Adhesion is not the only question
A coating can appear firmly attached at the surface while underlying areas are hollow, cracked or unstable. Covering defective material can hide the problem rather than solve it.
What needs checking
- Whether the existing finish is bonded across the elevation
- Cracks, movement and water ingress
- Paint or coatings that could affect adhesion
- Depth around windows, doors and roof details
- The system manufacturer’s requirements
Photographs are a useful first screen, but tapping, inspection and sometimes local opening-up may be required before a firm specification is offered.