How Do I Know If My Skylight is Leaking?

Detect skylight leaks early to prevent water damage. This article helps you to learn the common signs, DIY inspection methods and when to call a professional roofer or contact your roof window supplier.

Table of Contents

1. Water Stains on Ceilings or Walls

What to Look For:

• Yellowish-brown spots or rings near the skylight, often spreading gradually.
• Stains may appear days after rain due to water traveling along roof beams before dripping.
• Tip: Use a moisture meter to check if the area is actively wet (readings >20% indicate moisture issues).

2. Mold Growth

Why It Happens:

• Leaks create damp environments which is easy for mold (often smells musty).
• Check attic spaces above the skylight for black or green patches on wood or insulation.
• Warning: Prolonged mold exposure can cause respiratory issues. You need to address leaks ASAP.

3. Damp Insulation or Sagging Wall

Signs:

• Wet, compressed insulation around the skylight frame.
• Sagging or warped drywall below the skylight.
• Risk: Wet insulation loses R-value. This will increase your energy bills and increase rot risks.

4. Visible Light or Water During Rain

Test During a Storm:

• Turn off lights and observe daylight streaming through gaps in the frame (indicates seal failure).
• Look for dripping water along the glass edges or frame joints.
• Pro Tip: If rain is light, use a garden hose to spray the roof around the skylight (simulate heavy rain).

5. Drafts or Temperature Changes Near the Skylight

What It Means:

• A drafty skylight may signal cracks in seals or flashing, allowing air and moisture to enter.
• In winter, ice dams near the skylight could indicate heat loss, leading to leaks.

6. Cracks in Framing or Flashing

Exterior Inspection:

• Check the skylight's metal flashing for rust, gaps or peeling sealant.
• Look for cracks in the window frame (common in aging vinyl or wood frames).
• Key Area: The area where the skylight meets the roof, it is a prime spot for water infiltration.

7. Peeling Paint or Wallpaper

Inside the Home:

• Bubbling or peeling paint or wallpaper near the skylight often indicates slow, and persistent leaks.
• The damage may appear far from the skylight if there is water.

DIY Inspection Steps for Skylights

Step 1: Check the fixed skylight window

• Inspect the skylight's underside for water stains, rust or wet insulation.
• Feel around the frame for dampness (wear gloves to avoid mold).

Step 2: Examine Exterior Flashing

Use a ladder to inspect the roof (safety first!). Look for:

• Cracked sealant around the skylight.
• Missing or damaged roof shingles or tiles near the skylight.
• Corroded flashing joints (common in older homes).

Step 3: Perform a Water Test

On a sunny day, spray the skylight and surrounding roof with a hose for 5–10 minutes.

Check indoors for leaks immediately after and 30 minutes later (some leaks are slow).

When to Call a Professional Roofer or Contact the Roof Window Skylights Manufacturer?

Contact them if you notice:

• Major structural damage like sagging ceilings.
• Multiple leaks or recurring mold after DIY fixes.
• Skylights older than 15 years (seals degrade over time).

Conclusion

Early detection on skylight water leaks is key to preventing expensive roof window repair or replacement costs. Regularly inspect for stains, mold and flashing damage and don't hesitate to call a professional roofer or your fixed skylight window supplier for complex issues. With proper maintenance, your skylight system can perform well for years.

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More resources:

Fixed Skylight Window -- Source: Baibian

Commercial Roof Windows -- Source: Baibian

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