How to Identify and Repair Stucco Window Leaks
Experiencing leaks around stucco windows can be concerning for homeowners. As certified professionals in stucco repair and window installation, we at Stucco Champions want to help you understand how to diagnose and fix these issues effectively.
Determining the Source of the Leak
The first step is figuring out whether the leak comes from the window itself or from the surrounding stucco system. This distinction is crucial because it determines whether the window or the stucco assembly requires repair.
Testing for Leaks
Interior Inspection
Remove the interior drywall around the window to check the plywood or OSB (oriented strand board) and framing. This provides a clear view of water intrusion.
Window Test
Seal the window’s face with waterproof tape and cover it with thick plastic. Spray water onto the setup. If water still gets in, the issue likely lies in the stucco or flashing, not the window itself.
Alternative professional methods include infrared thermography and water spray tests.
Common Causes of Leaks
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Flashing Issues
Improper or deteriorated flashing is one of the most frequent causes of leaks. Flashing is the thin metal or waterproof material that directs water away from windows. When installed incorrectly, water penetrates and damages underlying wood. -
Stucco Paper Deterioration
Stucco paper (also known as weather-resistive barrier or WRB) acts as a moisture barrier. When damaged or deteriorated, it can allow water into the wall system.
Learn more about weather-resistive barriers from the International Code Council (ICC).
Temporary Fix: Caulking
Caulking around the window can seal small cracks, but this is only a short-term solution. Long-term water intrusion can still damage the framing and stucco layers.
Comprehensive Leak Repair
If the problem lies in the stucco or flashing, a full repair may involve:
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Removing 6–9 inches of stucco around the window
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Inspecting and repairing or replacing flashing
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Installing new stucco paper (WRB)
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Re-stuccoing with proper finish and color match
Depending on the stucco system—whether it’s traditional three-coat, one-coat, or EIFS (Exterior Insulation and Finish System)—repair methods and materials will vary.
Cost Expectations
Costs for stucco window leak repair usually range between $400 and $1,800+ depending on:
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Window size and accessibility
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Presence of decorative trim or custom finishes
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Type of stucco system (three-coat, one-coat, or EIFS)
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Color matching requirements
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Severity of damage and structural repairs needed
For example, homes in regions with higher labor costs, such as California, may lean toward the higher end of this range.
Preventing Future Leaks
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Regular Maintenance: Inspect windows and stucco annually for cracks or caulking deterioration.
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Professional Inspections: Schedule a stucco inspection every 3–5 years for early detection.
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Proper Installation: Ensure flashing and WRBs are installed correctly during construction or window replacement.
Transparency and Product Recommendations
All recommendations here are based on our field experience. We do not endorse any brand for profit. Any affiliate links are clearly disclosed for full transparency.
Conclusion
Identifying and repairing stucco window leaks requires a systematic approach. Whether it’s a simple caulking fix or a full flashing replacement, understanding the root cause ensures the repair lasts. Regular maintenance and inspections go a long way in protecting your home.
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Contact Stucco Champions today for a free consultation!
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