Who this guide is for
- Homeowners who only see water during storms or from one wind direction
- People preparing to brief a building or envelope professional on an intermittent leak
- Anyone frustrated that a leak hides between rain events
- Owners wanting a weather-linked record before an assessment
Why weather conditions are the key evidence
With wind-driven rain, the path may only open up when rain is pushed sideways against a particular elevation. Recording the wind direction, strength and rainfall when water appears is often what lets a professional reproduce and trace it.
Because the building can be dry the rest of the time, your storm-by-storm log is genuinely irreplaceable evidence.
- Note wind direction during each event
- Record how heavy the rain was
- Note whether it needs both wind and rain
Pinpointing where water appears
Mark exactly where you see water inside — a window corner, a ceiling patch, a wall base, a chimney breast. Note which external elevation that sits behind.
The same internal spot appearing only in south-westerly storms, for example, is a powerful clue, so be precise about location.
Keeping a storm log
Each time water appears, record the date, the weather, the wind direction, where water showed inside, how much, and how quickly it dried. A weather app or local forecast can supply wind direction.
Over a few events the pattern usually sharpens, which is exactly what a professional needs to direct their search.
Photographing the evidence
Photograph the wet area during or just after the storm, with something for scale, and the same spot when dry for comparison. Capture the matching external elevation in daylight too.
Do not climb out in a storm to inspect at height — record from safety and leave external tracing to a professional.
- Shoot wet and dry states of the same spot
- Photograph the external elevation behind it
- Never inspect at height during a storm
Briefing an envelope professional
Bring your storm log, the marked internal locations and matched elevations, and your photos before contacting a building or envelope specialist. Mention which storms triggered it.
Let them trace the path; intermittent leaks are difficult, and your weather-linked record dramatically improves their odds.
Documentation checklist
- 1For each event, record date, rainfall and wind direction and strength
- 2Mark exactly where water appears inside and which elevation is behind it
- 3Note whether both wind and rain are needed, or rain alone
- 4Keep a running storm log across multiple events
- 5Photograph the wet area during or just after the storm
- 6Photograph the same spot dry for comparison
- 7Capture the matching external elevation in daylight
- 8Avoid inspecting at height during storms
Common mistakes to avoid
- Recording only that 'it leaks sometimes' without capturing wind direction and rainfall
- Sealing a suspected spot before a professional traces the actual path
- Logging a single event instead of building a pattern over several storms
- Inspecting outside at height during a storm, which is unsafe
- Assuming the entry point is directly behind the internal stain when water can travel
When to involve a professional
- A building, envelope or roofing professional should trace and address wind-driven rain ingress
- Do not inspect roofs or high walls during storms; working at height in wind is hazardous
- Intermittent leaks can travel far from the entry point, so leave path tracing to a qualified professional
- What causes wind-driven ingress and how it is resolved varies by building, exposure and location
Frequently asked questions
Questions readers ask about this topic
Why does water only come in during storms?
Wind-driven rain can be pushed into gaps that stay dry in ordinary rain, so the path only opens under specific conditions. Logging wind direction and rainfall for each event is what helps a professional reproduce and trace it.
Why record the wind direction?
Ingress that appears only with wind from one direction tells a professional which elevation to focus on. It is one of the most diagnostic details you can capture, so note it every time.
Can I just seal where I see the water?
Water often enters far from where it shows inside, so sealing the visible spot may not address the real path and can hide it. It is more useful to document the pattern and let a professional trace it.
Should I go outside to check during the storm?
Inspecting at height in wind and rain is dangerous. Record what you can see safely from inside, capture the external elevation later in daylight, and leave storm-condition tracing to a professional.
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