Fassa Bortolo Base Coats for External Insulation Board

Fassa Bortolo base-coat products help form a secure, reinforced foundation for compatible external wall insulation systems. The products in this range can be used to bond selected insulation boards, create a reinforced skim coat and prepare the system for a compatible decorative finish.

External insulation boards should always be installed as part of a correctly specified system. Board material, substrate condition, fixings, reinforcement and finishing products must all be compatible.

Products in This Range

• Fassa A96 Base Coat – A grey cement-based adhesive used to bond and skim-coat compatible polystyrene, extruded polystyrene and mineral-wool insulation panels. It can also be used to embed reinforcing mesh within the base-coat layer.
• Fassanet 160 Reinforcing Mesh – A 160g/m² alkali-resistant fibreglass mesh designed to reinforce compatible base coats and improve the system’s resistance to cracking.

Typical Applications

This range can support:

• Bonding compatible external insulation boards
• Skim-coating insulation-board surfaces
• Embedding reinforcement within the base coat
• Strengthening the render system
• Creating an even base for compatible finishes
• External wall insulation installations and refurbishment

Reinforcing the Base Coat

Fassanet 160 mesh should be fully embedded within the wet A96 base coat rather than placed directly against the insulation board. Adjacent sections should overlap according to the system specification, with additional reinforcement used around openings, corners and other areas exposed to increased stress where required.

The mesh should remain within the base-coat layer and must not be visible through the finished surface.

Before Installation

The supporting substrate must be sound, clean, stable and suitable for the proposed external wall insulation system. Remove dust, loose material, coatings and contamination that could reduce adhesion before installing the insulation.

Insulation boards should be securely fitted with staggered joints and an even surface. Mechanical fixings, starter tracks, beads and other components should be selected according to the system design and building requirements.

Always confirm board compatibility and follow the relevant Fassa Bortolo technical data sheets for adhesive coverage, base-coat thickness, mesh overlaps, curing periods and weather limitations.