Short Answer
Sometimes. The appropriate solution depends on whether the failure involves glazing, frame, flashing, sealants, or surrounding roofing.
Detailed Explanation
Skylight repair depends on what's failing. If the problem is deteriorated sealant around the frame, resealing may solve it. If the flashing has failed but the skylight is sound, reflashing can fix the leak. If the glazing (glass) is cracked or the insulated seal between panes has failed (fogging), the glass or sash may need replacement. If the frame itself is damaged or deteriorated, the skylight may need full replacement. The key is proper diagnosis: determining which component has failed and whether it can be repaired or needs replacement. A skylight that's been leaking for years may have damage to the surrounding roof deck as well, which should be evaluated and repaired.
Why It Matters
Accurate diagnosis of what's failing determines whether repair is possible or replacement is needed. Misdiagnosis leads to repeated unsuccessful repairs.
When Repair Makes Sense
The failure is limited to sealant, flashing, or glazing that can be replaced without removing the skylight.
When Replacement Makes Sense
The skylight frame is damaged, the skylight is old and deteriorated, or repeated repairs haven't solved the problem.