Sealed Units

A sealed unit is a construction of 2 panes of glass spaced apart with a spacer bar made to form a cavity between the panes.  A dessicant is incorporated in the spacer bar to dry up any residual moisture.  An edge sealant is then applied to all four sides to form an airtight seal.

We offer Swiss warm edge bar in various colours from 8mm up to 20mm, we also stock aluminium spacer bar from 4mm up to 20mm in silver, black, bronze, white and even gold.

We manufacture any combination of glasses including energy efficient low e, toughened safety glass, accoustic and self cleaning glasses with many more options available.  Argon gas filling is also available to give greater thermal insulation performance.

We also manufacture triple glazed units which are the same as above using three panes of glass, a triple glazed unit is better for insulation than a double glazed unit and from a safety point of view harder to break, we can also insert your old (or new) traditional leads into triple glazed units making them easier to clean and protect.

Slimline units are a new concept in double glazing popular with joiners in conservation areas to replace single glazing with energy efficient slimline double glazing.

All our units are made inhouse and tested yearly to current manufacturing specifications as listed on our homepage and are guaranteed for 5 years subject to glazing conditions.

Triple Glazed Units

A triple glazed unit is made up of three panes of glass, each pane is separated by a aluminium spacer bar. The smallest triple glazed unit that we can manufacture is 20mm overall, after this the thickness goes up in 2mm intervals.

A triple glazed unit is better insulated than a double glazed unit. A triple glazed unit can also reduce the opportunity for condensation to form as you have two aluminium bars inside the unit as opposed to just one with double glazing, this means you are getting double the desiccant inside the units.We can also offer the service of encapsulating existing original stained glass inside a triple glazed unit, with the leaded glass replacing the centre pane inside the sealed unit.

Slimline Units

LEAD DESIGNS have been manufacturing double glazed sealed units in the South London area for over twenty years and are now proud to announce their new SLIMLINE UNITS.
SLIMLINE units are a new concept in the construction of double glazed sealed units in line with the growing concerns for carbon emissions and improved thermal insulation it is now possible by using and maximising the latest technology to construct  a double glazed unit with a very small cavity using 4mm clear float or toughened safety glass and insulating inert gas, which only performs in smaller cavities and an inner pane of  4mm low emmisivity float or toughened safety glass with a dual seal for added gas retention the new slimline unit reduces the required glazing width rebates and enables slimmer rebates to be used which in return is beneficial to all window joiners as less wood is used.
The new SLIMLINE unit is in compliance with current building regulations BSEN 1279 and DOCUMENT L
Our standard SLIMLINE unit is made to the following specifications
  • U.VALUE 1.8
Other configurations available please email or fax your requirements for sameday estimate.
All SLIMLINE units are made in-house for excellent lead times
No minimum order value

Conservation Bar Units

We specialise in manufacturing units with integrated spacer bars to give the effect of multi-pane units to replace older style windows in listed buildings and conservation areas for that authentic, traditional look. This is very popular with joiners.


Contact us for a free quote on 0208 646 7355

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