Heat may degrade mortar between the bricks, block, and stone. What can this degradation show signs of?

• A. Strength
• B. Weakness
• C. Expansion
• D. Corrosion

Answer: (B)

Heat exposure can cause mortar to dry, crack, and lose moisture, creating stresses as it expands and contracts at a different rate than the bricks, blocks, or stone surrounding it. This weakening of the mortar bond lowers the masonry’s ability to carry loads, so the degradation manifests as signs of weakness in the structure. Look for cracked or crumbling joints, mortar that easily pulls away or sounds hollow when tapped, and areas where the masonry appears loose or leaning. Corrosion isn’t related to mortar degradation, and expansion by itself isn’t the sign of damage—the key indication is the reduced strength and compromised brick-to-mortar bond.