Most people have seen “efflorescence” even if they didn’t know what it was or that it even had a name.

Some people have even mistaken it for mold.

The typical “whitish build-up” visible on masonry structures is caused by moisture moving through the material.  As the moisture evaporates from the surface, the salts carried in the moisture builds up to create what we call “efflorescence.” Depending on the types of salts picked up, the efflorescence can sometimes be yellow or pink or even blue.  One should be suspicious of an oil spill, possibly a leaking oil tank, with yellow efflorescence.

It is very common on foundations below grade that have not been adequately sealed on the exterior or that are for some other reason being impacted by sub-surface water.  Moisture can also wick up through the foundation footing and then evaporate out through the wall.  While mostly cosmetic (in some cases it can lead to spalling and weakening of the concrete or brick structures), the main thing that is indicated by efflorescence is:  “there is moisture in the material.”  The first picture shows typical efflorescence on a basement wall.

This next picture shows where efflorescence “grew in areas that were not covered by the plastic ground cover (the plastic ground cover has been removed for picture taking purposes).

This next picture shows a “close-up” of the delicate structures that are sometimes created.

This picture is of severe efflorescence on the face of a fireplace.

Efflorescence is also very common on the faces of brick chimneys at the exterior of the home, or in attics and crawl spaces–or even hidden behind finished surfaces that cover masonry structures.  Here is a picture of efflorescence on the base of a chimney in a crawl space.

This is usually the result of failing chimney mortar caps, missing flue hats, failing mortar joints and/or cracks that can also allow moisture into the chimney structure.  The moisture can then travel through the chimney structure and come out in other parts of the chimney–creating the efflorescence.  The chimney in this next picture almost looks like it had been painted white and now most of the paint is gone.

Efflorescence can easily be cleaned from masonry surfaces—-but it will be back—-if the moisture conditions are not addressed.

By Charles Buell, Real Estate Inspections in Seattle

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