The most frustrating structural issues during old house renovation are undoubtedly water leaks and wall efflorescence. These two problems not only ruin living quality but also lead to much higher long-term maintenance costs if not fully addressed. Mastering their causes, correct detection methods and permanent fixes is critical to a successful old house renovation project.
Causes of Leaks and Wall Efflorescence
Old buildings bear clear signs of aging, and leaks and wall efflorescence rarely stem from a single cause—they are usually the result of multiple cumulative factors.
Structural Cracks and Material Aging
After decades of weathering and fluctuating temperatures and humidity, concrete, brick walls or cement mortar in old houses often develop tiny micro-cracks that are invisible to the naked eye. These cracks act as pathways for moisture to seep in. Waterproof layers on roofs, exterior wall paints, window sealants and other materials harden, become brittle or peel off over time, losing their original waterproof function and allowing rainwater or moisture to infiltrate.
Old Plumbing Issues
Old water supply and drainage pipes, especially cast iron pipes, may have corroded through or loosened joints. Minor leaks from pipes inside walls or under floors are hard to detect, but over time they will cause wall dampness, breed wall efflorescence and even affect downstairs neighbors.
Environmental and Design Factors
Taiwan’s humid climate provides ideal conditions for wall efflorescence. Poor ventilation in old houses and large indoor-outdoor temperature differences can cause water droplets to condense on walls. Additionally, common design flaws include too short eaves, clogged gutters, improper waterproofing for extended balconies, and window positions that directly expose walls to rainwater.
Effective Ways to Detect the Source of Problems
Random patching and repairs often lead to wasted time and materials. Following proper detection steps can accurately pinpoint the source of issues and avoid unnecessary costs.
Visual Inspection and Environmental Observation
First, conduct a comprehensive visual check. Look for water stains, cracks, peeling paint or white, green or black mold spots on walls and ceilings. Pay special attention to areas around window frames, near pipe joints and ceiling seams. Inspect roofs, balconies and exterior walls for damage or standing water. Record all suspicious areas and note changes after rainy seasons.
Instrument-Assisted Testing
For issues that are hard to identify with the naked eye, professional tools can help. Infrared thermal imaging cameras can show temperature differences on walls to locate hidden moisture areas; moisture meters can quantify the humidity of walls or floors to determine if dampness is on the surface or from internal leaks. If you suspect pipe problems, hire a plumber to perform a pipe pressure test or endoscope inspection.
Zone Testing Method
If you cannot locate the source of water, use the zone testing method. For example, temporarily turn off a section of water pipes to see if wall dampness improves, or perform a water spray test (simulating rain) in specific areas to check if rainwater seeps in from certain spots. Operate carefully to avoid causing secondary damage.
Permanent Fixes and Renovation Recommendations
Once the root cause is identified, adopt thorough, modern construction methods to solve the problem once and for all.
Structural Repairs and Waterproofing Work
For structural cracks, first widen and clean the crack, then fill it with high-elasticity waterproof material or epoxy resin. Add waterproof fabric or non-woven fabric if necessary. Reapply waterproof layers to exterior walls and roofs, such as using elastic cement paint, PU waterproof materials or waterproof mortar. Reapply high-quality waterproof silicone around windows or upgrade to waterproof window systems.
Pipe Replacement and Drainage Optimization
Replace old water pipes entirely with stainless steel or PVC pipes, and ensure joints are securely fastened. Redesign the drainage system with proper slopes to ensure smooth water flow, and clean drains and gutters regularly. For damp areas like balconies or bathrooms, reapply waterproof layers to the floor and add a slope for water drainage to prevent standing water.
Improve Ventilation and Environmental Control
Besides physical repairs, improving the living environment is equally important. Install awning windows, exhaust fans or a heat recovery ventilator to promote air circulation between indoor and outdoor spaces. Use a dehumidifier to control indoor humidity, especially during the plum rain season. Choose mold-resistant and moisture-proof eco-friendly paint for walls to reduce the chance of wall efflorescence recurring.
Old house renovation is a systematic project, and addressing leaks and wall efflorescence is its core. Every step, from accurate detection to selecting appropriate construction methods and materials, cannot be taken lightly. It is recommended to communicate fully with experienced designers and construction teams to develop a complete repair plan, so that old houses can regain their new life and provide safe, long-lasting living spaces.