Painted brickwork presents a different challenge to bare brick: the render doesn’t bond to the brick itself, it bonds to the paint film sitting on top of it. If that paint is flaking, chalking, or poorly adhered, no render system will hold reliably over the top — which makes assessing paint condition the first real step in specifying a render system for this substrate, not an afterthought.
The Unitex System for Painted Brick
Where the existing paint is sound, intact, and non-flaking, Unitex Polymer Render — available in wet or dry formulation — is applied as the base coat across the full surface. The wet version is mixed with 5–10% Portland cement, or the dry version mixed with water, and applied to the entire wall to build a consistent render base over the painted surface. Once cured, the system is compatible with the full range of Unitex texture and finish coatings, giving the same design flexibility as any other Unitex-rendered substrate.
Why Paint Condition Comes First
Unlike bare masonry, painted brickwork’s suitability for rendering depends entirely on how well the existing paint is holding on. Loose, flaking, or chalking paint won’t provide a stable base regardless of which render product goes over it — the render will only ever be as well-adhered as the paint film beneath it. Builders and renderers should assess and, where necessary, remove or stabilise failing paint before proceeding, rather than relying on the render system to compensate for a compromised substrate.
Common Scenarios
This system is typically specified on renovation projects where an older painted brick home is being updated with a rendered finish, or where a previous coating has reached the end of its serviceable life and a full render is more practical than repainting. It also applies to other low-adhesion painted surfaces where the same paint-condition principle holds, rather than being limited strictly to brick.
Full Technical Specification
Complete application detail — coverage rates, mixing ratios, and drying times — is available on the Painted Walls Render Specifications page.
Confirm Your Substrate Condition First
Because paint condition determines whether this system is appropriate at all, builders and renderers working on a painted brick project should have the surface assessed before ordering — the Unitex technical sales team can advise on suitability based on the paint’s condition and the project’s requirements. Call 1800 RENDER, request a quote online, or view the full Base Coat Renders range to compare against other substrate systems.
