirm compatibility with specific render system — not all bonding agents are compatible with all renders
- TODO: owner confirm — Mapei Planicrete AC specification and dilution ratio
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
SikaBond or SikaLatex (Bonding Agent / SBR Admixture)
SBR bonding agent / latex render admixture
System Description
Sika supplies SBR latex bonding agents and render admixtures for improving adhesion of cementitious renders to dense, smooth, and low-absorption substrates. SikaLatex (or current equivalent) is a styrene-butadiene rubber latex used as a bonding slurry when brushed neat onto the substrate, or as a polymer admixture when added to the render mix water. Confirm the current Sika product for render bonding, dilution ratio, and compatibility with Sika render systems with Sika Australia technical. TODO: owner confirm — current Sika SBR bonding agent product name, dilution ratio and application guide.
Technical Properties
- SBR latex — bonding agent and render admixture
- Applied as neat brush-on slurry or added to render mix water
- Improves adhesion to dense and smooth concrete and masonry
Limitations
- Apply render while bonding coat is still tacky — do not allow to dry
- TODO: owner confirm — current Sika SBR bonding agent product name, specification and availability
- Confirm compatibility with specific render system
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Fosroc Renderoc Primer / Nitobond SBR
SBR bonding slurry and render primer — dense substrates
System Description
Fosroc Nitobond SBR (or current equivalent) is a styrene-butadiene rubber latex used as a bonding agent for cementitious renders and repair mortars on smooth and dense substrates. It is applied as a brush-on bonding slurry to the substrate before Fosroc Renderoc render application to improve adhesion on concrete and masonry substrates where direct render adhesion is insufficient. Confirm current product name, dilution ratio, and compatibility with Fosroc render systems with Fosroc Australia. TODO: owner confirm — Fosroc Nitobond SBR current product name, specification and application guide.
Technical Properties
- SBR bonding agent applied as brush-on slurry to substrate
- Improves render adhesion to smooth and dense concrete and masonry
- Compatible with Fosroc Renderoc render systems — confirm with Fosroc technical
Limitations
- TODO: owner confirm — Fosroc Nitobond SBR current product name and availability
- Apply render while bonding slurry is still tacky
- Confirm compatibility with specific render system
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Rockcote Primer / Acrylic Bonding Agent
Acrylic bonding agent and render primer
System Description
Rockcote / Saint-Gobain Weber supplies acrylic bonding agents and primers compatible with the Rockcote render range. Confirm the specific Rockcote product for render bonding on smooth or low-absorption substrates with Saint-Gobain Weber / Rockcote technical. TODO: owner confirm — Rockcote bonding agent product, dilution ratio and application guide.
Technical Properties
- Acrylic bonding agent and render primer
- Apply to substrate before Rockcote render
- Improves adhesion to smooth and low-absorption substrates
Limitations
- TODO: owner confirm — specific Rockcote bonding agent product and specification
- Apply render while bonding coat is still tacky
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Comparison
Side-by-side comparison of bonding agent and primer systems. Confirm all product selections against the current manufacturer TDS before specifying.
| Product | Brand | Bonding type | Application method | Substrate types | Mix with render | Primary use |
|---|---|---|---|---|---|---|
| Mapei Planicrete AC | Mapei Australia | Acrylic polymer | Brush-on slurry or render mix admixture | Dense concrete, polished masonry | Yes — can be added to mix water | Bonding agent on smooth / low-absorption substrates |
| SikaLatex / SikaBond | Sika Australia | SBR latex | Brush-on slurry or render mix admixture | Dense concrete, masonry | Yes — can be added to mix water | SBR bonding agent on dense concrete and masonry |
| Fosroc Nitobond SBR | Fosroc / Parchem | SBR latex | Brush-on slurry to substrate | Smooth concrete, dense masonry | Confirm with Fosroc | Bonding primer before Fosroc Renderoc render systems |
| Rockcote Primer / Acrylic Bonding Agent | Rockcote / Saint-Gobain Weber | Acrylic | Brush-on to substrate | Smooth concrete, polished masonry, low-absorption | TODO: confirm with Rockcote | Bonding agent for Rockcote render systems |
Do not confuse bonding agents with:
- Render systems — bonding agents are substrate preparation products, not render systems; the render system (two-coat PM, salt-resistant, breathable, etc.) is applied over the bonding agent
- Salt-retardant treatments — these treat the substrate for salt contamination and are a different stage in the remediation sequence; they are applied to the substrate before the bonding agent in salt-attack remediation
- Saline primer — a specialist primer formulated for salt-affected substrates applied before salt-resistant render; different product class from a general bonding agent
- Structural crack repair primers — crack injection and repair primers used in structural crack remediation; different product class from render bonding agents
Disclaimer
This page provides general technical information only. Final product selection must be confirmed against the current manufacturer technical data sheet, project specification, substrate condition, exposure classification, AS 3700, NCC requirements, and applicator warranty conditions. Products marked TODO: owner confirm require verification before specifying. Do not rely on this reference as a substitute for professional engineering or facade consultant advice.