Why does paint blister, peel and flake off after spraying colour steel tiles, and how should this be addressed?

We have encountered clients reporting that within a year of refurbishing colour steel tiles, blistering, peeling, flaking, and rust reappeared. Clients state this has damaged their local construction reputation, forcing them to undertake costly re-refurbishment to restore credibility. The additional labour involved in sanding and cleaning during rework proves significantly more time-consuming, labour-intensive, and expensive, causing considerable distress.

Therefore, we advise users selecting specialised paint for colour steel tile refurbishment not to rely solely on manufacturers' claims. Instead, carefully verify whether the information provided is genuinely reliable.

We assisted the client in analysing the causes of this situation:

Firstly, the selection of paint for the colour steel tiles was unprofessional. Unlike steel structures or beams, which can be coated with any rust-proof paint, colour steel tile roofs have higher requirements for repainting. The paint must withstand high temperatures while also resisting prolonged exposure to rain, snow, and corrosive acids and alkalis. During summer, temperatures on colour steel roofs can reach approximately 70°C, while winter rain and snow may persist for up to a month. The paint must exhibit excellent heat resistance and water immersion performance. Using non-specialised colour steel tile paint can easily lead to water ingress, peeling, and flaking.

Secondly, inadequate surface preparation and grinding. Applying paint directly without thorough rust removal and grinding significantly reduces adhesion between the paint and the panel surface, resulting in blistering.

How should such issues be addressed?

I. Selection of paint for colour steel tile refurbishment.Market offerings for corrosion-resistant refurbishment of colour steel tile roofs vary greatly in quality, with both professional and non-professional products available. What problems arise from non-professional products? Customers who have used them are likely aware that the most severe issue is peeling and flaking within a year, leading to increased costs. We recommend selecting specialised anti-rust emulsions, rust fixatives, or rust converters.

2. After sanding and cleaning the substrate, colour steel tiles must be coated with a rust fixative or rust converter before applying the specialised topcoat.

For colour steel sheet coatings, professional products are advisable. As a 19-year-old manufacturer specialising in the R&D, production, and sales of coating additives, we possess relatively early market application experience and mature technology. Having collaborated with thousands of anti-corrosion enterprises and boasting numerous construction cases spanning over seven years, we offer a comparatively reliable solution. We provide clients with formulation optimisation and design services, delivering one-stop technical support from raw materials to finished products.