Aged buildings (15–25+ years)
Natural ageing of the plaster creates microcracks. A standard acrylic can't follow them - cracking prematurely as a result.
When Is an Elastomeric System Needed?
Not a "luxury upgrade" - a technical choice where it's truly needed
What an elastomeric coating actually is
Elastomeric paints have high resin content, increased film thickness, and enhanced elasticity. Unlike a standard acrylic, they can follow minor substrate movements.
Their key property: crack-bridging ability. They can bridge microcracks up to 2 mm without the film splitting - precisely where a standard acrylic would crack.
Four scenarios where it's essential
Not every building needs an elastomeric system. But in four specific scenarios, a standard acrylic simply isn't enough.
Hairline cracks
If the cracks are superficial (spider-web pattern), an elastomeric can bridge them without any structural intervention.
Intense sun exposure
Day–night temperature swings on south- and west-facing facades create expansion–contraction cycles beyond what acrylics can handle.
History of failures
If the building has been repainted with acrylic and cracks reappeared, repeating the same approach won't yield a different result.
Three scenarios where it's not enough
Elastomeric coatings bridge - they don't repair. In three specific cases, the root cause must be addressed first.
Structural cracks
Diagonal, deep, at window corners. These can't be bridged - they need structural repair before anything is painted.
Deteriorated plaster
Crumbling, delaminated, or powdery plaster. No paint - elastomeric or otherwise - will hold on an unstable substrate.
Active moisture
If moisture is present, an elastomeric coating may trap vapour - making things worse instead of better.
Acrylic vs elastomeric: the comparison
| Property | Acrylic | Elastomeric |
|---|---|---|
| Elasticity | Limited | High (300%+) |
| Crack bridging | None | Up to 2 mm |
| Film thickness | 80–120 μm | 200–400 μm |
| Initial cost | Lower | Higher (20–40%) |
| Ideal for | New buildings, good plaster | Aged buildings, microcracks |
Elastomeric costs more upfront - but on buildings with cracks, the savings from avoiding re-painting justify the difference.
How long does an elastomeric system last
With proper preparation, an elastomeric system lasts 8–12 years in an urban environment, and even longer in milder climates.
Real-world lifespan depends on three factors: substrate quality, proper priming, and correct film thickness. If any of these is missing, the service life drops dramatically.
Making the right decision
The elastomeric decision shouldn't be driven by marketing or "what the neighbours did". It's a technical choice made after on-site assessment.
Three key questions: Are there cracks? If yes, structural or hairline? Is moisture present? The answers determine whether the solution is elastomeric, structural repair, or moisture treatment first.
It's not a "luxury upgrade". It's a technical solution applied only where it's truly needed.
Related Articles
Why Do Cracks Appear After Painting? DFT: Dry Film Thickness Paint Failure Analysis (Root-Cause) Acrylic vs Silicone-Based Paints
Paints for Building Facades
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