Key Takeaways
Most skylights that appear to be leaking are not leaking through the glass. Water is entering at the flashing, the curb or the roof plane above the unit.
Condensation and a genuine leak look almost identical from inside, and telling them apart determines whether you need a skylight repair or a ventilation correction.
A skylight installed before roughly the year 2000 has almost certainly outlived its seals and gaskets, and reflashing a worn out unit is money spent twice.
The right time to open a skylight curb is a dry week, which in Clark County means now rather than in November. HOMEMASTERS Vancouver serves Camas, Washougal, Brush Prairie, Battle Ground and Hazel Dell. Free written estimates. Call (360) 836-4100.
Get a diagnosis from HOMEMASTERS Vancouver Washington State Labor and Industries licensed, bonded and insured, CertainTeed ShingleMaster certified, with W-2 employee crews rather than subcontractors. Call (360) 836-4100.
The stain on the ceiling around your skylight is probably not the skylight’s fault. That is the most useful thing to know before you call anyone, because it changes what you should be asking for. Skylight glass units very rarely fail in a way that admits water. What fails is the flashing kit around the unit, the sealant at the head and sill, the curb the unit sits on, or the roof plane immediately upslope that is dumping water into a detail never designed to handle that volume.
Camas has a particular version of this problem. The older neighborhoods carry craftsman and mid century homes where skylights were retrofitted into roofs that were never framed for them, and Southwest Washington gives those retrofits sustained moisture for seven or eight months a year rather than short intense storms. Slow, patient water finds every shortcut a previous installer took.
Why is my skylight leaking?
In most cases water is entering at the flashing rather than through the skylight itself. The usual causes are failed sealant at the head flashing, step flashing that was reused rather than replaced during a previous reroof, a curb that has rotted from the top down, debris damming water above the unit, or condensation being mistaken for a leak. A proper diagnosis identifies which of these is happening before any material is ordered.
Leak or condensation? Tell them apart first
This single distinction saves people a great deal of money, and it is easy to check.
A leak follows the weather. Water appears during or shortly after rain, it tends to arrive at one specific point, and it often leaves a defined stain with a hard edge. Condensation follows temperature. It appears on cold clear nights and on mornings after a cold night, it forms evenly around the glass perimeter and the lower frame, and it is worst in kitchens, bathrooms and laundry rooms where humidity is generated.
If your skylight weeps on a cold dry January morning and stays dry through a November downpour, you do not have a roofing problem. You have a ventilation and humidity problem, and the fix is balanced attic ventilation and better moisture control inside the house. Replacing the skylight will not change it.
The four places water actually gets in
1. Head flashing and the roof plane above
The head flashing at the top of a skylight diverts water around the unit. When a skylight sits below a long roof run, or below a valley, that flashing is handling far more water than a standard detail anticipates. Under the maple and fir canopy common in Camas, the head detail also collects leaf and needle debris, which dams water and holds it against the seam.
2. Step flashing along the sides
Side flashing is a stepped assembly, one piece per shingle course. Every reroof is an opportunity to reuse it rather than replace it, and reusing it is the single most common cause of a skylight leak that starts one to two years after a roof was replaced. Correct practice is new flashing with every new roof.
3. The curb
Curb mounted skylights sit on a wooden frame built up from the roof deck. In sustained wet conditions the curb rots from the top edge downward, often invisibly under the flashing. Once the curb is soft, no amount of sealant will hold, because there is nothing sound to seal to.
4. The seals and gaskets in the unit
This is the least common cause and the one people assume first. Insulated glass units do eventually fail, and the symptom is fogging or moisture between the panes rather than water running down the frame. A fogged unit is a glazing failure, not a leak.
Not sure whether your skylight needs reflashing or replacing? Call HOMEMASTERS Vancouver at (360) 836-4100 for a free written estimate with no pressure and no obligation. See service details on the Vancouver location page.
Repair or replace: how to decide
Reflash and reseal when the unit itself is sound, the glass is clear, the frame is solid and the curb is dry. This is the right answer for a skylight under roughly fifteen years old with a flashing failure.
Replace the unit when the curb is soft, when the glass is fogged, when the unit predates roughly the year 2000, or when the roof is being replaced anyway. The labor to open a skylight curb is most of the cost of the job. Doing that labor twice, once to reflash an old unit and again in three years to replace it, is the expensive path.
Always replace during a [roof replacement](https://homemasters.com/services/roofing/). New shingles around an old skylight is a false economy, and most flashing failures trace back to exactly that decision made on a previous project. See the full [skylight service](https://homemasters.com/services/skylights/) scope for what a correct installation includes.
What correct installation looks like
A correct skylight installation uses the manufacturer’s own flashing kit rather than a generic assembly, replaces all step flashing, carries ice and water shield up the curb and onto the deck around the opening, and finishes with a head detail that diverts water around rather than into the seam. Deck mounted units on low slope roofs need particular attention, because low slope means water moves slowly and stands longer.
Modern units also solve a problem older ones caused. Skylights installed in the 1980s and 1990s were frequently a net energy loss. Current low emissivity glazing and insulated frames behave much more like a good window, which matters through a Clark County winter.
Frequently Asked Questions
Why is my skylight leaking in Camas, Washington?
In most cases water is entering at the flashing rather than through the skylight. Common causes are failed sealant at the head flashing, step flashing reused during a previous reroof, a rotted curb, or debris damming water above the unit. Call HOMEMASTERS Vancouver at (360) 836-4100 for a written diagnosis before any material is ordered.
How do I tell a skylight leak from condensation?
A leak follows the weather and appears during or shortly after rain, usually at one defined point. Condensation follows temperature, appears on cold mornings, and forms evenly around the glass perimeter and lower frame. If moisture shows up on cold dry mornings and not during rain, the issue is attic ventilation and indoor humidity rather than the roof.
Should I repair or replace my skylight?
Reflash and reseal when the unit is sound, the glass is clear and the curb is dry, which usually applies to skylights under roughly fifteen years old. Replace the unit when the curb is soft, the glass is fogged, the unit predates roughly the year 2000, or the roof is being replaced anyway. Most of the cost is the labor to open the curb, so doing it twice is the expensive path.
Can a skylight be replaced without replacing the whole roof?
Yes. A skylight can be replaced independently, and the surrounding shingle courses are removed and reinstalled to allow correct flashing. The reverse is not recommended. Installing a new roof around an aging skylight is the most common cause of a leak that appears one to two years later.
When is the best time of year for skylight work in Clark County?
Dry weather, which in Southwest Washington means late summer through early autumn. Opening a roof curb requires a dependable dry window, and sealants and flashing tapes bond properly at warmer temperatures. Call (360) 836-4100 to check current scheduling.
Get a free written skylight assessment in Camas HOMEMASTERS Vancouver provides free written estimates with no obligation across Camas, Washougal, Brush Prairie, Battle Ground and Hazel Dell. Call (360) 836-4100 or visit the Vancouver location page to request a visit.
