Different types of glass

Float glass

This is standard clear glass. Most glass types begin as clear float. Most units will have a pane of clear float that has no additional coatings or properties. Usual thickness for glazing is 4mm but 6mm and 10mm are also available.

Low iron glass

This is the same as float glass but it is made from purer grade raw materials that have less iron content. It has a more transparent clearer appearance and allows a higher level of solar heat gain transmission known as ‘g’ factor/value (direct heat from the sun) through it. It is used to attain a better window energy rating (WER) as the solar gain factor (g) is used as part of the WER calculation. When used, it is used instead of the clear float glass pane. It has no low e properties.

Low e glass

This is float glass with a coating applied to one side (the coated side goes inside the unit). Low e (low emissivity) is the term used to describe these coatings and they have the effect of reducing the heat transmission through the glass by reflecting it back into the room.

There are two types:

Hard coat

This coating is applied to the glass as it comes out of the float production line and fuses to the hot glass. The term ‘hard coat’ is used as the coating is durable and in effect hardened onto the glass.

Soft coat

This coating is applied to cold glass by a ‘magnetron’ coating line. The float glass is passed through this special facility and the coating is applied to the surface. This coating is delicate and damages quite easily and thus the term ‘soft coat’ is used to describe this type of low e coating. The soft coating has to be ground off around approximately 15mm of the perimeter of the surface of the glass to enable the sealant to bond direct to the glass. This is called edge deletion.

Soft coat glass out performs hard coat glass in thermal insulation terms.

Obscure glass

As the name suggests, obscure glass is used to create a degree of privacy in areas such as bathrooms. Glasscraft have a range of obscure, patterned and privacy glass in many designs with all patterns being available in 4mm glass.  They can also be toughened if required.  Full information and for different widths, laminating and sandblasting, please click here.

Tinted glass

This is float glass that has a colour tint added to it in production: bronze, blue, green or grey. This is in effect opposite to low iron glass described above. This glass is used to stop the solar heat gain (g) entering the room and works by adsorbing some of the heat from the sun.

Solar control glass

This is standard float glass with a special solar control coating applied to it in a similar way to low e products. The coating in effect reflects the heat back, preventing it from entering the room. There are solar control coatings that are combined with low e coatings and offer the dual function of solar control and low e on one piece of glass.

Lower maintenance glass

There are two types: reactive coated glass and secondary applied.

Reactive works by reacting with UV light from the sun which breaks down organic dirt and debris. When it rains the dirt is washed off.

The secondary applied products are non-stick coatings sprayed on the glass. They do not react with UV. Again, rain washes the dirt off.

In our opinion the reactive and applied are as good as each other. Both need regular rain fall or rinsing to wash away dirt. This does not mean that you will never need to wash your windows! However, it should reduce the frequency.

Toughened and laminate safety glass

All of the above glass types can be toughened in-house, using our state-of-the-art toughening plant. This is accredited to and stamped EN12150. Bioclean low maintenance glass must be toughened to activate the low maintenance coating. For further information please click here.

Many of the above glass types are also available as laminated safety glass. This comprises of two pieces of glass bonded together with a resin/pvb layer. When the glass breaks, it remains in one piece. We stock the more common types of laminate glass including:

• 6.4mm clear
• 6.8mm clear
• 10.8mm clear
• 6.4mm Planitherm Total+
• 6.8mm Acoustic (noise reduction)

 Other sizes and toughened laminate are available to order with a longer lead time. For further information please click here.