Stucco is a term employed to define a specific kind of exterior plaster that is applied as a two- or three-part coating directly onto masonry. Alternatively, it can be applied over wood or metal lath to enhance a log or wood-frame structure.
Stucco deterioration primarily occurs due to water infiltrating the structure of a building. This infiltration can happen through various entry points such as the roof, chimneys, window and door openings, or when excessive groundwater or moisture seeps through or splashes up from the foundation.
Potential causes of deterioration include:
ground settlement lintel and door frame settlement;
inadequate and leaking gutters and downspouts;
moisture migration within walls due to interior condensation and humidity;
vapor drive problems caused by the furnace, bathroom, and kitchen vents; and
rising damp resulting from excessive groundwater and poor drainage around the foundation.
Water infiltration leads to the deterioration of wood lath through rotting, while it causes metal lath and nails to undergo rusting. Eventually, this process weakens the bond of the stucco, causing it to separate from its substrate.
Ensure that you examine the stucco for any signs of cracks, sections that are crumbling, or areas that could potentially allow water to seep in. In the inspection image, the inspector is carefully observing the portion above the window where the stucco meets the window frame. Cracks that appear old and weathered could be a result of the stucco's initial shrinkage or previous settling of the building.
On the other hand, newly formed and distinct cracks might suggest underlying movement behind the walls, which warrants further investigation. Remember that stucco can be cleaned and also painted.