PRO-510 Insulated Undercoat is a lightweight insulating undercoat designed for internal walls where you need both improved thermal performance and a reliable background for plaster finishes. Formulated with hydrated lime, Portland cement, mineral fillers and perlite, it creates a breathable and durable base layer that helps improve the thermal efficiency of internal wall surfaces while also helping to level uneven backgrounds. It is particularly well-suited to refurbishment work where internal walls need upgrading before finishing plaster is applied.

Why Choose PRO-510 Insulated Undercoat?

• Helps improve the thermal performance of internal wall surfaces.
• Creates a stable, reliable background for subsequent plaster finishes.
• Suitable for internal application on dense mineral substrates, including blockwork, masonry, stone and concrete.
• Can be applied in multiple layers to help build thickness and level uneven walls.
• Formulated to provide a breathable, durable layer.
• A strong option for refurbishment projects where thermal improvement and surface preparation are both needed.
• Can be applied by hawk and trowel or suitable spray equipment.

Intended Uses

PRO-510 Insulated Undercoat is designed for internal wall applications on dense mineral substrates such as blockwork, masonry, stone and concrete. It is especially useful on refurbishment projects where walls need both surface preparation and a degree of thermal improvement before the application of finishing plasters. Its ability to build thickness in layers also makes it suitable for helping even out uneven internal backgrounds.

Substrate Preparation

Backgrounds should be sound, clean, dry and free from dust, loose material and contaminants before application. Any weak or damaged areas should be removed and repaired beforehand. For high-suction substrates, the data sheet specifies EWI-301 Water-Based Primer, while smoother or lower-absorbency surfaces may require PRO-313 Green Internal Grit to improve adhesion. Proper preparation helps the undercoat bond well and perform as intended.

Product Preparation

PRO-510 should be mixed with approximately 14 litres of clean, cool water per 25kg bag until a consistent, homogeneous mix is achieved. Mechanical mixing should be carried out for around 2 to 3 minutes, while hand mixing takes approximately 4 to 5 minutes. Once the material has started to set, extra water should not be added.

Application

PRO-510 Insulated Undercoat can be applied using a hawk and trowel or suitable spray equipment. It may be built up in layers from 20mm to 120mm, with each individual layer applied at a maximum thickness of 30mm. The material should be applied evenly and levelled with a straightedge to achieve a consistent surface. Additional layers can be applied once the previous coat has set sufficiently, typically the following day.

Application Conditions

Application should be carried out when ambient and substrate temperatures are between 5°C and 25°C. During application and drying, the material should be protected from rapid drying, frost, rain, excessive heat and strong wind so it can cure properly and achieve the expected performance.

Technical Data