Skylight contractors glossary
Short, plain-English definitions of the terms you'll meet when choosing a skylight contractor provider in Citrus County, Florida.
- Condensation on skylights
- Condensation on skylights is water droplets or fog that form on the glazing or frame when moist indoor air cools to its dew point against the cold surface. Unlike a leak, it comes from humidity and temperature rather than water entering the roof assembly.
- Curb-mounted skylight
- A curb-mounted skylight is a unit set on a raised frame, or curb, that stands above the roof deck and is flashed into the roof around it. Deck-mounted units sit flush against the roof surface with no raised base.
- Deck-mounted skylight
- A deck-mounted skylight is a low-profile skylight fastened directly to the roof deck without a separate curb. It sits flush with the roofline and is typically used where a shallow, streamlined profile is preferred.
- Design pressure rating
- A design pressure rating is the positive and negative wind load, measured in pounds per square foot (psf), that a skylight is tested to withstand without failing. It tells you how much pressure the unit can take from wind pushing on it or pulling away from it.
- Fixed skylight
- A fixed skylight is a roof-mounted window unit that is sealed shut and admits natural light only, with no ability to open for airflow. It is the simplest and most common skylight type for rooms that need daylight but not ventilation.
- Glazing seal failure
- Glazing seal failure is the breakdown of the sealed edge of an insulated glass unit, letting moisture and air into the space between the panes. The most visible sign is fogging or condensation trapped between the glass layers.
- Laminated glass
- Laminated glass is glass made of two or more layers bonded to a plastic interlayer, usually polyvinyl butyral (PVB). When the pane is struck or cracked, the interlayer holds the fragments together, which resists penetration and reduces the risk of falling glass.
- Low-E coating
- A Low-E (low-emissivity) coating is a microscopically thin, mostly metallic layer applied to glass that reflects infrared heat and filters UV light while still letting visible light through. In skylights, it helps limit heat gain and fading indoors.
- Polycarbonate glazing
- Polycarbonate glazing is a clear or tinted thermoplastic sheet used in place of glass in skylights and roof panels, valued for its high impact resistance. It is much tougher than acrylic and glass, which makes it a common choice where hail, debris, or heavy storms are a concern.
- Roof sealant and flashing tape
- Roof sealant and flashing tape is a self-adhered waterproofing membrane applied around the edges of a skylight frame where it meets the roof deck. It bridges the seam between the curb or frame and the roofing material so that rain and wind-driven water cannot get underneath.
- Skylight flashing
- Skylight flashing is the metal or membrane material that seals the joint between a skylight curb and the surrounding roof so water runs off instead of getting in. It is typically made up of a sill, step, and head piece.
- Solar heat gain coefficient (SHGC)
- Solar heat gain coefficient (SHGC) is a number from 0 to 1 that measures the fraction of incoming solar heat that passes through a window or skylight, both directly and as heat absorbed and re-emitted indoors. Lower values admit less heat, which matters in hot, sunny climates like Florida.
- Tubular skylight
- A tubular skylight, also called a sun tunnel, is a small daylighting system made of a rooftop dome, a reflective tube running through the attic, and a ceiling diffuser. It carries natural light into rooms that have no room for a conventional skylight.
- What is a light shaft?
- A light shaft is the framed passage that connects a roof opening to the ceiling opening below it, letting daylight travel through the attic or roof space. It may run straight down or be splayed (angled wider at one end) to spread light into the room.
- What is a Miami-Dade NOA?
- A Miami-Dade NOA (Notice of Acceptance) is the official approval document issued by Miami-Dade County's product control division for a building product that has passed impact and wind-pressure testing for the High-Velocity Hurricane Zone. It confirms the product meets the county's stricter building code for storm-prone areas.
- What is a skylight curb?
- A skylight curb is the raised frame, usually wood or a prefabricated material, built into the roof deck to hold a skylight above the roofing surface. It gives the unit a level base and a height that the flashing can seal against.
- What is a solar-powered skylight?
- A solar-powered skylight is a roof window with a small built-in solar panel that generates the electricity needed to open and close the unit and operate its shades or blinds. It needs no hardwired power connection to work.
- What is an acrylic dome skylight?
- An acrylic dome skylight is a domed, plastic bubble unit, either single or double walled, that is installed in a flat or low-slope roof to bring daylight into the space below. Acrylic is a lightweight, impact-resistant plastic that is commonly used for this type of skylight.
- What is an NFRC label?
- An NFRC label is a standardized rating sticker on a window or skylight, issued under the National Fenestration Rating Council's testing program, that lists independently verified energy performance values. It lets buyers compare products on the same basis.
- What is Florida product approval?
- Florida product approval is the state system through which building products, including skylights, are reviewed and approved for use under the Florida Building Code. An approved product carries a state approval number showing it meets the code's performance requirements.
- What is tempered glass?
- Tempered glass is safety glass that has been heat-treated to increase its strength, and it breaks into small, relatively harmless pieces instead of sharp shards. It is commonly required for skylights and overhead glazing where broken glass could fall on people or property.
- What is U-factor?
- U-factor is a rating of how easily heat passes through a skylight assembly, including the glazing, frame, and curb. Lower U-factor numbers mean better insulation.
- Wind-borne debris region
- A wind-borne debris region is a mapped coastal zone in the Florida Building Code and ASCE 7 where openings such as windows, doors, and skylights must resist flying debris through impact-rated glazing or approved shutters. In Citrus County, the rules affect skylight replacements and new installs on the coast and barrier areas.