As I always say, no crack is a good crack, and that includes outside foundation cracks. Therefore all cracks should be fixed immediately.

Before answering the question we need to know if it is the foundation that is cracked or is it the coating on the foundation that is cracked. Therefore we do need to address the stucco coat over the foundation known as parging.

What are outside foundation cracks on Parging?

Parging is a stucco coat or finish coat that is applied on a wall made of Concrete Masonry Units (CMUs). Parging is a thin coat of mortar and Portland cement mix applied to a CMU wall to act as a finish coat to improve the appearance and act as a moisture barrier. Parging can be applied to new or existing walls.

Here in New Jersey, we have many homes with foundations made of CMUs that are parged on the outside. It is a very common construction practice. On the exterior of the house we only see the parging, or stucco, coat above grade where it is visible even though typically it does go all the way down the wall to the footing. Herein lies the problem.

Why does parging crack so often?

The same coat of parging on the same wall is both above and below the frost line at the same time. Therefore the parging reacts to freezing and thawing differently on different parts of the wall based upon whether that part of the wall is above the frost line or not.

The parging above the frost line will crack based both upon the parging itself freezing and thawing as well as the adjoin soil freezing and thawing.

The parging is not the foundation.

As we just discussed, the parging coat is applied TO the foundation after the foundation has been constructed. The parging is not the foundation, but rather, a coating on the foundation. Think of the wallpaper on a dining room wall. If the wallpaper tears, it doesn’t mean that your wall is no longer sound. It is the same thing with the parging coat on your foundation. When the parging cracks, it is the parging that has cracked and not the foundation itself.

How to fix cracked parging for under $10

Get an old toothbrush and thoroughly clean the crack. Make sure there is no dirt or debris inside the crack and that the surface is clean.
Go to Home Depot and buy a quart of pre-mixed stucco patch for about $7.28. and a plastic 2” compound knife for $0.98. This ready to use product has a granular texture to blend in with the existing stucco/parging.
Carefully fill the crack with the stucco patch.
If it is the not the parging, but rather foundation that is cracked, you should be very concerned and call a foundation crack repair specialist immediately.