Roof Repair
Adding a Skylight to a Tile Roof Without Creating a Leak
Tile roofs dominate North County, and cutting a new skylight into one is where amateurs create leaks that last for years. Here's how it's done right.
Can you add a skylight to an existing tile roof?
Yes, but it's specialized work. A skylight in a tile roof needs a proper curb, a purpose-built tile flashing kit that laps under the upper courses, and careful re-cutting of the surrounding tile. Done by a tile-experienced crew it lasts decades; done as if it were a shingle roof, it leaks within a year.
Tile changes everything about the install
We install and repair a lot of roof types, but tile is our specialty, and skylights are where tile experience really shows. Most skylight leaks we're called to fix on tile roofs were installed by someone who treated the tile like it was asphalt shingle. It isn't. Tile sits proud of the deck on a drainage plane, water runs under the tile as well as over it, and the flashing has to manage both.
That means you can't just cut a hole, drop in a curb, and lap a flat flashing over the top. The upper tile courses have to be lifted and the skylight's head flashing tucked underneath them so water sheds onto the tile below the unit, never behind it. Get that relationship wrong and the roof will funnel water straight into the light well.
Deck mount versus curb mount on tile
On a tile roof we almost always specify a curb-mounted skylight or a deck-mounted unit paired with a proper tile flashing kit that raises the unit above the tile plane. The reason is height. Tile is thick, and if the skylight sits too low relative to the tile surface, the courses above it dam water against the head of the unit. A raised curb keeps the glass and its seals above the flow.
Manufacturers make tile-specific flashing kits with a tall, sculpted step and head piece designed to weave into S-tile or flat-profile tile. We use these rather than fabricating flat flashing, because the factory kit is engineered for exactly the profile of your tile and the runoff volume it carries.
The cut is the moment of truth
Framing the opening is precise work. We locate the rafters, plan the opening to avoid cutting more structure than necessary, and add headers to carry the load around the new hole. On the roof surface, the tile has to be removed intact where possible so it can be reused, and the cuts through underlayment and deck have to leave clean edges for the new flashing to seal against.
This is also when we build the light well, the shaft that channels daylight from the roof down to the ceiling opening. In a home with an attic, the well is framed and drywalled at an angle to spread the light. We flash and waterproof the roof opening completely before that interior work begins, so there's never a question of the well itself getting wet.
Sequencing the flashing and resetting the tile
The order of operations is what keeps the skylight dry for decades. We install the curb, then the underlayment turns up the curb and is sealed. The apron flashing goes at the bottom first, then the step flashing up the sides, then the head flashing at the top, each lapping over the piece below it exactly as water flows.
Only then do we reset the tile. The lower courses tuck over the apron, the side tiles are cut to sit against the step flashing with the proper gap, and the upper courses lay over the head flashing. Where the profile needs it, we use closures and mortar to seal the gaps without blocking the drainage path underneath.
| Element | Tile roof requirement | Why it matters |
|---|---|---|
| Mount type | Raised curb or tile deck kit | Keeps glass above thick tile plane |
| Flashing kit | Tile-profile specific | Fits S-tile or flat profile drainage |
| Head flashing | Tucked under upper courses | Sheds water onto tile, not behind it |
| Tile handling | Remove intact, re-cut, reset | Preserves matching and drainage |
| Closures | At profile gaps, drainage kept open | Blocks entry without damming water |
Why this is worth doing right the first time
A skylight cut into tile by an inexperienced crew creates a leak that's expensive to chase, because the water travels under the tile before it appears indoors and the whole area has to be opened up to diagnose it. A leak like that can rot the light well framing and stain fresh drywall before anyone connects it to the skylight.
When it's done by a crew that lives and breathes tile, the new skylight becomes a seamless part of the roof's drainage system. We warranty our workmanship because we've done enough of these across North County to know exactly where the water wants to go and how to send it somewhere else.
A San Marcos great room that needed light without a leak
A family in San Marcos wanted to brighten a north-facing great room under a concrete S-tile roof. They'd gotten a bid from a general contractor who planned to cut the hole and use standard flat flashing. They called us for a second opinion after a neighbor's similar job started leaking.
We planned the opening between two rafters, added headers, and specified a curb-mounted unit with the manufacturer's S-tile flashing kit rather than fabricated flat metal. We removed the surrounding tile intact, cut the deck cleanly, ran the underlayment up the curb, and layered the apron, step, and head flashing in sequence before resetting the tile with proper closures.
The room got the daylight they wanted, and two rainy seasons later there's not a mark on the new drywall. The difference wasn't the skylight brand, it was flashing the tile the way tile has to be flashed.
Key takeaways
- Tile roofs need a raised curb or tile-specific deck kit, not flat flashing.
- Head flashing must tuck under the upper tile courses so water sheds ahead of the unit.
- Tile should be removed intact, the deck cut cleanly, and tile reset with closures.
- Water runs under tile as well as over it, so both paths must be managed.
- An inexperienced tile cut creates hidden leaks that rot the light well before you notice.
Frequently asked
Is it harder to add a skylight to tile than to a shingle roof?
Will my existing tile match after a skylight is added?
Do I need a tile-specific skylight flashing kit?
Can you add a skylight without disturbing the whole roof?
Have a roof question we didn't cover?
Ask us during a free inspection. Straight answers, no pressure.