Clay Adhesive & Reinforcement Plaster is a breathable clay adhesive mortar and clay reinforcement plaster for internal wall systems, designed for bonding insulation boards and clay building boards, embedding reinforcement mesh, and creating a strong base for further clay plaster finishes. It is a ready-to-use dry mix made from building clay, blended sands, plant fibres, cellulose and plant starch, making it an ideal choice for natural, vapour-open wall build-ups.
This versatile clay adhesive and reinforcement mortar is especially suited to clay board systems, internal insulation systems and breathable wall build-ups where compatibility and adhesion matter. Applied with a notched trowel or spatula, it helps achieve full contact between the board and the wall, while also providing an excellent base for embedding fibreglass reinforcement mesh. Even in thin applications, it improves surface strength and helps prepare the wall for subsequent clay plaster layers.
Within our system offering, Clay Adhesive & Reinforcement Plaster can also be used as an adhesive and reinforced base coat over Steico Internal insulation board, with mesh reinforcement embedded into the base coat before the final clay finish is applied. This makes it a practical solution for breathable internal insulation build-ups where a natural plaster system is required.
Clay Adhesive & Reinforcement Plaster is applied at a thickness of 1mm to 5mm and offers an approximate coverage of 6.5m² per 25kg bag at 3mm thickness. Each 25kg bag yields around 20 litres of mortar and requires approximately 6 litres of clean water, depending on the substrate and method of application. Drying time is typically around 2 to 4 days, depending on ventilation and background absorbency.
With a vapour diffusion resistance of μ = 5/10, a thermal conductivity of 0.59 W/mK, and an A1 fire classification, this breathable clay adhesive plaster is well suited to natural building, healthy interior environments and vapour-open construction systems.
Key Features
- Breathable clay adhesive and reinforcement plaster for internal use
- Suitable for bonding insulation boards and clay building boards
- Ideal for embedding reinforcement mesh
- Helps form a strong base for further clay plaster finishes
- Application thickness: 1mm to 5mm
- Approx. coverage: 6.5m² per 25kg bag at 3mm
- Approx. water addition: 6 litres per 25kg bag
- Typical drying time: 2 to 4 days
- A1 fire classification
- Suitable for breathable clay wall systems and natural building projects
