Case 1

Cause of Defects

Water penetration into brick walls is always a potential source of damage. It results in visible wetting of walls, ceilings and floors, blistering paint, bulging plaster, mould on surfaces and fabrics, leaching the cementitious materials and so on. It can also reduce the effectiveness of thermal insulation.

1. Moisture from condensation: Condensation problems can occur in air-con buildings when warm, moist outdoor air is driven towards cooler, drier interior spaces.
2. Rain penetration through cracks in the solid wall either at mortar joints or unprotected joints around window, doors and other components.
3. Rising dampness due to: lacking damp proof course or damp proof membrane bridged by pointing and rendering.
4. Dampness from construction moisture: The fabric of new building or building components contains water used in the concrete, mortar and plaster. This moisture can take a long time to dry out. If protection is inadequate, rainwater can also saturate the building or building components while new building is under construction, or old building under repair.
5. Water penetration may also be due to poor bonding between the mortar and the bricks.

As bricks and mortar are not themselves waterproof, there is always some risk of rain penetration through brickwork, especially if it is poorly constructed or experiencing a higher degree of exposure to driving rain. Moisture may also penetrate through the hairline cracks in the fabric or any capillary paths between the bricks and the joints.

Consequences

Other problems such as efflorescence and corrosion of brickwork may occur.

• Migration of water into the internal areas.
• If left unrepaired and more water seeps into the internal face, the whole paint film will peel off. Damage could be done to the interior finishing.