Table of Contents
A facade is only as good as what’s underneath it. You can specify the most beautiful texture finish on the market, but if the base coat isn’t right for the substrate and conditions, problems will show up sooner or later – cracking, delamination, or surface defects that undermine the whole job.
That’s why base coat selection matters. And it’s why Unitex has developed a range of base coat renders engineered for different substrates, applications, and performance requirements.
Here’s how to choose the right one.
What Does a Base Coat Render Actually Do?
Before we get into product specifics, it’s worth understanding the role a base coat plays in the render system:
Adhesion – The base coat bonds to the substrate, creating a stable foundation for everything that follows. Poor adhesion here means the whole system can fail.
Levelling – Base coats fill minor surface irregularities, creating a more uniform surface for the finishing coat. This is especially important on substrates like blockwork or rough brickwork.
Crack resistance – A good base coat absorbs minor substrate movement without cracking. This is where acrylic polymer technology makes a real difference over traditional cement renders.
Protection – The base coat contributes to the wall’s overall weather resistance, working with the finish coat to keep moisture out while allowing vapour to escape.
In short, the base coat is doing a lot of heavy lifting – even though it’s the layer nobody sees.
The Unitex Base Coat Range
Unitex offers several base coat renders, each formulated for specific applications. Here’s an overview of the key products in the Unitex base coat range:
Redi-Render™ (Non-Combustible)
A trowel-applied, polymer-modified base render certified non-combustible to AS 1530.1. It’s suitable for one-coat or two-coat application on masonry substrates like brick and block, both interior and exterior. Its non-combustible rating makes it a smart choice for projects where fire compliance is a consideration.
Fast-R Render (Non-Combustible)
Engineered for speed. Fast-R is a rapid-setting base coat that lets you move to the next stage faster – ideal when project timelines are tight. Also certified non-combustible to AS 1530.1, so you’re not sacrificing compliance for speed.
Beach Render (Non-Combustible)
Designed to deliver a natural, sandy coastal aesthetic while maintaining non-combustible certification. It’s a good option when the base coat will be left exposed or lightly finished.
Polymer Render (Wet and Dry)
Versatile acrylic polymer renders available in wet (ready-mixed) and dry (bag) formats. These are workhorses for general rendering applications, offering excellent adhesion and flexibility across a range of substrates.
HiLite Render™
A lightweight, high-build base coat designed for applications where a thicker render build-up is needed without adding excessive weight. Useful for levelling uneven substrates or achieving specific architectural profiles.
Base Board Render (BBR 8.5)
Purpose-formulated for application over Unitex Base Board cladding panels. This ensures compatibility between the render and the EPS substrate, maintaining system integrity and warranty coverage.
Non-Combustible Renders: Why It Matters
You’ll notice several Unitex base coats carry AS 1530.1 non-combustible certification. This isn’t just a technical footnote – it’s increasingly important for compliance.
Following reforms to the National Construction Code and heightened scrutiny on facade materials (particularly after high-profile cladding incidents), specifiers and certifiers are paying closer attention to the fire performance of external wall systems.
A non-combustible base coat gives you:
- Confidence in NCC compliance for relevant building classes
- Reduced risk during certification and inspection
- Peace of mind for building owners and occupants
Unitex’s non-combustible range – including Redi-Render, Fast-R, Beach Render, and Harbour Fine – provides options without compromising on workability or finish quality.
Matching Base Coat to Substrate
Different substrates have different needs. Here’s a quick guide to matching Unitex base coats to common substrates:
| Substrate | Recommended Base Coat(s) | Notes |
| Clean brickwork | Redi-Render, Fast-R, Beach Render | One or two coat application depending on condition |
| Concrete blockwork | Redi-Render, Fast-R | High-suction substrate – may need primer |
| Painted surfaces | Polymer Render (with prep) | Cross-hatch adhesion test required first |
| Fibre cement sheet | Polymer Render, HiLite Render | Flexible substrates need flexible renders |
| AAC panels (Hebel) | Polymer Render, Redi-Render | Check manufacturer compatibility |
| Unitex Base Board | Base Board Render BBR 8.5 | System-specific – maintains warranty |
| Concrete | Polymer Render, Redi-Render | Dense surface – primer recommended |
When in doubt, check the Unitex System Specifications or contact the Unitex technical team for advice.
Application Tips for Better Results
Even the best base coat won’t perform if application is poor. Keep these principles in mind:
Surface preparation is everything – Clean, sound, and properly primed substrates make all the difference. Don’t skip this step.
Respect the thickness limits – Each product has a maximum recommended thickness per coat. Exceeding it leads to curing problems and cracking.
Allow proper curing – Don’t rush to apply the finish coat. Base coats need to reach the specified moisture content (typically below 12% WME) before overcoating.
Control your environment – Avoid application in extreme heat, direct sun, or when rain is expected. Weather affects curing and final quality.
Use the right tools – Trowel, spray, or float – check the product data sheet for recommended application methods.
Explore the Full Range
The right base coat sets up everything that follows. With Unitex, you’re choosing products that are Australian made, substrate-matched, and backed by over 40 years of industry experience.
View Unitex Base Coat Renders to explore the full range, download data sheets, and find the right product for your project.
Contact Unitex for technical advice or to request a quote.
You May Also Like
