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Silicone vs Acrylic Render Compared
Compare silicone and acrylic external render systems for UK buildings, covering flexibility, self-cleaning, colour range, cost and application methods.
Side-by-Side Comparison
| Feature | Silicone Render | Acrylic Render |
|---|---|---|
| Material cost per m² | £25-40 | £15-30 |
| Installed cost per m² | £50-80 | £35-60 |
| Water resistance | Hydrophobic — beads water | Good — but absorbs more |
| Breathability | Highly vapour-permeable | Lower vapour permeability |
| Self-cleaning | Yes — rain washes dirt | Limited |
| Flexibility | Good | Excellent |
| Colour range | Wide (factory-mixed) | Very wide (factory-mixed) |
| Maintenance-free life | 10-15 years | 5-8 years |
When to Choose Silicone Render
- Exposed sites with heavy rainfall (most of the UK)
- Walls that need to breathe (solid walls, timber frame)
- Premium finish with long maintenance-free life
- Properties where clean appearance is important
- K Rend, Weber or Parex system specifications
When Acrylic Render Is Suitable
- Budget-conscious projects where cost matters more than longevity
- Sheltered walls not exposed to driving rain
- Surfaces prone to movement where maximum flexibility is needed
- EWI systems where the insulation provides the vapour control
- Vibrant or unusual colours not available in silicone ranges
Related Calculators
Use the Rendering Calculator for material quantities, or the Monocouche Render Calculator for through-colour render systems.
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How We Calculate This
Frequently Asked Questions
Silicone render is hydrophobic (water-repellent) and vapour-permeable, allowing moisture to escape from the wall while repelling rain. Acrylic render forms a more impermeable coating that is highly flexible and crack-resistant but less breathable. Silicone render is the premium choice for UK climates due to its self-cleaning properties in rain.
Silicone render is more expensive. Material cost is typically £25-40/m² for silicone (e.g. K Rend Silicone) vs £15-30/m² for acrylic render. Total installed cost including basecoat, mesh and topcoat is approximately £50-80/m² for silicone systems vs £35-60/m² for acrylic. The premium reflects the superior weather performance and longer maintenance-free life.
Yes, silicone render has genuine self-cleaning properties. The hydrophobic surface causes rainwater to bead and run off, carrying dirt particles with it. This keeps the facade cleaner for longer — typically 10-15 years before any noticeable discolouration, compared to 5-8 years for acrylic render. North-facing or sheltered walls may still develop algae over time regardless of render type.
Acrylic render is slightly more flexible and elastic than silicone, giving marginally better crack-bridging ability. However, both modern renders are applied over a reinforcing mesh on a basecoat, which provides the primary crack resistance. In practice, both systems perform well against hairline settlement cracks when properly applied with mesh reinforcement.
Both renders are technically demanding to apply well. Silicone render is especially unforgiving — it must be applied in consistent passes without visible joins. Both require a proper basecoat with embedded mesh, primer coat and then the topcoat. Most manufacturers (K Rend, Weber, Parex) recommend trained applicators and may void warranties for DIY application.
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Last updated: April 2026
Verified against UK standards · estimates only, confirm with your supplier.