Expansion joints in building walls require specialized treatment to accommodate thermal and structural movements. The primary methods include sealant application, joint filling materials, and mechanical fasteners. Sealants such as polyurethane or silicone are injected into joints to seal gaps and resist moisture. Mechanical fasteners, like steel plates or brackets, reinforce the joint and prevent separation. Regular maintenance, including cleaning and resealing, ensures long-term durability.

Expansion joints are critical for preventing structural damage caused by temperature fluctuations, foundation shifts, and seismic activity. Sealants provide elasticity and weather resistance, with polyurethane sealants maintaining 90% durability over 10 years per ASTM D7234 standards. Mechanical fasteners, such as stainless steel plates, enhance load distribution and prevent joint failure during extreme movements. A 2021 study by the American Society of Civil Engineers (ASCE) found that 60% of building leaks in commercial structures were linked to poorly maintained expansion joints, costing $12 billion annually in repairs. Sealants are 30-50% less expensive than structural solutions like concrete reconstruction, according to the National Ready Mixed Concrete Association (NRMCA). Neglecting joints can lead to 15% failure rates in masonry walls, as reported by the Insurance Institute for Business & Home Safety (IBHS). Proactive treatment reduces maintenance costs by 40% over 20 years, per a 2022 analysis by the National Institute of Building Sciences. These methods balance cost-effectiveness with structural integrity, ensuring compliance with codes like International Building Code (IBC) Section 2107.