Fassa Base Coats for High Density Block / Brick / Concrete

Dense masonry backgrounds such as concrete, engineering brick and high-density block typically absorb less water than lightweight blockwork. Their lower suction and comparatively smooth surfaces can make it more difficult for conventional render or plaster to form a reliable bond without suitable preparation.

This range includes Fassa Bortolo bonding mortars and reinforcement products for preparing compatible dense substrates. Product selection must reflect both the background and the intended finish, as materials designed for cement-based external render systems are not necessarily interchangeable with products used beneath gypsum or lime-gypsum plaster.

Products within this category include:

• Fassa SP22: A cement-based bonding undercoat for suitable brick and concrete backgrounds, suitable for internal and external applications.
• Fassa PAC 272: A synthetic-resin bonding mortar for gypsum and lime-gypsum plaster applied to concrete.
• Fassanet 160: An alkali-resistant glass-fibre mesh used to reinforce compatible base-coat and render systems.

These products can support:

• Improved adhesion to low-suction masonry
• Preparation of smooth concrete backgrounds
• Formation of a keyed surface for later coats
• Localised or full-surface reinforcement
• Treatment of vulnerable substrate junctions
• Compatible internal and external render systems

Before application, remove dust, release agents, surface contamination, weak material and anything else that may reduce adhesion. Smooth or cast concrete should be assessed carefully, as preparation requirements can vary according to its condition and the finishing system.

Always check the individual product data sheet before selecting a bonding treatment. PAC 272 is intended for gypsum-based and lime-gypsum plasters on concrete, whereas SP22 is the relevant cement-based bonding mortar for compatible render applications. Embed Fassanet 160 only within an approved Fassa reinforcement layer and follow the specified overlap and positioning requirements.