Glossary of Skylight Terms A – D

Acrylic Dome

A method of skylight glazing that has a dome-like shape and is made of acrylic, known for its strength and durability.

Known as Acrylic Skylights

Air Leakage

This is the measure of air leakage, typically expressed in cubic feet per minute per square foot. The higher this value, the more significant the heat loss and reduced airtightness of the window structure.

Annealed Glass

A type of glass that is not subjected to thermal treatment and essentially has no internal stresses. This type of glass is often referred to as “float glass” due to the manufacturing process, in which molten glass is evenly distributed on the surface of molten metal.

Annealed Glass is durable and long-lasting but is less resistant to impacts and temperature changes compared to tempered glass, which undergoes additional heat treatment.

Argon gas

This inert gas, constituting about 0.93% of the Earth’s atmosphere by volume, was discovered in 1894 by British scientists Lord Rayleigh and William Ramsay. It is colorless, odorless, and tasteless, non-toxic, and does not support combustion. One of its key characteristics is extremely low chemical reactivity, making Argon widely used in various fields of science and technology. For example, it is used to enhance thermal insulation properties in window glazing units.

Argon is used in skylights and VELUX roof windows.

Bent Glass

Glass that has been bent by heating it above its softening point. The bending occurs due to gravity or with the help of molds that shape the glass. This method allows for the creation of smooth curves and bends often used in architecture and design.

Also known as: curved glass.

Blinds

Blinds are a versatile interior element that allows effective regulation of the amount of light entering a room. They help save on energy resources by reducing the need for air conditioning in the heat and contributing to heat retention in the winter.

Cladding

The exterior finish applied to the frame or structure of a building to protect it from environmental impacts. This layer not only serves a protective function but also enhances the appearance of the building, creating aesthetic harmony.

Also known as: exterior cladding, wooden cladding, aluminum cladding, granite cladding, skylight cladding.

Combi-flashing

This allows for the installation of multiple skylights in combination, providing virtually unlimited possibilities for creating original design solutions.

Condensation

This is the physical process where water vapor turns into water droplets when warm, humid air comes into contact with a cold surface. This process is often observed on windows during cold weather, when the glass becomes covered with water droplets.

VELUX windows use special technologies, such as low-emissivity coatings, which protect the inner surface of the glass from the effects of cold outdoor air, as well as inert argon gas sealed between two layers of glass. These measures help maintain optimal conditions inside the room and prevent condensation from forming.

Condensation Gutter

Designed to collect and channel moisture that forms on windows due to temperature fluctuations, this mechanism prevents excess water from accumulating on the glass and frame. It directs the moisture outside through special drainage holes or allows it to evaporate naturally.

Also known as: condensation channels

Controls

A system for managing the opening, closing, and adjusting of ventilation hatches or blinds. The controls can be operated manually or via an electric drive, which is powered by a motorized mechanism and controlled through a remote.

Also known as: Remote Controls

Cross Rafter

Used in frame structures, it is positioned horizontally or at a slight angle between the rafters and helps distribute the load, increasing the overall stability of the structure. Cross rafters are often employed in skylight systems, where they support the roofing material and help maintain its shape.

Also known as: purlin

Curb

This structural element is designed for the installation of a skylight. It serves as a barrier and seal around the skylight, ensuring a tight fit and protection from external elements, including water, dirt, or potential mechanical damage. The curb can be either a wooden frame constructed on-site or a pre-made metal structure.

Curb mounted

The design of the skylight is such that it can be securely installed and fixed onto a wooden curb, becoming an integral part of the roof structure. This mounting method is particularly suitable for low-pitched roofs. Skylights cover the curb from above, like the lid of a box, ensuring a tight and stable fit to the roof.

Custom Skylights

Specially designed structures tailored to unique architectural features and intended for use in unusual spaces and conditions.

Deck-Mounted Skylight

A skylight mounted directly onto the roof, fitting closely with the roofing material. This type of installation provides reliable leak protection and helps maintain the roof’s aesthetic appeal without disrupting its overall design.

Diffused Light

This is soft, indirect light that is evenly distributed throughout the space, creating a pleasant atmosphere. It passes through filters, such as frosted glass or special light-diffusing materials. This process softens shadows and eliminates glare, making the lighting more natural and comfortable for the eyes.

The diffusing properties of glazing materials are often evaluated using the “haze factor,” which characterizes their ability to scatter light.

Double Glazed

A structure consisting of two layers of glass with an air space between them. This improves insulation against cold and noise, minimizing heat loss and reducing external sound intrusion.

Also known as: double glazed window, double glazed glass, double glazing panels