Why Coatings Fail — and How to Prevent It
The Paint Is Usually Innocent
When a freshly coated surface fails within a year — peeling at the edges, blistering, rusting through, flaking in the rain — the instinct is to blame the product. It is almost always the wrong target. A modern coating from a reputable system, applied correctly to a properly prepared surface, does not let go in twelve months. When it does, the failure was built in before the first coat was opened.
Coralex Painters has specified and remediated coatings across Ghana since 1984, and the failures we are called to fix share a small number of root causes. Understanding them is the difference between buying a finish once and buying it again every other year.
The Real Causes of Early Failure
Skipped or Inadequate Preparation
This is the leading cause, by a wide margin. A coating bonds to what is beneath it. If chalk, dust, grease, failed previous coatings, or laitance is left in place, the new coat bonds to that — not to the substrate — and lets go with it. Preparation is not the boring part of the job; it is the job.
Wrong System for the Surface
An interior emulsion on an exterior frontage chalks and fades. A wall paint on exposed steel rusts straight through it. The system has to match the surface and its exposure — exterior steel near the coast needs a corrosion system specified to the right ISO 12944 category, not a decorative coat that was never engineered to protect metal.
Coating Over Active Damp
Painting over a wet wall traps moisture behind the new coat, which then blisters and peels as the water tries to escape. The moisture source must be found and stopped first — no coating survives over active damp, however good it is.
Insufficient Film Build
A system needs a minimum thickness to perform. Two thin coats where three were specified, or a single pass where two were needed, leaves the coating below the build it relies on. This is invisible at handover and obvious a season later — which is why it is worth verifying.
How to Prevent It — Verify, Don’t Assume
Failure is preventable, and prevention is measurable:
- Surface preparation to the right standard before any coat — the single biggest lever.
- System matched to surface and exposure — ISO 12944 category for exterior steel; the right binder for masonry, trim, and floors.
- Dry-film thickness checked to ISO 2808 — confirms the coating was built to the thickness it needs.
- Adhesion confirmed to ASTM D3359 where bond is critical — confirms it is actually holding.
- Documented handover — colour, batch, and product records, so the next maintenance cycle matches.
A coating that is prepared, specified, and verified does not fail early. One that is rushed on an unprepared surface fails on schedule.
Get It Right the First Time
For a free on-site survey that specifies the right system and verifies the work — across Greater Accra, Tema, Takoradi, Kumasi, and Lomé, Togo — call Coralex Painters on +233 23 063 0014.
See our Industrial Coatings, Waterproofing & Protective Coatings, and Commercial Painting services.