Skylight installation is roofing work, not glazing work. The unit itself is the easy part — what determines whether a skylight leaks in year eight is the curb it sits on and the flashing that ties it into the roof. We install new skylights and replace failed ones on tile, shingle and low-slope roofs across South Florida, and we treat the flashing as the product.
New installations: cutting into a roof properly
A new opening means framing. The rough opening is cut, headers are added between rafters or trusses so the structure is not compromised, and a curb is built and set plumb and level before any roofing material is touched. Cutting a truss without engineered detailing is not something we do, so the layout is planned around the existing framing where possible.
We prefer curb-mounted units on most South Florida roofs. A raised curb keeps the glazing well above the water plane, which matters on low-slope decks and on tile roofs where water can back up behind an obstruction during wind-driven rain. Deck-mounted units are appropriate on steeper shingle slopes where the profile matters.
Replacing a failed or leaking skylight
Most 'leaking skylights' are not leaking through the unit at all. They are leaking at the flashing, at a failed sealant bead someone applied instead of flashing, or at a cracked acrylic dome that has spent twenty years in the Florida sun. Older bubble domes yellow, craze and eventually split; the seals on double-glazed units fail and fog between panes.
Condensation is the other common misdiagnosis. Water running down the inside of a shaft in an air-conditioned house during humid weather is often condensation on a poorly insulated shaft, not roof water. We check which one it is before quoting a replacement, because they have different fixes.
The flashing detail is the whole job
A properly flashed curb has four parts working in the right sequence: a base or apron flashing at the downslope side, step flashing woven course by course up both sides, counter-flashing lapping over the vertical leg on the curb, and a head flashing with a cricket or saddle on the upslope side to divert water around the unit rather than into it.
On tile roofs that detail is bigger and more three-dimensional — pan flashing has to run under the tile field with enough width to carry water past the curb, and the tile has to be cut cleanly around it. On low-slope membrane roofs the base flashing runs up the curb to a proper height and is terminated under counter-flashing, never at a bead of sealant. Sealant is a supplement to a flashing detail, never a substitute for one.
Glazing, impact requirements and permits
South Florida skylights sit inside the same wind-borne debris rules as the rest of the building envelope. Units for this region are specified with impact-rated glazing and an approval covering the assembly, and in Miami-Dade and Broward that means a current Notice of Acceptance for the unit and its installation method.
Skylight work is permitted work, and cutting a new opening involves the structural side of the code as well as the roofing side. We handle the permit and the inspection. Replacing like-for-like is a simpler process than creating a new opening, but both go through the municipality.
Doing it during other roof work
The cheapest time to install or replace a skylight is while the roof around it is already open. If a shingle re-roof or a tile re-roof is planned, the flashing gets rebuilt as part of the new system rather than tied into a finished roof afterwards.
Replacing a twenty-year-old unit at re-roof time is nearly always the right call. Reusing an aged skylight under a new roof means the one component guaranteed to fail first is the one you did not replace. If a skylight on a low-slope area is the current problem, that is flat roof repair work on the curb detail.