Diagnosing a Leaking or Failing Skylight

A leaking skylight almost always traces back to worn flashing, a failed seal, or condensation, not a cracked pane like most folks assume. Ashburn's housing stock from the 1990s and 2000s means a lot of original skylights are now well past the age where seals start to give out. Catching the real cause early saves the ceiling drywall underneath.

According to experts at VELUX, a brown ring on the ceiling doesn't always mean your skylight itself is broken. It's often the flashing around it, not the glass. Flashing is the metal strip that seals the skylight to your roof.[1] Once it corrodes or shifts, water finds a way in during hard rain:

• A stain or drip line on the ceiling below the skylight, especially after wind-driven rain
• Fogging or condensation between the glass panes that won't clear up
• Cracked or curling caulk around the frame you can see from inside the attic
• A musty smell in the room even when there's no visible water

Here's something we run into a lot in Ashburn. Many homes here were built during the big development years of the 1990s and 2000s. Their original skylights are now over 20 years old. That's right around the age when seals and flashing start to fail. So if your house was built during that boom, and the skylight has never been touched, age alone could explain the problem.

Condensation gets blamed for a lot of things it didn't cause. It shows up as fog between the panes. It's usually a sign the seal has broken down, not proof of an active leak.

Not sure which one you've got? That's common, and it's hard to tell from the ground. A quick look from inside the attic or from the roof usually settles it fast.

Skylight Installation in Ashburn: Is Your Roof a Good Candidate

Not every roof is ready for a skylight. Some are perfect candidates. Others need work first, and a few just aren't a good fit. We get asked about this constantly in homes built during the 1990s and 2000s boom around Ashburn Village and Broadlands, where vaulted family rooms and steep-pitched roofs are everywhere.

A steeper roof pitch drains water fast and gives us clean flashing lines. This is what a skylight needs to stay leak-free for years. Low-slope or nearly flat roofs are trickier. Water sits longer near the frame. We have to use different flashing methods and sometimes recommend a curb-mounted unit instead of a flush deck-mounted one:

• Roof pitch of roughly 3:12 or steeper, generally easier and more reliable to flash
• Clear attic space between the rafters where the shaft will run, no ductwork or wiring in the way
• Roof covering with useful life left, not curling shingles or a deck close to replacement
• No history of leaks or soft spots near the planned skylight location
• Enough rafter spacing to avoid cutting into structural framing

If your roof is due for replacement in the next couple years, hold off. We'd rather install the skylight during a new roof project. It saves you money and avoids tearing into fresh shingles twice.

So how do you know for sure? A quick look in your attic and a walk on the roof usually tells us everything we need.

Repair, cleaning, or full replacement? Find out which one your skylight needs.

When Skylight Repair or Cleaning Beats Full Replacement

Not every cloudy or dripping skylight means you need a whole new unit. We get calls from Ashburn homeowners who see a foggy dome and jump straight to thinking about replacement. A lot of the time, that's not where we end up.

Often, a hazy skylight is just condensation trapped between the panes, not a failed seal on the roof. A small drip during a windy storm doesn't always mean the flashing failed.

Here's what usually points to a repair or a good cleaning instead of a full swap out:

• Cloudy or hazy glass with no water stains showing up on the ceiling below
• A drip that only shows up during heavy, wind-driven rain
• Flashing that still looks solid, just dried out or cracked caulk around the edges
• A unit under about 10 years old with no cracked or fogged glass panels

Not sure which one describes your skylight? That's common, and it's why we look before we ever quote anything.

That's usually a repair job, not a replacement.

So, if your skylight is still tight, still sealed, and just needs a fresh bead of caulk or a good scrub inside and out, we'll tell you that straight. Our team would rather earn your trust on the small job than push you into a bigger one you don't need yet.

How Professional Skylight Installation Works, Step by Step

Cutting a hole in your roof sounds scary. It shouldn't be, once you see how the process goes.

We treat every skylight job the same way, whether it's a small fixed unit over a hallway or a bigger vented one for a primary suite. Here's the order we follow every time:

• We check the attic space and rafters first. This tells us if we're working with trusses or standard framing, and it changes how we frame the opening.
• We mark the roof opening from inside and outside so both lines match exactly.
• We cut the roof deck and remove the section of shingles or roofing material in that spot.
• We build out the frame with headers and jack rafters to carry the load properly.
• We set the skylight unit into the opening and secure it to the frame.
• We install step flashing and counter-flashing around all four sides so water has nowhere to go but off the roof.
• We finish the interior with drywall, trim, and a light well if the ceiling sits above the roof deck.

That flashing step matters more than people realize. A leaky skylight isn't a bad unit, it's flashing that was rushed or skipped. We're licensed as a Virginia Class A Contractor, and we pull the permits when the job calls for it, so nothing gets skipped on paper either.

Weather plays a role too. In Ashburn, we try to avoid starting a skylight cut when rain is moving in within 24 hours, since the roof stays open during framing and flashing.

Most straightforward installs finish in a day. Ones that need new framing or a light well through an attic space can take longer.

What Drives Skylight Installation Cost

So, what actually changes the price on a skylight job? A lot more than the skylight itself. The unit is just one piece of the puzzle.

Roof pitch matters. A steep roof takes longer to work on safely and needs more setup time. Roof material matters too; asphalt shingle and metal roofing call for different flashing methods. Then there's the ceiling underneath. If you've got a flat ceiling with attic space above, we're building a light shaft down through the framing. That's more carpentry, more drywall work, more time on the ladder:

• Whether it's a new roof penetration or a replacement of an existing skylight
• Roof pitch and how steep the access is
• Flashing kit type needed for the roofing material
• Ceiling shaft framing for attic spaces versus vaulted ceilings
• Electrical work if the unit is solar powered or vented
• Drywall and paint finishing around the interior opening

Around Ashburn, we run into a lot of homes with vaulted ceilings in the family room. There's no attic space to hide the work in. That's actually the simpler install in some ways — a straight shot from roof to ceiling, with less framing involved.

Before you get quotes, ask a few questions. Ask what the flashing kit is made of. Ask if the price includes interior drywall finish or just the roof work. Ask if they're pulling a permit. Those answers tell you more than the bottom-line number ever will.

See what actually drives the cost once framing, roof pitch, and ceiling shafts get involved.