White Stains in Basement Walls: Mold or Efflorescence?

In this video a customer from Courtenay, BC asks Chris about the white, crusty stains in her basement walls.

Chris explains that the white, powdery substance that commonly builds up on concrete walls is not mold, but efflorescence. Efflorescence appears when ground water infiltrates the concrete walls. The water collects salt and minerals from the soil and from the concrete itself, evaporating into the basement, leaving these minerals behind to build up over the concrete surface. Efflorescence is not a health hazard, but it is not something you want to see on your basement walls either. It is a sign of water intrusion and high humidity – all of which can lead to mold growth in the basement. If left untreated, efflorescence can also cause the concrete walls to deteriorate. It is a good idea to get rid of efflorescence as soon as possible to prevent future problems.