Structural glazing uses glass as a fundamental, weight-bearing component of the building and bonds it directly to the structure using adhesives like structural silicone. Non-structural glazing treats glass simply as an enclosure or filler, relying entirely on heavy visible frames (like aluminum mullions) to bear all wind and structural loads.
Curtain walls are described as non-structural outer walls, while structural glazing involves bonding glass to the building structure.
Structural glazing systems, in their simplest form, are types of curtain wall systems consisting of glass that is bonded or anchored back to a structure without the use of continuously gasketed aluminum pressure plates or caps.
Perhaps the earliest example of structural glazing is glass block – developed in the early 1900s to bring more light into industrial spaces, this material is load bearing and used in a manner akin to masonry.
The disadvantages
Structural glazing can be expensive – especially if specified in large sheets. As well as budget considerations, access will need to be accessed. If access to the site is difficult, this may restrict the size of the panel that can be delivered and therefore installed.
The glazing of any windows, doors and roof lights to an extension should be limited to 25% of the extension floor area (plus and doors/windows being built over) The 25% rule is set by the government and is aimed at reducing global warming.
Key Benefits of Structural Glazing
This enhances occupant comfort, productivity, and energy efficiency by reducing reliance on electric lighting. Views – The seamless glass surfaces allow uninterrupted outward views that connect building occupants to the exterior environment.
They are divided into 4 categories:
A structural glass roof will have a minimum thickness of 33 millimetres for a single glazed unit whereas a double glazed structural glass facade could start with a glass thickness of 32 millimeters or double glazed unit.
Four-sided structural glazing is a unique system where the glass panels are bonded to one another on all four sides. This type of glazing excludes additional framing members, creating a more modern aesthetic. Four-sided structural glazing is ideal for storefronts, curtain walls, and other vertical glazing applications.
Glazing choices
NOTE: Product price may vary from Rs 280-380 per square feet as per quality specification.
Structural Glazing or Captive Glazing Structural glazing refers to glass that is bonded or anchored to the frame. Captive glazing uses either a glazing bead or screw-applied pressure plate (with a snap-on face cap) to “capture” or trap the glass inside the pocket.
The difference between structural and non-structural walls comes down to function: structural walls support the building, while non-structural walls do not. A structural wall, often called a load-bearing wall, is a key part of the building's framework.
Double glaze, also known as dual-pane windows, use two panes of glass separated by a spacer and air space within an opening to improve insulation against heat transfer and sound transmission. Dual-pane windows are the most common energy efficient glazing type on the market today.
The current industry standard double glazed unit is made up of one 4mm pane of “Low E” (Low Emissivity) coated glass*, one pane of 4mm plain annealed glass and a 20mm cavity of argon gas (make up = 4-20-4).
Two-sided structural glazing offers transparency and maximum safety. The glass panels are bonded on the vertical sides and mechanically fixed on bottom and top to an adapter profile.
The following will explain the most common types and their uses.
Whereas the aforementioned glazing refers to any form of glazing section within a property, structural glazing refers to any large glass panel that is integral to the structure of the building. In layman's terms, if the glazing is responsible for ensuring the structure of the building, it is structural glazing.
4mm Glass: The standard thickness for most double glazing units. It offers decent thermal insulation and is suitable for most uPVC windows and casement windows in standard homes. 6mm Glass: Thicker than the standard, offering better acoustic insulation and improved durability.
28mm Thickness: The 28mm unit offers optimal thermal insulation, helping to reduce energy costs and maintain a comfortable indoor environment. Argon Gas Filled: Argon gas between the glass panes enhances the unit's insulating properties, making it more energy-efficient than standard air-filled units.
Glazing and its Role in Windows
It can be clear or tinted float glass, tempered glass, and laminated glass, as well as a variety of coated glasses, which can be either single, double, or triple-glazed.
What is the 25% glazing rule? Simply put, the 25% glazing rule states that the glazing of any windows, doors, and roof lights to an extension should be limited to 25% of the extension floor area, including any windows or doors being built over.
Putting more than the recommended number of layers will likely give you a denser color and may result in running, though some glazes are better when 4-5 layers are applied (there are a couple of Amaco glazes that give the best results with 4 or 5 layers).