Replacement Sealed Glass Units

If your double-glazed glass sealed unit has failed, or just needs updating, we can provide replacement sealed glass units.

Replacement sealed units for windows or doors can be manufactured with the following options:

Glass types:
Double glazed sealed units.
Triple glazed sealed units.
Clear or obscured glass.
Toughened glass.
Laminated glass.
Single-pane pieces of glass.

Glass depth:
Double-glazed replacement sealed units are available in (overall size)
14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm,
See information below for details.

Spacer bar options:
The standard colour for an A-Rated unit is black.
The standard colour for a C-Rated unit is silver.

Sealed Units can be filled with Argon Gas.

Dog / Cat-Flap
Double-glazed glass sealed units can be cut with a hole for a dog or cat-flap. The pet flap must be round, and suitable for installed into a glass unit.
We would require the diameter of the pet flap, and location of the cut.
Please note, there must be a 90mm gap round the edge of the cut hole to the edge of the sealed unit. Therefore the sealed glass unit, generally must be at least 570mm wide in order to have a pet-flap installed (this size may be larger if pet-flap is larger)
Please note, it is not possible to cut a pet-flat into an existing glass sealed unit, a new unit must be manufactured.


When ordering sealed units, we need to know the width, height and the depth of the glass.

Replacement double glazed sealed units for our windows are:
28mm in depth (4 – 20 – 4) as standard.

Common sizes in other windows or doors are;
24mm (4 – 16 – 4)
26mm (4 – 18 – 4)
or older windows could be smaller.

The smallest standard double glazed units available are;
18mm (4 – 10 – 4) with a black spacer bar, or:
14mm (4 – 6 – 4) with a silver spacer bar.

Toughened Safety Glass

Toughened safety glass should be used in:

Any bathroom,
Any unit within 300mm of a door,
Any unit below 800mm from floor height,
Any roof glass.

Obscured Glazing

Our PVCu windows and doors are available with a wide selection of obscure & texture glazing.

Browse our obscure glass selection

Minimum and Maximum Sizes

The minimum size possible for toughened glass is more than 250mm on at least one dimension (width or height). If both width and height are less, glass will need to be annealed or laminated.

Any unit over 1400mm in both directions (width and height) must be made in 6mm thickness.

Any unit over 1300mm in both directions (width and height) should have a 12mm cavity.

Any unit over 2.90m2 must be in 6mm thickness.

The maximum unit weight is 114kg and the maximum size limit is 3.80m2 or 2.53m2 if triple glazed.

Any unit over 1900mm in both directions (width and height) cannot be manufactured.

Glass sheets are 3210mm in width, so units with either dimensions more than 3210mm cannot be manufactured.

Patterned glass is available in a maximum of 1320 X 2140mm. The only patterned glass available above this size is Satin.

6 mm patterned glass is only available in: Autumn, Cotswold, Everglade, Flemish, Stippolyte and Satin.

Below is a guide for the minimum and maximum glass sizes and thicknesses. On larger units in 4mm, flex is possible, so 6mm should be considered, if required, although again flex may be evident.