Have you ever used salt on your sidewalks during those cold winter months to help prevent slips on the ice? Once the weather gets nicer and you no longer need to salt the walkways you may start to notice the sidewalk has a film of white powder on it. That is efflorescence.
Efflorescence is the natural occurrence of salt rising to the surface of a porous material. While it may look scary it is not toxic or harmful but rather cosmetically unpleasant.
Efflorescence is a common occurrence in permeable building materials including but not limited to natural stone, manufactured stone, cement, and brick.
It looks like a white powder or a thin film on the face of the stone., It also tends to also have a chalk or powdery feel to it.
Efflorescence is caused by moisture during or after installation. The moisture causes salt to rise to the surface of stone & mortar which creates the white powder on the stone.
Typically water and a non-wire stiff brush will do the trick. If there are still elements causing efflorescence to the stone veneer it may reappear in the future and be required to be cleaned once more.
Efflorescence can be displeasing to the eye, but in most cases is not harmful to the stone. The best time to clean the efflorescence is when the weather is dry and warm to prevent further moisture.
There is no way to prevent efflorescence from ever happening, but there are a few preventative measures that you can take during and after installation to reduce it from becoming an issue.
● Properly store stone in pallets and off the ground
● Use low-alkali mortars
● Install footings and flashing whenever possible
● Practice Dampproofing
● Keep sprinklers and any landscaping that creates moisture at a distance from the stone
● Clean the stone as needed