Efflorescence in the form of hair or needle-shaped crystals is often a result of too much moisture in the period just after masonry or pointing work. Water penetrates the porous bricks and dissolves (sulphate) salts. When the wall dries, the salts crystallise on the surface.
This efflorescence often disappears after a few months as it gets rained on. In most cases it can easily be brushed off or removed with a vacuum cleaner. Avoid using water as much as possible, as this will result in even more efflorescence. In severe cases, you can use a high-pressure cleaner when the weather is very dry and the wall has dried out properly. Spray at a 45 degree angle to blow the salts off the wall. Work as quickly as possible, using as little water as possible.
Let the wall dry thoroughly and impregnate the façade completely with WP7-401 Façade Waterproof. This will ensure that no new water can penetrate the wall and the efflorescence will stop quickly.
