This glass box extension was installed onto a home in Hampstead, London as part of a rear refurbishment. The glazing elements used were made with low iron structural glass. The glass extension utilised the low iron glass to stop any ‘greening’ from occurring in the structural glass beams. The structural glass supports on this glass box extension were fixed to the ‘listed’ brick work using heavy duty clamps of stainless steel.

The homeowners required a fully glazed extension to pass the building regulations for their listed building. By having a fully glazed extension with no framing allows the traditional brick building to be viewed through the new extension.


A set of bespoke flush glazed doors were installed onto the extension to provide access between the internal and external areas.

These doors were designed to sit flush against the other structural glazing with no protruding frame for a seamless, flush design throughout the extension.


Structural glass beams and fins were integrated into this glass extension to provide structural supportLow iron glass was used to make these glass beams and fins to prevent them from ‘greening’. These were used as support instead of slim metal beams as they allow all natural light to pass through into the extension and reduce any obstruction to views of the brick building and garden.

Black back painting was used, creating a contemporary aesthetic to the extension and contrasting with the traditional brick building. This back painting was used to hide all fixings and silicone seals used to connect the structural glazing together. This back painting creates an almost framed effect whilst allowing the extension to be completely flush.