VELUX windows are roof windows that fit particularly well in rooms such as lofts and rooms with pitched roofs. These vertical windows let in more natural light, enhance roof ventilation, and are a great addition to your home.

As with any windows, if you notice any problems such as water coming in during wet weather, it’s important to address the problem promptly to prevent further damage.

In this article, we look at how to identify the problem area and source of the leak, common causes of VELUX window leaking, and how to fix the problem.

Identifying the Source of the Leak

Identifying leaking VELUX windows is important to prevent leaks and potential damage.

To identify the source of the leak:

  • Look for water stains, dampness, or visible drips near the leaking window.
  • Inspect the exterior for damaged roofing, roof tiles, or gaps around the frame.
  • Check the seal for wear and tear, and examine the interior for water damage.
  • During heavy rain, observe the window for leaks. If the VELUX windows leaking continues, check the window flashing for gaps.

Common Causes of VELUX Window Leaks

Common causes of a leaking VELUX window include:

  • Faulty installation or maintenance.
  • Damaged flashings.
  • Damage to the roof structure.
  • Humidity levels and internal condensation.

Fixing VELUX Window Leaks: A DIY Guide

Fixing VELUX roof windows yourself can save you time and money. Here are some DIY methods you can follow, with safety in mind:

  1. Prioritise Safety:
    • Wear protective gear, such as gloves and safety glasses.
    • Use a stable ladder with assistance. Make sure you have someone on hand to help you.
    • Be aware of any electrical cables near the window frame.
  2. Check the Exterior:
    • Inspect to see if you have a damaged roof. Even damage to a single tile could cause a problem in bad weather conditions, such as a leaking roof or roof window.
    • Seal any gaps around the window with caulk.
  3. Roof Repair:
    • Replace any missing shingles. You may want to consult a local roofer to ensure this is installed correctly.
  4. Inspect the Seals:
    • Check for worn or torn window seals, replacing these where necessary.
  5. Check the Interior:
    • Repair any interior damage with waterproof filler.
  6. Inspect the Flashing:
    • Seal any gaps in the outer flashing with roofing cement or tape.
  7. Adjust the Window Seal:
    • Ensure proper alignment and adjust if needed.
  8. Condensation Control:
    • Improve ventilation and consider a dehumidifier to prevent condensation.
  9. Gutter Maintenance:
    • Clean your gutters regularly and ensure proper drainage.
  10. Roof Slope Correction:
    • Consult a professional for a structural assessment.

If you decide to attempt any repairs yourself, always prioritise safety and seek professional help if you are unsure. Cosyhomes Windows offers a range of window repairs and can advise you on the best course of action.


Regular maintenance is crucial to avoid future issues. Consider seeking skilled experts like Cosyhomes Windows for professional inspections and repairs. Regular care enhances the lifespan of your VELUX window and safeguards your home against water damage, ensuring your roof window remains in good condition.