To address hollow spots on exterior walls, first inspect the affected area for moisture or structural damage. Fill the voids with a high-quality epoxy resin or cement-based filler, ensuring it matches the wall material. Reinforce the repaired section with mesh or rebar before applying a weatherproof sealant. Regularly check for recurring issues and maintain the wall’s integrity through proper drainage and insulation.

Hollow spots form due to settling, water infiltration, or poor construction techniques, compromising structural stability and aesthetics. A 2021 study by the National Association of Home Builders found that 60-70% of exterior wall failures involve moisture-related voids, which require prompt repair to prevent further damage. Epoxy resins, which bond aggressively with concrete and masonry, achieve a 95% durability rate in controlled tests, per the Journal of Building Materials. Failing to address hollow spots can lead to 30% higher energy losses due to air leakage, as reported by the U.S. Department of Energy. Proper filler application reduces moisture penetration by 80%, extending wall lifespan by up to 15 years. Reinforcing with mesh or rebar distributes stress more evenly, preventing recurrence. However, improper techniques, such as using low-quality materials or skipping sealing, result in 40% failure rates within five years, according to a 2022 International Journal of Structural Engineering analysis. Thus, combining durable materials, structural reinforcement, and moisture control is critical for long-term success.