What structure is at risk of crumbling due to heat exposure from a wall?

When considering the risk of crumbling due to heat exposure, veneered masonry emerges as the correct answer. Veneered masonry typically consists of thin layers of brick or stone attached to a structural wall. When exposed to high temperatures, the materials can respond differently; for instance, the outer veneer may experience significant thermal expansion and eventual loss of adhesion to the underlying structure.

This can lead to the face of the wall cracking or even detaching from the supporting material behind it. In contrast, concrete blocks and brick walls have more robust structural integrity and are less prone to failing in such a manner due to their solid composition. Steel beams can also lose structural integrity when subjected to extreme heat, but they do not "crumble" in the same sense as veneered masonry, instead they may warp or lose their load-bearing capacity. Thus, the unique construction of veneered masonry makes it particularly vulnerable to crumbling under high heat exposure.