Efflorescence is the formation of salt crystals on or near the surface of concrete. It’s not only terrible to look at but it can get worse over time. It may also be an indication of a more serious problem, like waterproofing issues.
To get efflorescence, two things are required- water soluble salt and water. Water moving through the concrete pushes salt to the surface, then the water evaporates and leaves the white powder behind. The longer you leave it, the worse it gets.
If you get onto it straight away, generally white vinegar will do the trick. If that doesn’t do it, head on down to the hardware store and pick up an efflorescence remover. If the leaching is extensive, it’s highly likely there’s a bigger issue that needs addressed ASAP.
Now, can it be prevented? According to the HIA, most experts will say no. It can, however, be minimised and serious damage avoided. Preventing water from getting in is the number one priority. Physical measures and good design are the most effective means of avoiding efflorescence or leaching. Adequate waterproof membrane, a suitable sealer, good drainage and ensuring a high quality of workmanship are also imperative.