Render Systems for Concrete Blockwork

Concrete blockwork behaves differently to brick or fibre cement under render — its high suction pulls moisture out of a base coat faster than most substrates, which is why a single-coat application that works fine on brick can end up patchy, weak, or prone to cracking on block. Unitex addresses this with a build-up designed around blockwork’s suction rate, not a standard render applied and hoped for.

Why Concrete Blockwork Needs a Different Approach

Blockwork’s porosity means the substrate draws water from the render mix unevenly and quickly, which affects both bond strength and the render’s ability to cure properly. The standard response — and the one built into both Unitex systems below — is a two-coat base build-up rather than a single application, giving the render time and material to establish a consistent bond before the texture and protective coats go on. Combined with a texture coat and protective top coat, this brings the full system to four coats, which is the specification builders and renderers should expect and budget for on blockwork projects.

Redi-Render for Concrete Blockwork

Unitex Redi-Render is applied in two coats on blockwork, each up to 5mm thick, building the base coat to the thickness and consistency the substrate needs. It’s the standard specification for blockwork projects without a specific non-combustibility requirement, backed by the same 7-year system warranty as every Unitex render system.

Beach Render for Concrete Blockwork

Where non-combustibility is a compliance requirement — bushfire-prone construction, multi-residential builds, or projects where a building surveyor requires AS 1530.1 certification — Unitex Beach Render offers the same two-coat blockwork build-up in a non-combustible formulation. The first coat is applied up to 10mm, followed by a second coat, before moving to texture and protective coats.

Choosing Between the Two Systems

Both systems are engineered for blockwork’s suction characteristics and share the same two-coat base approach. Redi-Render is the standard specification for most residential and light commercial blockwork projects. Beach Render is the choice where non-combustibility needs to be documented for compliance sign-off. Builders unsure which applies to their project should confirm with the Unitex technical sales team before ordering, particularly on multi-residential or bushfire-affected sites where the wrong system could hold up a building surveyor’s approval.

Getting Blockwork Compliance Right the First Time

Concrete blockwork is common in boundary walls, retaining structures, and increasingly in mainstream residential construction, and getting the render system wrong isn’t just a cosmetic risk — an under-specified single-coat system on high-suction block is one of the more common causes of early render failure and warranty disputes. Specifying the correct two-coat Unitex system from the outset avoids that risk and keeps the project within CodeMark and NCC-aligned compliance expectations.

Full Technical Specifications

Complete application detail for both systems — coverage rates per coat, coating thickness, and drying times — is available on the individual specification pages: Redi-Render Blockwork and Beach Render Concrete Blockwork.

Confirm Your Blockwork System

For concrete blockwork projects anywhere in Australia, the Unitex technical sales team can confirm the right system, review project plans, and provide a full quotation. Call 1800 RENDER, request a quote online, or view the full Base Coat Renders range to compare systems across all substrate types.