Case 4
- Introduction
- Causes of Defects
- Good Practices
- Standards
- Maintenance and Diagnostics
- Remedial
- Similar Cases
- References
Cause of Defects
- Presence of Iron Oxides within the matrix of the stone in the quarry.
- Poor sealing of stone surface.
- Accidental mixing of iron particles in the backing concrete.
It was observed that the rust stains were relatively uniform in relation to the façade and it is more commonly seen in lighter coloured façade. All granites have contents of iron (Ferrode Oxide) within their natural matrix of minerals. The spots of iron will normally spread out upon contact with moisture and sunshine, which creates a relatively less alkaline environment within the stone, encouraging rust growth.
Sometimes, the stain marks are chemicals from the glue/silicon used to secure the brackets to the stone. The coloured chemical which is present in the Glue/Silicon, may be absorbed into the DRY Stone after installation, and penetrated through the whole thickness of the stone and surface on the other side which appears similar to rust staining.