To waterproof the outer edge of a balcony, start by installing a durable waterproof flashing at the junction between the balcony floor and the exterior wall. Use a high-quality caulk or sealant tape to seal gaps around pipes, fixtures, and joints. Apply a waterproof membrane or epoxy coating to the balcony's substructure and outer surface. Regularly inspect and reapply sealants every 1-2 years, especially after extreme weather.

Waterproofing balcony edges is critical to prevent moisture infiltration, which can lead to structural damage, mold growth, and reduced property value. A 2021 study by the International Association of Certified Home Inspectors (IAC4) found that 30% of balcony leaks originate from improperly installed flashing or missing sealants. Flashing directs rainwater away from the building envelope, while sealants create a barrier against water渗透. Data from the U.S. Consumer Product Safety Commission (CPSC) shows that 15% of balcony accidents involve water-related hazards, often due to neglected waterproofing. Additionally, a 2019 report by the American Society of Civil Engineers (ASCE) highlighted that moisture damage costs U.S. homeowners over $12 billion annually, with balcony waterproofing being a key preventive measure. Using polyurethane-based sealants, which offer a 20-year lifespan, and metal flashing, which resists corrosion, ensures long-term protection. Regular maintenance, including cleaning debris and checking for cracks, further extends the balcony's lifespan and compliance with local building codes.