Skylight Installation and Repair in Greater Boston

Most skylight calls start the same way. A stain shows up on the ceiling after a hard rain, or after snow melts off a cold roof. The glass is often fine. The opening around it is not.

KMK Roofing installs new skylights and repairs the ones that already leak, for homes across Greater Boston and the North Shore.

When the leak is the flashing, not the glass

The metal skirt around a skylight is what ties the frame to the shingles. If a corner lifts, a seal dries out, or the shingles no longer lap over that metal the right way, water gets in. Freeze and thaw makes that seam worse. So does a winter of ice sitting on the bottom edge of the unit.

If the pane is intact and the stain sits near the skylight, start with a look at the opening. That is often a roof repair, not a new skylight.

Sometimes the stain is near the skylight and the water entered somewhere else, then ran along the wood. A pipe boot or a chimney can do that. If the metal around the glass still looks tight, the next check is the vent flashing, not another tube of sealant on the glass.

Repair, or a new unit

A sound frame with failed flashing can often be resealed and reflashed. That is a repair.

Replacement makes more sense when the frame is cracked, the sash will not close, the glass is fogged between the panes, or the wood around the opening has gone soft. A leak that has been dripping for a season can do that. Covering it with caulk does not dry the deck.

On a repair or a new install, the shingles around the opening come up so the wood can be seen. New flashing goes on so water sheds down the roof, instead of sitting against the curb. A bead of caulk on the outside may slow a drip for a few months. It is not the same job.

If the rest of the roof is worn out, it is usually better to handle the skylight during a roof replacement. Flashing a new unit into shingles that are already failing just moves the leak.

What a New England roof asks of a skylight

Snow sits on a low-slope skylight longer than it sits on the rest of the roof. Ice can build at the bottom edge, the same way it builds at the eaves. The opening needs a clear path for that meltwater, and a waterproof layer around the curb so a backup does not reach the ceiling.

What sits above the unit matters too. A valley dumping onto the glass, or a tree dropping wet leaves against the frame, will keep causing trouble no matter how careful the flashing is.

Curb-mounted and deck-mounted skylights go in differently. The right one depends on the pitch of your roof and the unit that is already there. We will say which one we are looking at before any wood comes off.

If water is coming in now, contact KMK Roofing and we will look at the opening before the next storm widens it.