How to Prevent Efflorescence in Masonry

“Efflorescence’ is the term most used to describe the deposit of crusty white mineral salts that appear on a masonry surface (concrete, render, brick or mortar) that have leached out from within the substrate when moisture migrates through it. Efflorescence in masonry appears as white alkaline salts on the surface and consists mainly of calcium carbonate. A reasonable amount of moisture is required for it to form.”

The best way to prevent efflorescence is to consider the following at the design and construction phase:

· Remember, water serves as the vehicle by which soluble salts are transported to the masonry surface, they accumulate as the water evaporates. Take measures to stop moisture migration through any masonry walling.

· Specify non-porous masonry products with low calcium and salt content.

· Ensure mortar joints are full, with no voids (water repellent additives are available).

· Keep all masonry dry during construction by covering with plastic sheeting etc.

· Install appropriate moisture barriers (waterproofing).

· Design details that will prevent the entrance of moisture into the masonry assembly are critical. Details that will direct water collection away from wall tops and horizontal surfaces should be considered. If architecturally feasible, wide overhanging roofs help protect walls from rainfall.

· It is critically important to cover up coloured concrete core filled masonry walls:

(1) during the construction phase and (2) after concrete core filling the wall needs to be covered at the top from moisture ingress whilst the 28 day concrete curing process is occurring. Failing to do this can activate the alkaline salts within the masonry substrate allowing these salts to be transported to the surface.

All Island Block & Paving coloured bricks, blocks and pavers, including the Global Greentag certified “Sustainable Products for the Future” range are manufactured with “Tech Dry” masonry emulsion to provide a durable product for Australian weather conditions that is resistant to moisture.

The emulsion is a liquid admixture that is added to the water content during manufacturing. When blended throughout the coloured products, permeability to water and the occurrence of unsightly efflorescence is virtually eliminated. All Island Block & Paving coloured products are colourfast, water repellent and are designed to repel weathering-related water uptake and efflorescence. Testing is available.