H o m e

double glazed glass

An introduction to Double Glazed Units & Stained Glass Encapsulation.

This page is here to help you with understanding double glazed units, otherwise known as insulated glazing.

There are lots of different options for double glazing to choose from depending on the customers requirements.

You will need to inform us the following-

* What thickness unit they require.
* What Spacer Bar they wish to use.
* If the unit is to be Gas Filled
* What type of glass they wish to use (example low e)

Below we will supply some useful instructive advice on how to acquire the above information for your own double glazed unit.

Unit Thickness

Units are made up with two panes of glass either side a spacer bar, our typical glass thickness is 4mm (sometimes 6mm), and spacer bars start from a thickness of 6mm going upwards to 20mm, spacer bars come in the following sizes:

6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm

Making a 14mm unit for example, you would have two 4mm panes of glass, and a 6mm spacer, displayed as such: 4/6/4 Unit.
You will need to check your frame/door to see what double glazing is required.

Gas or Air Filled

A double glazed unit consists of two glass window panes which is separated by a vaccum, either air filled or gas filled.
Whats the difference between air filled & gas filled?
Air filled is the cheaper option, and do provide a certain level of enegry efficiency & noise reduction.
Gas filled is a better investment for long-term energy efficiency & performance.

Spacer Bars.

Spacer bar, otherwise known as a profile; is the continuous hollow frame which separates the two glass panes within a double glazed unit.
The bar is bonded to the glass panes via a primary & secondary seal, which inturn creates an airtight cavity which can be filled with air or gas.
The spacer bar itself is filled with a desiccant to absorb any residual moisture within the cavity and thus prevent condensation within the double glazed unit.

There are a few spacer bars to choose from, we will start with the most popular,

Aluminium- Light but strong their flexibility means they can be formed into a wide variety of shapes and sizes. However, less effective in insulating against heat loss than warm edge spacer bars, these Aluminium spacer bars are the more cost effective of the spacer bars.

Warm edge spacer bar- otherwise known as thermal break, reduce the heat loss around the perimeter of a double glazed unit by replacing conventional aluminium with low heat conductive material,
further reducing condensation on the room-facing surface of the double glazing window as they transmit less of a temperature difference to the interior plane.
Usually made from a fibre-glass reinforced insulation material. An ultra-thin foil lining acts as a barrier to the gas or air trapped within the cavity.

These are available in different colours, including brown, white, silver, black.


Low E- Otherwise known as low-emissivity glass, with a transparent metallic coating that works in two ways to economise heating energy. The dual action coating reflects heat back into the room whilst allowing heat and light from the sun to pass through.

Pilkington K Glass™- A low-emissivity soft coated product which offers thermal insulation when incorporated within an insulating unit, with optimal solar heat gain, thermal insulation and light transmission to provide the highest window energy rating.

double glazed units

Fitting Your Double Glazed Unit

Replacing a double glazed unit is a simple procedure, here we will look at fitting.

There are a few tools you'll need in this process-
• Neutral Cure Silicone • Glazing Blocks Otherwise known as Spacers • 1mm Double Sided Backing Tape/Butyl Strip/Rubber Strip •Beads •Nails •Hammer •Scissors

The double glazed unit should measure 6mm LESS than the tight size of the aperture.
Firstly presumming you have removed the previous unit and its beading, the inside of the frame should be bedded with glazing blocks (these can be found at any DIY store), the double glazed unit should be then set onto the glazing blocks bedded onto either rubber strip or butyl strip, then seal with Neutral Cure Silicone. Please bear in mind that no other type of silicone should be used as this will affect the seal on the double glazed units, and will void your warranty with the double glazed unit manufacture.

encapsulated stained glass

Stained Glass Encapsulation

Encapsulating stained glass is different from double glazing.
Encapsulating the stained glass panel is sandwiched between two panes of 4mm glass, depending on desired insulation, either soft coat glass can be used or clear.
Depending of which option is required prices will differ. Please be aware encapsulated stained glass panels cannot be gas filled.

There is a photo displayed to the right that shows a small stained glass panel encapsulated.
As you can see around the edges there is some butyl sealant (which is black) followed by the aluminium bar, before the actual lead lines/ stained glass design starts.
This means that there is a 12mm band around the edge of all the glass, so the design has to be reduced to fit within these sizes.
As for encapsulated unit thickness, the minimum thickness of these units is 20mm.

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*All goods will be supplied subject to VAT @ 20% When ordering any glass off our website please make sure you provide the correct sizes including the correct tolerances. We can not take any responsibility for sizes that have been provided incorrectly! Information on glass sizes can be found on our MEASURE UP page, or if you require any further information on measuring up please contact us we are always here to help.