VPI Base Coats for High Density Block / Brick / Concrete

High-density blockwork, brick and concrete can have low or inconsistent suction, making suitable preparation important before rendering. This VPI range includes products for regulating suction, improving adhesion, creating a compatible render base and reinforcing the completed system.

Correct product selection will depend on the condition and suction of the substrate, as well as the VPI finishing coat being applied.

Products in This Range

• VPI Accrolor 2 – A suction-control and bonding agent designed to regulate both high- and low-suction substrates. It is suitable for internal and external applications.
• VPI MonoCal Gris GF – A weather-resistant, one-coat render that can be used as either a base coat or finishing coat. It can also provide a suitable base for finishes including VPI MonoCal GM and GF.
• VPI Reinforcing Mesh – An alkali-resistant mesh used with compatible cement, lime and polymer-modified render systems to improve resistance to cracking over masonry backgrounds. rendit.co.uk

Typical Applications

These products may be used for:

• Regulating the suction of dense or variable masonry
• Improving adhesion before applying a compatible render
• Forming a weather-resistant base for selected VPI finishes
• Reinforcing render systems over masonry substrates
• Internal and external rendering projects

Preparing Dense Masonry

The substrate should be sound, stable and free from dust, laitance, release agents, paint, oil and other contamination that could affect adhesion. Loose material should be removed and significant defects repaired before work begins.

Concrete backgrounds must be sufficiently cured, and smooth surfaces may require additional preparation. Always assess the substrate rather than assuming every dense block, brick or concrete surface requires the same treatment.

Where reinforcing mesh is specified, it should be fully embedded within the compatible wet base coat with suitable overlaps. It should not be attached directly to the substrate and covered with only a thin layer of material.

Choosing a VPI Base-Coat System

Consider the substrate’s suction, surface texture, exposure and the intended finishing coat when selecting products. Refer to the relevant VPI technical data sheets for application thicknesses, drying times, coverage and substrate-specific preparation requirements.