Skylight Leaks In Heavy Rain? 5 Common Causes and Solutions

The pitter patter of raindrops on the roof can be a soothing sound. That is, until you notice ominous drips starting to form on your ceiling and realize your skylight is leaking.

Skylight leaks are a common occurrence during heavy rains. As water accumulates on your roof, it will find the slightest gap or weakness in your skylight to seep through. Left unchecked, these leaks can lead to mold, mildew, structural rot, and even serious water damage to your home’s interior.

What Causes Skylight Leaks In Heavy Rain?

There are a few primary causes of skylight leaks when the rains come pouring down:

  • Worn or cracked seals
  • Faulty, improperly installed, or damaged flashing
  • Standing water pooling on the skylight surface
  • Leaks originating in framing or attic before showing up inside
  • Improper previous repairs that failed to address the source of leaks

By understanding what typically causes these leaks, you can correctly diagnose the problem and implement the right solution. Taking a reactive approach by merely dealing with the interior water damage will only lead to leaks recurring in the future.

#1 Cause: Worn Out or Cracked Skylight Seals

The seals around your skylight serve a crucial protective role. Made from weather-resistant materials like rubber or silicone, the seals prevent rain from seeping through the joints and edges of the skylight frame.

skylight leaks when it rains

However, over time these seals can become cracked, brittle and worn due to factors like:

  • Normal wear and tear
  • Exposure to harsh UV rays from sunlight
  • Repeated expansion and contraction from temperature changes

When the seals become compromised, gaps open up that allow rainwater to drip through. Left unaddressed, this constant moisture can quickly cause mold, mildew and rotting of wooden framing.

To fix leaks caused by damaged seals, start by carefully removing all the old sealant with a putty knife. Thoroughly clean the skylight frame and ensure the surface is dry before applying fresh sealant.

Use a high-quality skylight sealant like silicone or polyurethane that will resist degradation from sun and weather. Carefully apply the new sealant around the entire perimeter of the skylight frame, smoothing out any bubbles or gaps.

Allow adequate drying time per the sealant instructions. A freshly re-sealed skylight will prevent leaks during future rains.

#2 Cause: Faulty or Poorly Installed Flashing

The flashing around a skylight serves as the first line of defense against rain. Flashing is a thin, impermeable material, usually metal or roofing felt, that seals the joint between the skylight and roof.

When installed properly, flashing should overlap any seams and completely surround the skylight edges. This creates a watertight barrier that directs water over and around the skylight, keeping it outside where it belongs.

However, faulty or poorly installed flashing with gaps or cracks can allow rain to seep underneath and leak through joints into the attic and ceiling below.

Sometimes previous repairs may have covered up flashing issues without addressing the root cause. This often leads to the leak reappearing after heavy rains.

To remedy flashing problems, start by removing all old flashing around the skylight to expose the base roofing material underneath. Scrape any old roofing cement or debris away.

Cut new flashing at least 8 inches wider than the skylight on all sides. Install the new flashing with proper overlaps, sealing all seams thoroughly with roofing cement. Secure the edges with roofing nails.

Proper flashing installation provides long-term protection against leaks caused by wind-driven rain.

#3 Cause: Water Pooling On The Skylight

As rain collects on your roof, some will inevitably end up on the skylight itself. Most skylights are designed with enough pitch or slope to shed water so it simply runs off the sides.

But flat or poorly draining areas around the skylight can lead to water pooling on the surface. With nowhere to drain, this standing water puts constant hydraulic pressure on the skylight seals.

Given enough time, water will always find the slightest weakness or gap and leak through. Clogged roof drains or debris accumulating on the skylight can also impede proper drainage.

To remedy this issue, try clearing any debris from the skylight itself as well as surrounding drainage channels. Consider hiring a roofer to build up a slope around the skylight to facilitate drainage.

Installing rain diverters or additional drains nearby will also help keep the skylight clear of standing water that could leak through.

#4 Cause: Leaks Originating in Attic or Framing

Sometimes a skylight leak doesn’t originate at the skylight itself. Water can seep in around a vent, through framing cracks or from leaks in the roof valley.

As this water travels into the attic space and along framing, it may emerge in the ceiling below or around the skylight – making it appear that is where the leak started.

This can make leaks very difficult to trace. The actual source could be several feet away from where it shows up in the ceiling below.

Thoroughly testing with a garden hose is key to finding leaks that originate away from the skylight:

  1. Have a friend spray water onto the skylight while you check inside for leaks.
  2. Focus on areas where ceiling seams meet framing around the skylight.
  3. Also inspect framing in the surrounding attic space for drips or moisture.
  4. Removing ceiling panels may help reveal the leak origin.

Tracing water back to its entry point is crucial for a permanent repair. Otherwise, you are just covering up the symptom and the real issue will continue causing leaks.

#5 Cause: Improper Previous Repairs

Many homeowners try quick fixes when their skylight starts leaking, like applying a new layer of caulk or resealing small areas. But these fast repairs often just cover up the real problem temporarily.

If the root cause like damaged flashing or faulty seals isn’t properly addressed, leaks will simply reoccur once heavy rains return.

Previous repairs may also have been well-intentioned but incorrect, like forcing flashing into place without sealing or just sealing over damaged areas.

Taking shortcuts to get a temporary stop to leaks leads to issues popping up again and again. Plus, further interior damage from hidden leaks continues in the meantime.

Be suspicious of any previous repairs that seem like quick band-aids instead of comprehensive fixes. Proper diagnosis of the underlying cause is essential for permanent solutions.

Preventing Skylight Leaks

Once your skylight leak is fully resolved, regular maintenance and inspection will help prevent major issues down the road:

  • Clean debris from skylight and surrounding roof 2-3 times per year
  • Check seals annually and reseal as needed
  • Clear drainage paths around skylight
  • Inspect interior around skylight for any moisture
  • Check attic and framing for hidden water intrusion
  • Replace any cracked skylight glazing

Minor seal or flashing repairs are quick and inexpensive compared to major skylight replacement or water damage repair.

Keep an eye out for any interior dampness, painting bubbling, or musty smells which could indicate leaks. Catching problems early is the key to prevention.

With vigilance and prompt repair, you can keep your skylight providing heavenly views without the worrying drips.

Professional Skylight Repairs

For major flashing issues, skylight replacement, or leaks beyond your repair skills, don’t hesitate to call a professional.

A qualified roofer has the expertise to diagnose and fix even complex skylight leak causes. They have the right equipment and materials to access tricky roof locations and permanently remedy problems.

The cost of professional skylight repairs will vary based on factors like:

  • Accessibility and height of the roof
  • Severity of leaks and water damage
  • Type of skylight and flashing materials
  • Need for full skylight replacement

While a simple resealing may cost around $200-300, large skylight replacement with extensive flashing repairs can run $1000 or more. Get quotes from several roofers before deciding.

Be wary of any roofer who wants payment upfront before completing the full repair. A reputable company will guarantee their workmanship.

With the right repairs, you can once again enjoy the ambiance of a rainy afternoon without worrying about the drips it might bring inside.

Tips for Finding the Leak Source

Locating exactly where your skylight is leaking can be frustrating, but is a critical first step before attempting any repairs. Here are some tips to help track down the source of the leak:

Look For Water Stains

Inspect around the skylight on the interior ceiling and walls. Water stains, blistered paint, or swelling wood are telltale signs of a leak. The stains may not be directly below the skylight if water is traveling along framing before dripping down.

Consider Recent Repairs

Did any roof work or sealing occur prior to the leak? Improper repairs like shoddy flashing jobs often lead to issues later on. Know your skylight’s history to identify potential weak points.

Check the Attic

Go up into the attic and look at the underside of the roof and skylight flashing for moisture or dripping. Dark stains indicate water is entering above and traveling down before showing up inside the home.

Use a Water Hose

On a dry day, have a friend spray water around the exterior skylight while you watch inside with a flashlight. Leaks will show up immediately when water is intentionally applied.

Be Patient

It may take repeated rains before the leak reveals itself. Set up a bucket under suspect areas and inspect after every storm. Eventually the source will become clear.

Emergency Repairs To Stop Leaks Fast

Heavy rain and a skylight leak is a stressful combination. Until permanent repairs can be made, here are some quick fixes to stop the water intrusion:

Seal With Plastic Sheeting

For rainy nights, plastic sheeting taped around the skylight exterior can provide temporary coverage. Use heavy plastic and thoroughly tape to cover all edges.

Plug Flashing Gaps

Inspect the skylight flashing for any openings or lifted areas allowing water under it. Plug these gaps with an emery board, roofing cement, or even chewed gum in a rainstorm pinch.

Divert Water

For standing water or drainage issues, create “rivers” in the roof using duct tape leading away from the skylight. Divert the water to areas that drain properly. Or use towels to soak up pooling.

Add Sealant

If there are any suspected gaps or cracks in the seals, apply clear silicone or roofing sealant as a first line of defense to keep water out. Cover any weeping holes or bolts.

Line The Interior

Place a bucket or tarp below the leak inside to catch drips. Line surrounding areas with towels or absorptive pads. Just stopping interior water damage can provide relief while permanent solutions are arranged.

How To Prevent Skylight Leaks

With some preventative maintenance, you can minimize the chances of pesky skylight leaks occurring when storms strike:

Inspect Annually

Make it a habit to visually inspect your skylight each year prior to rainy season. Check for cracked seals, damage, debris accumulation and ensure flashing is completely intact.

Reseal As Needed

Look for any gaps, tears, cracks or peeling in the skylight sealant and reseal promptly. Full perimeter resealing every 5-7 years can prevent leaks.

Clean Debris

Use a soft brush and mild detergent to clean the skylight glazing and remove any stuck-on debris around the frame, flashing or roofing under the skylight area.

Check Drainage

Clear surrounding gutters and drains to allow proper water runoff. Slope any flat roof sections to prevent pooling around the skylight perimeter.

Preempt Cracks

Inspect the skylight glazing for any small fractures or chips and reseal or replace the pane before cracks have a chance to expand.

Verify Flashing Condition

Make sure metal flashing is free of rust or deterioration. Replace any loose nails orMissing:Opening paragraph doesnt have target keyword “skylight leaks when it rains”

The soothing pitter patter of rainfall can quickly turn into a nightmare when you notice water dripping from your skylight. Skylight leaks during rainstorms are unfortunately very common.

As rain accumulates on your roof, gravity and hydraulic pressure conspire to drive water through the slightest imperfection in your skylight seals or flashing. Left unchecked, these leaks can allow mold, rot, and even serious structural water damage to take hold in your home.

By understanding the most common causes of skylight leaks and learning proper diagnosis and repair methods, you can stop leaks in their tracks and prevent ongoing water damage.

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