Baumit Base Coats for Cement Particle Board

Cement particle boards require a compatible, reinforced base-coat system before a decorative render is applied. This helps create a continuous surface across the boards, strengthens vulnerable joints and reduces the risk of movement or board outlines becoming visible through the finished façade.

The Baumit products in this range include mineral adhesive and base-coat renders alongside alkali-resistant reinforcing mesh. Compatibility with the exact board and proposed finishing system should always be confirmed before installation.

Products in This Range

• Baumit StarContact Grey – A flexible, mineral-based adhesive and base-coat render developed for Baumit external wall insulation systems.
• Baumit StarContact Speed – A fast-setting, flexible mineral adhesive and base coat for Baumit EWI systems. It is also suitable as a base coat over appropriate masonry.
• Baumit StarContact White – A white mineral adhesive and base-coat render offering strong adhesion and vapour permeability.
• Baumit StarTex Fine – A fine, non-slip and alkali-resistant glass-fibre mesh designed for embedding within compatible adhesive and levelling compounds.

Typical Applications

When approved for the selected cement particle board and render system, these products can be used to:

• Create a continuous base across board surfaces
• Reinforce joints between adjoining boards
• Embed mesh across the rendered area
• Reduce the risk of surface cracking
• Prepare the façade for a compatible Baumit finish
• Support external render and EWI installations

Preparing Cement Particle Boards

Boards should be securely fixed, correctly spaced and installed according to their manufacturer’s instructions. The surface must be clean, dry and free from dust, grease and other contamination that could affect adhesion.

Board joints, fixings, corners and openings require particular attention because movement and stress are more likely to occur in these areas. Additional diagonal mesh reinforcement may be required around windows, doors and other openings.

Applying the Reinforced Base Coat

Baumit StarTex Fine should be fully embedded within the wet base coat, with adjoining sections overlapped according to the system specification. The mesh should sit within the base-coat layer and remain completely covered.

Not every cement particle board is automatically suitable for direct rendering. Confirm the compatibility of the board, base coat, primer and finishing render with Baumit or the board manufacturer before work begins. Always follow the relevant technical data sheets for application thicknesses, reinforcement details, drying periods and weather conditions.