Skylight — definition, uses, identification, and replacement

A skylight is a glazed roof opening that brings daylight into the interior of a building from above.

Skylight diagram — labeled parts, dimensions, and installation context

What It Is

Skylights can brighten dark rooms, hallways, and vaulted spaces that do not get much wall-window area. Because they penetrate the roof, they depend on careful flashing, glazing seals, and roof integration to stay weather-tight.

A skylight can be fixed or operable and may include shades or venting controls.

Types

Common types include fixed skylights, venting skylights, curb-mounted units, deck-mounted units, tubular daylight devices, and roof windows.

Where It Is Used

They are used in roofs over bathrooms, hallways, stairwells, kitchens, and upper-story rooms where added daylight or ventilation is desired.

How to Identify One

Look for a glazed unit set into the roof with an interior light shaft or direct opening to the room below.

Replacement

Replacement is needed when the glazing seal fails, the frame leaks, the flashing is wrong, or the unit is outdated and inefficient.

Skylight — FAQ

What does a skylight do?

A skylight is a glazed roof opening that brings daylight into the interior of a building from above. They are used in roofs over bathrooms, hallways, stairwells, kitchens, and upper-story rooms where added daylight or ventilation is desired. In practical terms, it matters because skylights can brighten dark rooms, hallways, and vaulted spaces that do not get much wall-window area. Because they penetrate the roof, they depend on careful flashing, glazing seals, and roof integration to stay weather-tight.

How can I tell if the skylight needs attention?

Condensation between panes, ceiling stains, drafts, or visible flashing deterioration are the main warning signs. Look for a glazed unit set into the roof with an interior light shaft or direct opening to the room below.

Can a homeowner handle skylight work, or should I call a pro?

Cleaning and shade maintenance are homeowner-friendly. Full skylight replacement crosses into roofing and flashing work. If the issue involves hidden leaks, structural support, code compliance, or specialty tools, professional help is usually the better path.

What should I match when buying a replacement skylight?

Match the roof pitch, rough opening, glazing type, venting needs, flashing kit, and shaft configuration. Taking the old part, measurements, or a manufacturer model number with you usually saves time and return trips.