Achieving a reliable render finish starts with the correct preparation and the right base material for the substrate. Dense, mineral or challenging backgrounds can require a high-performance render coat that offers strong adhesion, good workability and long-term stability.

EWI-212 High Polymer Render Coat is a polymer-modified, cement-based render designed for use as a durable render coat and levelling layer on a wide range of mineral backgrounds. Suitable for hand or machine application, it provides a reliable solution where strong bonding, flexibility and resistance to cracking are required.

Importantly, EWI-212 is not intended for use as an insulation adhesive or insulation basecoat.

Key Benefits of EWI-212

EWI-212 has been developed to support reliable render application across a range of mineral substrates. Its polymer-modified formulation helps improve adhesion and flexibility, while maintaining vapour permeability and resistance to weather exposure.

Key benefits include:

• Strong adhesion to suitable mineral backgrounds
• Good workability for hand or machine application
• Water and frost resistance
• Vapour permeability
• Improved flexibility
• Enhanced resistance to cracking
• Suitable as a levelling layer from 5–20mm
• Can be reinforced with fibreglass mesh where additional strength is required

Where Is EWI-212 Used?

EWI-212 is suitable for use over a range of mineral substrates, including blockwork, masonry, stone, concrete, aerated concrete, ceramic units, calcium silicate blocks and suitably prepared existing renders.

It is particularly useful where a strong, reliable bonding layer is required on dense or challenging backgrounds. This makes it well suited to render-only applications, renovation projects and areas where the existing substrate needs to be stabilised or levelled before receiving subsequent finishes.

As with any render application, the substrate must always be assessed before work begins. The background should be sound, stable, properly cured and free from anything that could affect adhesion.

How EWI-212 Works

EWI-212 combines cement, hydrated lime, quartz aggregate and performance-enhancing additives to create a durable, polymer-modified render coat.

The polymer modification improves the bond between the render and the prepared substrate, while also increasing flexibility within the render layer. This helps reduce the risk of cracking and supports a more stable background beneath subsequent finishes.

Where additional strength is needed, EWI-212 can also be used with fibreglass mesh. The mesh is embedded into the freshly applied render to improve stability and reinforce the layer, particularly on more demanding backgrounds.

Substrate Preparation

Correct substrate preparation is essential for performance.

Substrates must be sound, stable, properly cured and free from dust, dirt, loose material, grease, release agents and other contaminants that may affect adhesion. Any weak or non-loadbearing sections should be removed before application.

High-suction mineral substrates should be primed with EWI-301 Water-Based Primer. Smooth or low-suction backgrounds can be prepared with EWI-310 Universal Primer where additional key is required. All primers must be allowed to dry fully before render application begins.

Application Overview

EWI-212 should be mixed with approximately 6.5 litres of clean water per 25kg bag. The powder should be added gradually to clean, cool water and mixed mechanically until a smooth, lump-free consistency is achieved. After standing for around five minutes, the material should be remixed thoroughly before use.

The render can be applied by trowel or suitable spray machine at a thickness of 5–20mm. Where reinforcement is required, the fresh render should be combed with a notched trowel before embedding fibreglass mesh into the wet material. Mesh joints should overlap by approximately 100mm, and the surface should be smoothed until the mesh is fully covered.

The surface can then be levelled with a straight edge and finished as required. Final floating should be carried out once the material has begun to take up. Where the following finish requires a key, the surface may be lightly textured while still workable.

Application Conditions

EWI-212 should only be applied when the air, substrate and material temperatures are between +5°C and +25°C.

Rendering should only begin once the substrate has completed its initial settlement, shrinkage and drying period. It should not be applied to damp, unstable or deformable backgrounds.

During application and curing, the render must be protected from frost, rain, excessive heat and rapid drying. In unfavourable weather, protective sheeting should be used on façades, and light misting with clean water may be required to support proper curing.

Technical Performance

EWI-212 is supplied as a grey, cement-based render mortar with a consumption rate of approximately 1.8kg/mm/m², depending on the substrate and application method.

It has a working time of approximately 2–4 hours, although this will vary depending on site conditions. Drying time will also depend on layer thickness, substrate condition and weather exposure.

EWI-212 complies with EN 998-1 and is classified as a CS II render mortar.

Why Choose EWI-212?

EWI-212 is designed for projects where a reliable render coat is required over mineral substrates, particularly where adhesion, flexibility and stability are important.

For installers, it provides a practical solution for challenging backgrounds and render-only applications. Its ability to act as a levelling layer, combined with the option for mesh reinforcement, makes it a strong choice where additional durability and crack resistance are required beneath subsequent finishes.

By selecting the correct primer, preparing the substrate properly and applying the product within the recommended conditions, EWI-212 can help support a more reliable and consistent render build-up.

Conclusion

EWI-212 High Polymer Render Coat is a high-performance, polymer-modified render designed for durable render applications over suitable mineral backgrounds. With strong adhesion, good workability, vapour permeability, weather resistance and improved crack resistance, it provides installers with a dependable solution for challenging render projects.

Used correctly, EWI-212 helps create a stable, reinforced and reliable render layer beneath subsequent finishes, supporting long-term system performance across a range of suitable substrates.

Need EWI-212 for your next render project?
EWI-212 High Polymer Render Coat is available to order from EWI Store, along with compatible primers, fibreglass mesh and render system accessories.