Painting and refinishing sandwich panels: when is a coating repair enough?

First, establish what has been damaged

A scratch on a sandwich panel does not in itself determine the repair method. The depth of the damage, the coating type and the condition of the steel sheet need to be identified. Kingspan distinguishes superficial scratches, where a touch-up may serve a purely aesthetic purpose, from scratches reaching the steel, which require appropriate protection. So not every change in appearance should automatically be painted over.

In your enquiry, it is worth describing what happened: an impact during transport, abrasion after installation or a change developing over time in service. This is a starting point for the assessment, not a diagnosis. A photo showing only a close-up of the scratch may not reveal deformation of the whole panel. That is why we also ask for a view of the entire element and its surroundings.

Touch-up and surface refurbishment are different tasks

Touch-up concerns a limited area of damage. Refurbishment covers a larger area of the existing coating and requires a separate assessment. Balex makes this distinction in its maintenance instructions; where the facing itself is damaged, replacing the element should also be considered. Painting does not replace an assessment of the panel’s condition.

Before ordering the work, let’s define its limits: a single scratch, several spots on one wall, or many panels with a recurring change in appearance. An enquiry for “facade refurbishment” can mean very different works. A scope described in photos and marked on a plan makes it possible to prepare a specific proposal rather than a promise to fix everything with one material.

Why doesn’t the RAL number alone guarantee a matching shade?

The RAL number is useful information for an enquiry, but it is not a promise of an invisible repair. Kingspan warns of possible differences in shade or coating quality after touch-up. The GreenCoat instructions also describe the effect of ageing and the possibility of the surface looking different after repainting, especially with certain substrate textures.

For the assessment, we therefore need information about the coating, the age of the building and the expected result. It is worth agreeing a trial and how the result will be viewed before extending the work. For sign-off, we suggest stating whether the priority is protecting the area, improving the appearance, or both. Phone photos are used for initial screening; they are not a colour standard or a measurement of colour match.

Material, adhesion and warranty need to be checked

The GreenCoat instructions recommend assessing adhesion and system compatibility before refurbishment. We do not automatically apply their detailed recommendations to every panel. The right material depends on the existing coating and the conditions of use. A “for metal” label alone does not settle compatibility.

Kingspan links the surface painting it describes with loss of the warranty on the original coating. That is a reason to check the documents for the specific delivery and any agreements with the manufacturer before intervening. The product warranty and liability for the subsequent repair must be described separately. Changing to a significantly darker colour also requires consultation: the Ruukki catalogue shows that the colour group affects the thermal load taken into account for the panel.

What does Panel Cure+ enquiry screening involve?

Panel Cure+ is a Panel Montage service covering servicing and localised repairs of sandwich panels. We assess an enquiry about coating damage in terms of the specific element and whether the agreed work can be carried out. This article is not an offer to repaint an entire industrial building or a commitment to accept every type of refurbishment.

After the initial review, access to the area, the scope, the method of assessing the result and the necessary technical arrangements must be confirmed. With a broader problem, consultation with the manufacturer or another specialist may be needed. Citing the Kingspan, Ruukki or Balex instructions indicates a source of knowledge; it does not mean that Panel Cure+ is authorised by, or a partner of, these brands.

How do you prepare an enquiry and agree sign-off?

Prepare a set of information that will help distinguish a localised problem from the need for wider renovation:

• site location, wall or roof, and the approximate height of the damage;
• a photo of the whole section of the envelope and a clear close-up with a size reference;
• manufacturer, panel name, coating type and RAL, if you have this data;
• number of areas, approximate sizes and information about previous repairs;
• the expected result and any restrictions on access or building operations.

Do not go onto a roof or platform just to take a photo. Start documenting from safely accessible areas. Before work starts, ask for a written scope and acceptance criteria. Timing, price and whether the service can be carried out need to be confirmed after screening.

Sources and scope of information

Checked on 24 October 2026. Based on the sources listed below. This educational content was prepared by Panel Montage. The procedure depends on the specific panel, coating, damage and manufacturer’s recommendations. This article is not an individual repair assessment or an instruction for working at height.

1. Kingspan: installation guide, chapter 5: inspections and maintenance, edition 08.12.2025
2. Balex Metal: sandwich panel maintenance and washing instructions, 31.01.2024
3. Ruukki / SSAB: maintenance of GreenCoat coated steel, instructions in Polish
4. Ruukki: sandwich panel catalogue, colour groups and temperature effects