Autoclaved aerated concrete strips or panels were attached to the building’s blockwork walls to serve as the decorative mouldings. Spalling of a decorative moulding was reported and extensive cracking was observed across the decorative moulding.
The reason for spalling was found to be insufficient waterproof detailing at the interface between the decorative moulding constructed from autoclaved aerated concrete and actual building block wall.
Water bypassing the gap between the decorative moulding and block wall or the crack on the moulding resulted in corrosion of the attachment pin and hence spalling.
Spalling of decorative moulding from the façade
Water able to bypass insufficiently waterproofed interface between autoclaved aerated concrete and actual building wall
The spalled decorative moulding was reconstructed with patch repair mortar.
As a preventative measure, all interfaces between the decorative mouldings and building walls were sealed, waterproofed and repainted.
The interfaces of decorative moulding and building walls were sealed, waterproofed and repainted
