Question:

I have a problem with some unsightly brickwork on the front of my house. It is on a front porch area with soil behind the brick. In the past, someone applied a white sealer to the mortar. In a year’s time, the white sealer seems to come out of the mortar and dissolve on the bricks. It appears as though some fungus might loosen the painted mortar. Could this be moisture forcing its way through the mortar? The mortar seems to be deteriorating.

Answer:

I am pretty sure the condition you are experiencing is called “efflorescence.” Efflorescence appears as white stains on masonry and is the result of water getting in and pulling out the water-soluble salts, leaving a white powdery deposit on the surface of the masonry as the water evaporates.

Typically, the best removal method would be with a dry brush. Rinsing with water or hand washing with a mild detergent and a stiff-bristle brush may also be effective. Some people just let the natural weathering process do the work.

Cleaning the efflorescence does not cure the problem. After cleaning, you may experience the efflorescence again. Once the area is cleaned, it should be sealed, to prevent new moisture from entering the masonry. Since moisture must be present for efflorescence to appear, any other steps you can take to keep water away from the wall will be helpful (gutter cleaning, proper drainage, etc.)

I would recommend that you contact a mason to confirm the presence of efflorescence and to look at the deteriorating mortar to see if repair is in order.