A wet ceiling under a skylight is not one problem, it is about six different problems that all look the same from the floor. Answer the questions below the way you would describe it on the phone and you will get the most likely cause, whether it is usually a repair or a replacement, and the exact photos to send so somebody can price it without guessing.
This is the same sequence we go through on an inbound call. It is not a substitute for somebody getting on the roof, and we say so plainly in the result. It is here so you walk into the conversation knowing what you are probably dealing with.
It is condensation, not a leak. Water on the inside face of the glass on a cold morning with no rain, or a damp ring that dries out by afternoon. A skylight is the coldest surface in the room and humid indoor air gives up its water there. Common in kitchens, bathrooms and in any room that has been shut up. Fixing it is ventilation and sometimes a better glazed unit, not roof work. We say this to people regularly and it saves them a job they did not need.
The seal in the glass has failed. A permanent haze or a milky film between the two panes that you cannot wipe off, sometimes with a visible water line. The insulated glass unit has lost its seal. Nothing is leaking into the house. On a modern unit the glass can sometimes be swapped on its own. On an older one the sash is usually the cheaper answer.
The flashing is letting water in. Staining on the ceiling a foot or more away from the opening, or only when rain is being driven sideways. Water almost never comes through the middle of the glass. It gets in where the skylight meets the roof, which is step flashing on a shingle roof and a base and counterflashing on a flat one. This is the most common real leak and it is usually a repair.
The curb has gone. Water showing up a long way from the skylight, a floor or two below, or down a wall, often on a unit over twenty years old. The curb is the box the skylight sits on. Wood rots and masonry curbs lose their parging and their cap. The unit above it can look perfect. This is the one that is almost always worse than it looks from inside, and it is the one people are most often quoted wrong on, because a new skylight on a bad curb leaks again.
The unit is simply finished. Plastic domes go cloudy, yellow and then crazed with hairline cracks, and once a dome is crazed it is at the end of its life. Old galvanized steel frames with wire glass rust from the inside of the frame outward, and the glazing putty that held it was never meant to last this long. Both are replacements, not repairs, and we would rather tell you that than sell you a sealing.
Water is backing up over the top of it. Leaks that only show up after snow sits, or after a long soaking rain rather than a short hard one. Either ice is damming above the skylight and standing water is getting under the flashing, or the roof drain or the field of the roof is holding water. The skylight is the place it finds, not the reason it is there. Fixing the skylight alone will not fix this.
Four photos get a skylight priced properly more often than anything else, and they are the reason this page exists. Email them to info@nyskylightinstallers.com or send them through the contact form.
1. From back far enough to see the roof around it. Stand ten or fifteen feet away if it is safe to. We need to see what the roof is made of, how close the skylight sits to a parapet or a valley, and whether anything upslope is dumping water onto it.
2. Straight down on the curb. The joint between the skylight frame and the roof is where the answer usually is. Get the whole perimeter if you can.
3. The glass or the dome, up close. Fogging between panes, crazing, cracks and old putty all read clearly in a close photo and they decide repair against replacement.
4. The inside. Point up at the opening from the room below and include the stain. Where the stain sits relative to the opening is what separates a flashing problem from a curb problem.
If there is a data plate or a sticker on the sash, photograph that too. On a VELUX it gives the exact model and size and we can look the whole unit up from it.
Please do not get on a wet or a steep roof to do this. Shoot what you can from a window, a bulkhead door or the ground. We will get the rest ourselves.
Flashing problems, a loose or bound venting mechanism, a failed gasket and a dirty rain sensor are repairs, and on a unit that is otherwise sound a repair is the right answer. We do them.
A crazed dome, a rusted steel frame, a rotted curb or a unit over about twenty five years old with a failed seal are replacements. Sealing over any of those buys a season and the money is gone. A replacement on a sound existing curb starts at $2,079 installed and cutting a new opening where there was never one starts at $3,500 installed, both published on the pricing page with the unit prices beside them.
One thing worth checking before anybody prices anything: if the unit sits over a stair and it has a hood or a vent on it, it may be a required smoke vent rather than a plain skylight, which changes both what can go back and whether the job has to be filed. The permits and landmarks page covers it.
Send us your photos or call (718) 646-7053. Estimates are free and we will tell you if it is condensation.
That pattern points at the flashing rather than the unit. In ordinary rain water runs down the glass and off the flashing the way it should. Driven rain pushes up under the laps and finds any place the flashing was cut short, reused from the last roof, or sealed with caulk instead of lapped metal. It is the most repairable of the real leaks.
That is condensation and it is not a leak. Warm humid indoor air meets the coldest surface in the room. Run the bathroom or kitchen fan, keep the room moving air, and watch whether it clears by midday. If the haze is between the two panes rather than on the inside face, that is a failed seal in the glass unit instead, which is also not water coming in from outside.
Often it still is, but not at the glass. Water gets in at the flashing or through a failed curb, runs along the top of the ceiling or down a rafter and drops where it finds a seam. The further the stain is from the opening, the more likely the curb is involved rather than the unit. It can also be the roof itself with the skylight taking the blame, which is why the photo from back far enough matters.
That is the normal history on these. Caulk is not a flashing and it fails in a season or two, and once a few rounds of it are on there it hides what is underneath. Nine times out of ten the metal under it was never right. The fix is to pull it apart and flash it properly, not to put another bead on.
That is a crazed acrylic dome and it is at the end of its life. The hairline cracks keep going and the plastic has lost its flexibility, so sealing it does not hold. We cover what replaces one, and what a glass unit changes about the room, on the acrylic dome page.
Usually not worth it. Those frames rust from the inside out and the putty that bedded the glass is long past. Wire glass was also the old safety standard and a current sloped glazing build wants laminated glass in the inboard pane. We go into the replacement options on the wire glass and steel skylight page.
Yes, and it usually means water is standing above the unit rather than running past it. Ice dams above a skylight on a pitched roof, and ponding or a slow drain on a flat one, both put standing water against the flashing for days, which no flashing is designed for. Fixing the skylight alone will not solve it, so this one needs the roof looked at with it.
We can usually tell you what it probably is and roughly what it takes from good photos, which is enough to decide whether it is worth going further. Nobody prices a curb from the floor, so the final number comes after somebody is on the roof with a tape. The estimate visit is free, and if it turns out to be condensation we will say so and there is no job.
Call us. Call rather than email if water is moving, because the first thing to sort out is whether it needs covering today or whether it can wait for a proper look. More on repair work on the skylight repair page and the leak repair page.