Is the Skylight Leaking—or the Roof Around It?

Water can enter through the skylight unit, at the junction between the unit and roof, or through nearby roofing. Indoor condensation is another possibility. Moisture around the trim alone does not distinguish these sources, so the pattern and surrounding materials need to be considered together.

The US Department of Energy’s skylight assessment guidance considers the unit, roof covering and flashing. VELUX also explains how indoor moisture can cause condensation. These are explanations for a provider conversation, not instructions for roof access.

Is water on the room side of the glass, at a frame corner, around the trim or farther out on the ceiling? Keep those locations separate in your notes. A photograph from the floor can preserve a detail that may dry before an assessment.

Record whether the symptom appears during rain, after rain or at another time. Include recent work around the opening. A clear history helps the provider consider the skylight and roof surround without assuming a cause.

The skylight unit

The glazing, frame and operation of the unit are one part of the assessment. A model name or installation record can be useful if available.

The roof opening

The junction between the skylight and roof includes water-management details. Ask whether the surrounding roofing and flashing will be considered.

The indoor environment

If droplets appear when it has not rained, say so. A provider may need to consider moisture conditions rather than treat every symptom as outside water entry.

A recommendation to replace a unit, work on flashing or repair nearby roofing should explain which finding supports it. Ask what is included and whether another trade or specialist is needed for any part.

General manufacturer guidance describes flashing as an important roof-opening detail. It does not establish the cause at your home. Use our flashing service guide and skylight leak page to frame the conversation.

If earlier sealant or a patch was used, keep the date, photographs and written scope. Ask whether the new assessment revisits the original source and checks the adjacent details. A second application should not be treated as an explanation on its own.

The guide to a leak that returns after patching offers a follow-up checklist. If a provider has already completed work, start by contacting that provider and explaining the recurrence.

• Location of the moisture relative to the glass and frame.
• Whether the symptom follows rain or appears in dry weather.
• Approximate unit age or model, if known.
• Any recent roof or skylight work.
• Safe indoor photographs.
• The actual Cupertino address and who can authorize access.

You do not need all of these details to make a first enquiry. Share what you know and make clear where you are uncertain.

Do not climb onto a roof to photograph flashing or test a skylight. Ask the provider how it will assess the concern safely and what access it needs. Availability, weather and the type of work can affect arrangements.

Cupertino RoofLeak is a referral service. Independent providers determine the assessment, price and schedule, and the homeowner decides whether to hire.