Skylights and Sun Tunnels on Columbia Homes: Repair, Replace, or Leave Alone

Columbia’s original architects liked daylight. Contemporary and split-level designs across the villages were built with skylights as a standard feature rather than an upgrade, often several per house.

Which means a great many Columbia homes are carrying skylights that are decades old, sitting in a roof that has been replaced once or twice around them. That combination is where the leaks come from.

Most Skylight Leaks Are Not the Skylight

This is the single most useful thing to know. When water appears near a skylight, the glass unit itself is rarely the culprit. The failure is almost always one of:

  • Head flashing at the top of the unit, where water is deflected around it
  • Step flashing along the sides
  • The saddle or cricket above the unit on a wider skylight
  • The seal between the frame and the curb it sits on
  • Condensation, which is not a leak at all

That last one matters. Water running down the inside of the glass on a cold morning, worst in winter, drying up in summer, is condensation caused by a ventilation or humidity problem. Replacing the skylight will not fix it.

The Replacement-Timing Mistake

Here is what happens repeatedly in Columbia. A homeowner replaces the roof. The skylights are twenty-five years old but not leaking, so they are left in place and flashed into the new roof.

Three years later a skylight fails. Replacing it now means cutting into a nearly new roof, reworking the flashing, and hoping the shingle color still matches.

If a skylight is past about two-thirds of its expected life when the roof is being replaced, replacing it at the same time is substantially cheaper than doing it separately later. The labor overlaps almost entirely. Ask for it as a priced option on the roofing estimate and decide with the number in front of you.

Repair or Replace

Usually Repairable

  • Flashing failure with a sound glass unit
  • Deteriorated exterior seals
  • Cracked or missing flashing at the head

Usually Replace

  • Fogging between the panes, which means the seal has failed
  • A visibly warped or rotted frame or curb
  • Plastic domed units from the original build, which become brittle and craze
  • Any unit where the roof around it is being replaced anyway and the unit is old

HF Roofing Contractor handles skylight repair and replacement, including replacing older units as part of a roofing project.

Sun Tunnels Where a Skylight Will Not Fit

A sun tunnel runs a reflective tube from a small roof dome down into a room below. It brings daylight into interior spaces — hallways, bathrooms, stairwells, the middle of a floor plan — that could never take a conventional skylight.

They are a smaller roof penetration, which means less to go wrong, and they suit Columbia’s interior-heavy floor plans well. They do not give you a view or ventilation, so they complement skylights rather than replacing them.

The Attic Side Nobody Checks

A skylight shaft runs from the roof deck down through the attic to the ceiling. That shaft needs insulation and an air seal, and on older Columbia homes it frequently has neither.

An uninsulated shaft produces condensation that looks exactly like a roof leak, along with a cold spot in the room and heat loss in winter. Anyone diagnosing a skylight problem should be looking at the shaft from inside the attic, not only at the roof.

Ventilation generally changes when an old roof is replaced — a point covered in the cedar shake replacement guide — and skylight shafts are part of that picture.

Frequently Asked Questions

That points at head or step flashing rather than the unit. Wind pushes water up under coverings that shed vertical rain perfectly well.

 

Condensation appears on the inside of the glass, is worst in cold weather, and stops in summer. A leak follows rain regardless of season and usually stains the surrounding ceiling.

 

If they are old, almost always. Doing it later means cutting into a new roof for a fraction of the saving.

 

Most places, provided there is a reasonably clear run through the attic. Framing and ductwork can force the position to shift.

Getting Skylights Assessed

HF Roofing Contractor works throughout Columbia and Howard County on skylights, sun tunnels and the roofs around them. If a replacement is coming up, the village approval process is the step to start early, and homes with shallow roof sections should also read low-slope roofs on Columbia townhomes. Debris collecting above a skylight is a common cause of flashing failure — see tree canopy, gutters and Columbia roofs.