What would be an example of internal deterioration that would NOT be classified as external obsolescence?

Internal deterioration refers to the physical decline of a property that originates from factors within the building itself rather than external influences. Crumbling walls and ceilings represent a significant indication of such internal deterioration, as this type of damage often results from issues like water damage, poor maintenance, or structural problems. This deterioration impacts the condition and functionality of the property directly.

In contrast, external obsolescence is caused by factors outside of the property that can negatively influence its value, such as nearby commercial development or the noise created by a construction site. Both of these examples indicate external factors that can detract from the desirability of a property without affecting its physical structure directly.

Thus, the correct answer highlights that crumbling walls and ceilings are a clear instance of internal deterioration, while the other options illustrate conditions stemming from outside the property that contribute to external obsolescence. Understanding the distinction between internal and external issues is essential for valuing property effectively and recognizing how various factors impact real estate value.