Skylight Repair and Installation in Trenton: Stop the Drip at the Curb

Why do skylights leak more than the rest of the roof?

A skylight interrupts the roof and relies on flashing and sealant to rejoin the roof's waterproofing. Those parts move with temperature and age faster than shingles. Sealant dries and cracks, flashing loosens, and wind-driven rain or melting snow finds the smallest gap around the frame.

Snow can lie against the uphill side of the frame and melt slowly into it, which tests the head flashing. Rain driven sideways tests the sides.

The trouble can be hard to diagnose from inside, because the water runs along the frame before dripping. A roofer works from the stain back up.

Is it condensation or a leak?

Condensation forms on cold glass or frames when warm moist air meets them, usually on cold mornings, and the water is on the glass or frame surface. A leak appears after rain or thaw and stains the shaft. A roofer can tell the difference and advise on ventilation or glazing if it is condensation.

A bathroom or kitchen under a skylight adds moisture, and a poorly ventilated room is more likely to fog the glass.

If water appears between the panes, the glazing seal has failed and the unit needs replacing.

Can an old skylight be reflashed without replacing it?

Often yes, if the frame and glazing are sound. The roofer lifts the surrounding shingles, replaces the old flashing with new metal laid in layers and relays the roof around it. If the unit itself is leaking or rotted, replacement with a matching flashing kit is the better route.

Sealant alone, spread on the outside, rarely lasts. A proper reflash costs more at the start and avoids repeated callbacks.

Ask the roofer to explain which parts they will replace and what they will reuse.

What goes into putting in a new skylight?

A new skylight cuts through the roof framing and ceiling, so it involves structure, flashing and interior finishing. It may need a permit. Placement matters, as sun and heat gain affect the room. Ask the roofer to explain the plan and the flashing method before you agree.

Check with the municipal construction office about permits, and with any homeowners association about rules.

A new opening on a historic house may need review for visible changes. Ask first.

What about skylight leaks that come back after a repair?

A repeat leak usually means the first fix treated sealant while the real cause was flashing, a cracked frame, a failed glazing seal or condensation. The roofer should recheck the whole assembly, ask when and in what weather the water appears and explain why the new repair differs from the last one.

Skylight leaks are famously stubborn because several faults can look identical from below. Water running down the shaft might be rain entering at the head flashing, meltwater getting under the sill, vapor condensing on the glass or a hidden crack in the frame. Fixing the wrong one leaves the stain coming back.

A useful habit is to keep notes: the date, the weather and where the water appeared. A leak that shows only in wind-driven rain points to a side or head joint. One that shows only on cold mornings points to condensation. One that shows during a thaw points to snow lying against the frame.

If the unit is old and has been resealed more than once, the cost of repeated repairs may exceed a proper reflash or a replacement. Ask the roofer to compare the options in writing.