What is new building bloom and how can it be prevented?
New building bloom is efflorescence that appears on the building shortly after construction, as moisture within the walls dissipates. Masonry walls contain considerable moisture from mixing water not used in the hydration process. Portland cement contains free alkali solutions of sodium and potassium hydroxide. These compounds can migrate to the surface and cause new building bloom. The occurrence of new building bloom can be reduced somewhat by using lower-alkali cement in mortars. Often confused with new building bloom, efflorescence caused by excessive water penetration occurs when water penetrates masonry walls and leaches salts from the brick or lime from the mortar. It normally will appear below the area where water is penetrating the wall. Unlike new building bloom, this efflorescence will continue until the source of water penetration is corrected. Widespread efflorescence may indicate a problem with the brick. If efflorescence continues or recurs, investigate to determine the cause of the problem.