In short
In pre-painted steel the paint system determines colour stability, UV resistance and service life. Polyester is economical and common, SMP more durable, and PVDF the top choice for aggressive climates.
Layers of pre-painted steel
- Steel substrate
- Galvanized (zinc) coating
- Pre-treatment (conversion coating)
- Primer (approx. 5 µm)
- Top coat (approx. 15–20 µm)
The back side is usually coated with 5–12 µm of protective backer.
Comparing paint systems
| System | Key feature | Typical use |
|---|---|---|
| Polyester (PE) | Economical, good formability | General roofing and cladding, indoor, appliances |
| SMP | Higher UV and chalking resistance | Sun-exposed facades, long service life |
| PVDF | Superior colour and chemical resistance | Coastal, industrial and architectural projects |
Choosing a colour
The most common RAL colours are 9002 (grey white), 3009 (oxide red), 5010 (gentian blue), 6005 (moss green) and 7016 (anthracite grey). Dark colours heat up more in the sun; thermal expansion should be considered on long spans.
When ordering
Stating substrate thickness, coating class, paint system, RAL code and gloss level together is enough for an accurate quote.
This article was prepared by the İpek Metal technical team. Contact us for values specific to your project.