De-mystifying rooflight terminology
Updated: Nov 19, 2019
There are many different ways to describe skylights and the components used in installing and operating them. Not only this but the term skylight is also referred to as many different things such as rooflight, roof window, sky light or occasionally people refer to them as Velux, who are of course are a manufacturer of skylights.
Actuators - are the mechanisms used to electronically open and close the skylights. At Stella Rooflight we use a range of electronic actuation subject to the requirements of the opening casement. If you require your roof window to have some or all of the casements opening then our team will explain what is achievable when you make your enquiry.
Baseplate - this is the part of the rooflight that contains the hinges for the casement to be bolted onto. The fixing lugs are located on the underside of baseplate along with the wooden interior liner. This piece of the skylight sits between the structural support timbers (rafters).
Bespoke Skylights - this term is used to describe a rooflight which is custom made to your specification. This can be a change to a conservation rooflight, a more contemporary roof window or a range of roof windows for a flat roof application. When making your enquiry for a Stella Rooflight you have the ability to change a whole range of options including glazing specification, colour, change the wood that your liner is made from, add or remove glazing bars and have opening or fixed casements.
Casement - this is the opening piece of the rooflight which contains the self-clean glass units. This section is fixed onto the baseplate hinges. The casement is viewable once fitted in the roof.
Coastal Location - we produce the rooflights to a very high standard that are suitable for use in coastal locations as standard. If you have any questions about the location of your property or the likely implications of high salinity or pollution content in the atmosphere, please talk to our team.
Condensation - condensation is the water that results from the conversion of water vapour in the atmosphere. The air in our homes always contains water vapour which is usually invisible. The warmer the air, the more water vapour it can hold but there is a limit to the amount it can hold for a given temperature. Should you require additional information, please ask our team for a copy of the Glass & Glazing Federation fact sheet.
Conservation Rooflight - during the 18th century rooflights, in their most primitive form, were used to bring light into agricultural buildings. It therefore seems uncanny that todays rooflights are yet again providing an architectural design solution to the increasing trend of converting old or disused industrial buildings into domestic dwellings or business premises.
Conservation rooflights are easily recognised by their low profile which means they sit flush and remain unobtrusive to the buildings original architecture. Another characteristic is their slender appearance as conservation requirements stipulate that a minimal amount of framework should be visible. This design feature becomes even more significant when rooflights are placed next to each other.
Contemporary Skylights - a stylish and streamlined roof window for customers who are seeking a more modern look for their roof glazing. The design remains low profile and unobtrusive whilst offering a high specification of energy efficient, self-clean glazing. These typically do not have glazing bars in the same way that conservation rooflights do.
Escape Rooflights - although some rooflights are hinged on the side, our escape version are top hung to reduce any possible issues with light rain and to retain a matching appearance when installed alongside our standard range. Stella access or escape skylights and are fitted with gas struts so the skylight casement stays open. Supplied with a brass winding mechanism for daily use, the gas springs should only be deployed when the casement is required to stay open. Further details can be obtained when speaking to our team.
Gas Struts - are pressurised cylinders that are attached to the rooflights so that they can remain open unaided in a similar way to the boot of your car.
Hand Winder - is the mechanism used to open and close the rooflights when the rooflights are within reach. These typically have a handle or a wheel on the end to aid operation.
Pole Winder - is the mechanism used to open and close the rooflights when the rooflights are out of reach. This type of rooflight mechanism would usually be operated by a separate crank pole.
Head Detail - is the top section of the rooflight.
Jamb Detail - are the side sections of the rooflight.
Cill – this is the bottom section of the Rooflight.
Linking bars - are the bars used to link skylights together so that they are in continuous runs. Occasionally specifiers refer to these as Studio-Linked but we call them Stella Link Light.
Listed building - a building or other structure officially designated as being of a special architectural, historical or cultural significance. If your property is Listed you will need to work closely with your local authority before making changes to the building fabric. An excellent resource for Listed property owners.
Overall Sizing - the maximum width and length of the baseplate, much of which is covered by the tiles or slates.
Pitched Roof - is a roof structure where the roof is set at a slant. Our Stella conservation skylights can be used between 17 and 70 degrees in slate and tile or 30 and 60 degrees in a pantile roof.
Roof Window - is an architectural term for the frameset with glass which is fitted to an opening in the roof to admit daylight.
Rooflight - is another way of describing the frameset with glass in that is fitted to an opening in the roof to admit daylight.
Skylight - is another word to describe the frameset with glass in that's fitted to an opening in the roof to admit daylight.
Self-Cleaning Glass - an important technological breakthrough was introduced to the UK in 2002, in the form of the worlds first self-cleaning glass. Considered by many to be an impossible dream, self-cleaning glass makes maintaining rooflights significantly easier. Saint Gobain BioClean is effectively the same as conventional glass, but with a specially developed coating on the outside, that once exposed to daylight, reacts in two ways. Firstly, it breaks down any organic dirt deposits through a photocatalytic process, and secondly, when it rains, instead of forming droplets, the water spreads evenly over the surface and takes the dirt off with it. It is kinder to the environment than ordinary glass and it is the ideal choice for situations where cleaning will be costly or difficult.
U-Value - often called the overall heat transfer coefficient and describes how well a building element conducts heat. Our standard triple glazed units have a U-Value of just 0.5 meaning that a Stella rooflight can achieve exceptional overall u-values from as low as 1.1.