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How to Find Where a Leak is Coming From in Your Home

  • Identify ceiling leaks by checking wet spots in the roof space and tracing water trails.
  • Investigate wall leaks by inspecting external cladding, windows, and soffits.
  • Common leak causes: rusted roof, poor flashing, loose fixings, rotten cladding.
  • Window and door leaks may come from inadequate head flashings or lack of seal on the side.

A mysterious water stain on the ceiling or a damp patch on your wall isn’t just a cosmetic issue, it’s often a warning sign of something more serious going on behind the scenes. Left unchecked, leaks can cause costly damage to timber framing, plasterboard, cladding, and flooring.

If you’re trying to track down the source of a leak, here’s how to do it the smart (and safe) way, and when it’s time to call in the pros.

1. Ceiling Leaks: Start from the Roof Space

If you’ve spotted a damp patch or dripping water on your ceiling, particularly after rain, your first move is to head up into the roof space (if accessible).

If your home has trusses (not rafters), this makes it easier to access and move around the ceiling space.

Here’s what to do:

  • Locate the wet area of the ceiling lining inside your roof space.
  • Look upwards to find where water is dripping or running down.
  • Trace the moisture trail back to its highest point, that’s usually close to where the leak is originating.

Common causes of ceiling leaks include:

  • Rusted or cracked roofing iron
  • Loose or missing roofing screws/nails
  • Damaged or poorly installed flashing around chimneys, valleys, or skylights
  • Blocked or overflowing gutters causing water to back up under roofing

If you’re unsure what you’re looking at, or it’s unsafe to access, stop and call a qualified builder or roofer.

2. Wall Leaks: Inspect Outside First

A leak showing up on your internal wall can be tricky, but a good rule of thumb is this: Water almost always travels downward. That means the source is often higher than where the damage is showing.

Steps to investigate:

  • Go outside and inspect the external wall where the leak appears inside.
  • Look for obvious signs of water entry such as:
    Damaged or cracked cladding
  • Gaps near windows, doors, or penetrations (vents, pipes, etc.)
  • Rotten timber or swollen boards
    Loose or deteriorated flashing under the soffit
  • Pay particular attention to roof junctions, soffits, and cladding transitions above the affected area.

Leaks on walls can be caused by:

  • Inadequate or missing head flashings above windows and doors
  • Unsealed gaps in the side of the windows or doors (unsealed scriber, no inseal foam or silicon behind window extrusion if on flat cladding)
  • Poor corner detailing (e.g. poorly made box corners, no flashing behind corners)
  • Holes in cladding
  • Rotten or aged cladding allowing water ingress

3. Understand What Typically Causes Leaks in NZ Homes

With New Zealand’s varied climate and heavy rainfall, homes here face serious exposure to the elements. These are typically the most common culprits behind home leaks:

  • Rusted roof sheets or decramastic tiles (especially on older homes)
  • Broken roofing tiles
    Roofing screws or nails not fastened correctly
  • Incorrectly installed or failing flashings
  • Poorly sealed head flashings and sides of joinery
  • Rotten timber cladding or broken weatherboards
  • Missing or poorly executed building wrap and waterproofing
  • Lack of flashing in vulnerable corners or transition points

Most leaks occur not because of one big failure, but from small details being missed during construction or repairs. That’s why it pays to work with licensed builders who know the building code inside and out.

4. When to Call in a Professional

While it’s helpful to investigate yourself, some leaks require a trained eye. The small visible part of the leak may be a sign of far greater damage which could require licensed building work to be carried out.

Call Villaworx Construction. We can identify the source, recommend practical solutions, and carry out repairs to stop the damage at the source and any additional work required to make your home safe and sound.

Tracking down a leak isn’t always straightforward, water can move in unpredictable ways, especially behind walls or roofing. But with the right approach, you can narrow it down and take action before further damage sets in.

Need help with a roof or cladding leak?

Get in touch with our expert team and let’s sort it before it gets worse.

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