Types of Glass Explained: Float, Toughened, Laminated, IGU
The 4 glass types you meet in an Adelaide home are float, toughened, laminated, and insulated glass units (IGUs). Float is the standard annealed pane used in most fixed windows and cabinets. Toughened (tempered) glass is heat-treated to be roughly 5 times stronger and shatters into blunt granules, so it is the safety glass used in doors, shower screens, and balustrades. Laminated glass bonds 2 panes around a plastic interlayer that holds shards in place. An IGU seals 2 panes with a spacer for double glazing. Glass is priced per square metre by type, thickness, and edgework.
Key takeaways
- Float (annealed) is the cheapest, standard glass for fixed windows, cabinets, and picture frames.
- Toughened glass is about 5 times stronger than float and breaks into safe granules, so it is a Grade A safety glass.
- Laminated glass holds broken shards on its interlayer, adds acoustic and UV benefits, and is used for overhead and security glazing.
- IGUs (double glazing) seal 2 panes with a spacer and gas fill to cut heat transfer and noise.
- Pricing is per square metre and rises with thickness, toughening, lamination, and polished edges.
Float glass: the standard starting point
Float glass, also called annealed glass, is the basic clear sheet produced by floating molten glass on a bed of tin. It is what sits in most fixed picture windows, glazed cabinets, framed artwork, and older single-glazed timber windows across Adelaide. It is optically clear, flat, and the least expensive glass per square metre, which is why it remains the default where safety glazing is not required.
The trade-off is how it breaks. Float glass fractures into long, sharp shards, so it is not permitted in doors, shower screens, low windows, or anywhere the building rules call for safety glass. When a plain float pane cracks in a window, the standard fix is a like-for-like replacement pane cut to size and reglazed into the existing frame.
Float is also the base material for the stronger types below. Toughening and lamination both start with a float pane and add a process, which is part of why those products cost more per square metre than the plain sheet.
Toughened and laminated: the 2 safety glasses
Toughened glass is float that has been heated and rapidly cooled, locking the surface into compression. That makes it roughly 5 times stronger than the same thickness of float and, critically, it breaks into small blunt granules instead of shards. This is the safety glass used in frameless shower screens, glass balustrades, sliding and hinged glass doors, and pool fencing. Toughened panes cannot be cut or drilled after treatment, so every hole and cutout is set before toughening.
Laminated glass sandwiches a tough plastic interlayer (usually PVB) between 2 panes. When it breaks, the shards stay bonded to the interlayer rather than falling, which is why laminated is specified for overhead glazing, shopfronts, and security or acoustic applications. The interlayer also blocks most UV and dampens noise, a real benefit on busier Adelaide roads.
Both are recognised safety glasses. Toughened is the common pick for wet areas and balustrades on cost and clarity; laminated is preferred where falling glass or forced entry is the concern, and the 2 are sometimes combined as toughened-laminated for the highest-demand jobs.
IGUs and how glass is priced
An insulated glass unit (IGU) is 2 (occasionally 3) panes sealed around a spacer bar, with the cavity filled with dry air or argon. This is what double glazing physically is. The sealed cavity slows heat moving through the window, which matters in Adelaide summers and cold winter mornings, and it cuts outside noise. IGUs are made to order and, once the perimeter seal fails and the unit fogs internally, the whole sealed unit is replaced rather than repaired.
Glass is quoted per square metre, and the rate climbs with each added property: thicker glass costs more than thin, toughened costs more than float, laminated more again, and an IGU more than a single pane. Edgework adds to it too, since a polished or bevelled edge on an exposed panel is extra over a plain seamed edge.
Because specification drives the price so heavily, the practical move is to confirm exactly what each pane needs (type, thickness, edge, and whether safety glass is mandatory) before comparing quotes. We connect you with vetted local glass suppliers so you can compare 3 free quotes on a like-for-like specification.
Ready to get real numbers? Compare 3 free quotes from vetted Adelaide specialists for glass splashbacks.
Frequently asked questions
Toughened glass is one type of Grade A safety glass, and laminated glass is the other. Both are accepted where safety glazing is required because of how they break, toughened into blunt granules and laminated by holding shards on its interlayer.
No. Toughened glass cannot be cut, drilled, or edge-worked once it has been treated, because any cut releases the locked-in stress and shatters the pane. Every size, hole, and cutout is set on the float sheet before it goes through the toughening furnace.
Double glazing uses an insulated glass unit (IGU), which seals 2 panes around a spacer with an air or argon cavity. The individual panes can be float, toughened, or laminated depending on whether safety glass or extra acoustic performance is needed for that opening.