Deteriorated mortar between the masonry is a sign of what?

• A. Structural instability
• B. Improved insulation
• C. Increased rigidity
• D. No effect

Answer: (A)

Deteriorated mortar weakens the bond between masonry units, so the wall loses its ability to transfer loads and resist movement. Mortar holds bricks or stones in place and helps distribute forces from gravity, wind, and firefighting operations. When that bond deteriorates, sections can crack, bow, or shift, signaling structural instability. This condition does not improve insulation; gaps and leaks from degraded mortar often worsen thermal performance. It also does not increase rigidity—in fact, it makes the wall less stiff and more prone to movement under load. And since there is a real effect on the wall’s behavior, “no effect” isn’t accurate.