Spring on Vancouver Island is beautiful, but it’s also when a lot of hidden roofing problems start showing up.
Skylight leaks in spring are one of the most common calls we get. Vancouver Island winters are relentless on roofing materials. Months of rain, freeze-thaw cycles, coastal wind, and moss accumulation all do quiet damage to the areas around skylights. By the time spring arrives, the real test begins. And for a lot of homeowners, that test shows up as a water stain on the ceiling.
Water damage rarely stays small for long.
A slow drip through a compromised skylight seal, left alone through a BC summer with its late-season storms, can become a mould problem, a framing problem, or a full interior renovation. Catching it in May or June changes that outcome entirely.
This article walks through how to identify whether your skylight is actually the source of the leak, what’s usually causing it, and what a repair actually involves, including when it makes sense to fix it yourself versus when to call someone in.
Why Skylights Tend to Leak in Spring
Skylights sit at the intersection of two materials (glazing and roofing membrane) and that junction is where problems develop. Winter puts stress on both. When temperatures fluctuate between freezing and mild, which is basically every Vancouver Island winter, the flashing and sealant around the skylight expands and contracts. Over time, that movement creates micro-gaps. Spring rain is the first real test of whether those gaps matter.
A few other reasons spring brings leaks to the surface:
- Moss and debris that built up over winter can dam water around the skylight base, forcing moisture under the flashing
- UV exposure increases in spring and accelerates the degradation of older sealants and caulking that were already borderline
- Higher rainfall in early spring means more water volume sitting against vulnerable seals for longer periods
- Any flashing that lifted or shifted during winter will show its weakness the first time it rains hard
Most spring skylight leaks are manageable if they’re caught early. The problem is many homeowners don’t notice them until water stains appear inside, by which point moisture has usually been sitting in the insulation and framing for a while already.
How to Tell If Your Skylight Is Actually Leaking
Not every stain near a skylight is caused by the skylight. And not every drip on cold mornings is a leak. Getting this wrong wastes money on repairs that don’t solve anything.
Signs Inside the Home
- Water stains on the ceiling or drywall around the skylight frame, especially if they appear or grow after rainfall
- Peeling or bubbling paint near the skylight well
- A musty smell in the room below, even without visible water
- Condensation on the interior glass that doesn’t clear. This usually points to a failed seal within a double-paned unit, not a roof leak
- Soft, warped, or discoloured wood around the skylight frame
Signs From Outside
If you can safely see your roof from the ground or a window:
- Lifted, cracked, or missing flashing around the skylight curb
- Cracking or shrinking caulking at the edges of the frame
- Moss or algae growing directly around the skylight base
- Visible gaps where the frame meets the surrounding shingles
Condensation vs. an Actual Leak
Condensation shows up on the glass surface during cold weather and typically clears as the room warms up. An actual leak produces water in the same spot every time it rains, often on the ceiling or wall rather than on the glass itself, and leaves staining even after it dries.
If you’re not sure which you’re dealing with, go into the attic during or right after heavy rain. Check the insulation and framing around the skylight curb with a flashlight. Active dripping or wet insulation near the base confirms the skylight is the source. If the moisture appears several feet away, the water is likely traveling along a rafter from somewhere else on the roof entirely.
What’s Usually Causing It
Failed Flashing
This is the most common culprit. Flashing (the metal sheeting that seals the transition between the skylight curb and the roof surface) lifts, cracks, and pulls away over time. Even a small gap is enough. On a Vancouver Island roof that’s been through a few wet winters, flashing issues are almost expected on any skylight older than 10 years.
Cracked or Dried-Out Sealant
Roofing sealants have a lifespan of roughly 5 to 10 years depending on UV exposure and climate. Once they shrink or crack, water finds its way in. This is one of the most overlooked maintenance items on residential roofs, not because it’s hard to fix, but because most homeowners don’t know to check it.
Aging or Cracked Glazing
Older polycarbonate skylights (common in homes from the 1980s and 90s) become brittle over time. If the glazing itself is cracked, no amount of flashing work will stop the leak. These typically need a full unit replacement.
Poor Original Installation
Skylights added during renovations, especially by non-roofing tradespeople, are sometimes installed without proper step flashing, counter flashing, or adequate underlayment. These tend to leak eventually no matter how well the original job looked.
Debris and Moss Buildup
Pine needles and moss accumulate at the base of skylights and act like a sponge, holding moisture against the flashing and sealant long after the rain stops. On a wooded Vancouver Island property, this is worth checking every fall and spring.
DIY vs. Calling a Roofer: Where the Line Is
Some maintenance tasks around a skylight are genuinely manageable without getting on the roof. Others aren’t.
What You Can Handle From the Ground or Inside
- Cleaning moss and debris away from the skylight base with a soft brush and a moss treatment product
- Checking interior framing with a flashlight during or after rain to confirm the source
- Protecting your interior (towels, containers, plastic sheeting) while you arrange a repair
- Documenting the water entry point with photos before it dries
When to Call a Professional
Get a roofer involved when:
- The roof is wet, steep, or you don’t have safety equipment
- The leak is active and getting worse
- You can see cracked or lifted flashing from the ground
- The skylight is more than 15 to 20 years old
- You’ve already tried resealing it and the leak came back
- There’s visible damage to interior framing, drywall, or insulation
Walking on a wet roof without proper footwear and anchor points causes serious injuries every year. The repair cost is almost always less than the alternative.
What a Professional Skylight Repair Actually Involves
When a roofer comes out to assess a skylight leak, the first job is always source identification, not just resealing whatever looks worn. Water travels, and repairs made in the wrong location will fail.
From there, the scope depends on what’s found:
- Flashing repair or replacement: If flashing is the issue, it will be re-bedded and sealed if it’s still structurally sound, or removed and replaced with new step and counter flashing if it’s not. This isn’t a sealant-over-the-top job. Proper flashing installation is skilled work.
- Resealing: Fresh exterior-grade sealant or caulking applied to the frame. Applying new sealant over old cracked material without removing it first is the most common DIY mistake. The new product won’t bond and the leak returns.
- Full replacement: If the glazing is cracked, fogged (indicating a failed double-pane seal), or the unit is simply at end of life, replacement is usually the more cost-effective long-term option. A new skylight with proper flashing should give you 20 or more years.
Realistic Repair Costs for Vancouver Island Homeowners
Cost ranges in the Canadian market for skylight-related repairs:
- Reseal and minor flashing repair: $150 to $400 depending on accessibility and time on site
- Full flashing replacement: $400 to $900 depending on skylight size and complexity
- Full skylight replacement (supply and install): $1,200 to $3,500 or more depending on unit size and roof complexity
- Interior repairs (drywall, insulation, paint): Variable, but this is exactly what early intervention prevents
A $200 reseal in May can prevent a $2,000 interior repair by September. We see that math play out constantly.
Common Questions About Skylight Leaks
Can a roofer fix a skylight leak in one visit?
Usually, yes. Most skylight leak repairs are straightforward once the actual source is identified. Flashing repairs and reseals are typically completed the same day. Full replacements may require scheduling around material lead times, but that’s not the norm for most repairs.
My skylight only leaks in heavy rain, not light rain. Why?
Light rain doesn’t produce enough volume or pressure to breach a small gap, but heavy rain does. It’s a classic sign of a flashing or sealant issue. The gap exists in both cases, it just takes a certain water volume to push through. Flat-roof skylights with any standing water tendency are especially prone to this pattern.
What products are best for sealing a skylight leak?
For minor maintenance, a polyurethane roofing sealant (brands like Tremco or NP1 are common in BC) is more durable than standard silicone. Butyl-based flashing tape is useful as a temporary measure over small flashing gaps. But if the sealant failure is more than minor surface cracking, having a roofer assess it first is worthwhile. Applying fresh product over deteriorated flashing doesn’t address the underlying issue.
Does insurance cover skylight leaks?
It depends on the cause and your policy. Sudden storm damage (a fallen branch that cracks the glazing, for example) is often covered. Gradual deterioration from age and deferred maintenance generally isn’t. Document the damage thoroughly with photos and review your policy before filing anything.
How long does a repaired skylight last?
A properly repaired unit (new flashing, quality exterior sealant, debris kept clear) should last another 10 to 15 years with routine checks. A full replacement typically runs 20 years or more, depending on the unit quality and how well the installation was done.
Catch It Before Summer Storms Do
A small skylight leak in May is a repair. Left alone through a Vancouver Island summer, with its August and September storm runs, it becomes insulation damage, potentially framing damage, and the kind of interior work that involves cutting into drywall.
If you’ve noticed staining around your skylight, dripping during heavy rain, or condensation that seems to reappear after wet weather, it’s worth having someone take a look before the problem spreads. The Roof Pro serves homeowners across Central Vancouver Island, including Nanaimo, Parksville, Qualicum Beach, and surrounding areas. We can inspect the issue, give you a straight assessment of what’s actually going on, and repair it before it turns into something more expensive.
Contact The Roof Pro to book a skylight inspection.
Visit theroofpro.ca to get in touch.