Efflorescence

Efflorescence is a crystalline deposit of water-soluble salts on the surface of masonry. Although efflorescence is unsightly and a nuisance to remove, it is not harmful to the brick masonry nor does it affect the structural integrity of the masonry. For efflorescence to occur, a number of conditions are necessary; there must be a source of water into the masonry, there must be soluble salts within the masonry, and there must be a path for the water to get to the surface of the masonry and evaporate.

Efflorescence occurs only occasionally and it is difficult to predict when it will occur. However, efflorescence is generally associated with wet and cold weather, and the early life of the building.

The source of the salts may be from either the cement and/ or lime in the mortar, adjacent materials or occasionally the brick.

Building Bloom

In new construction, efflorescence is referred to as "new building bloom", and the source of the water is the moisture within the building material during the construction period. Once the building is completed and the building components dry out to the ambient humidity level, no further efflorescence should be expected.

Minimizing Efflorescence During Construction

Efflorescence can be avoided, or at least minimized, during construction by limiting the amount of moisture which can enter into the brick and/or masonry. Excess moisture in the brickwork increases the risk of efflorescence.

During inclement weather, the brick cubes should be stored on skids, and covered with board. This will prevent the brick from getting saturated before installation.

During construction, the top of all masonry walls and veneer must be covered at work stoppages, especially during inclement weather. The cover should extend a minimum of 2 feet (600mm) down both sides and should be held securely in place. Also avoid storm water run off, from roofs and slabs above, onto the masonry.

This precaution of covering masonry also applies to openings left in masonry during construction. Typical examples include:

• The brickwork below window sills, prior to the installation of the windows and sills
• Tops of parapet walls, prior to the installation of a cap
• The horizontal movement joint below shelf angles, prior to caulking

These openings are generally addressed by another trade, but due to trade scheduling are sometimes left open for a period of time. These openings are ready entry points for water and can result in extensive efflorescence. In these cases, the top of the exposed brickwork should be suitably covered, as described above.