July 8, 2020

Strategic Use of Roof Glazing

Written by Rebecca Clayton

HIRT descending windows LA
Roof glazing is a great architectural glazing solution to bring light into internal spaces. Having glass within the roof means that you can achieve optimum light ingress throughout the day, something that is not possible with vertical glazings such as frameless glass walls or sliding doors.

As with all architectural glazing, the use of glass within a roof should be carefully considered. You want a good balance of natural light against privacy and solar gain.


A recent project in Cambridge showcases a well-considered application of structural glass roofing.

The project was designed by Neil Dusheiko Architects. Large sliding doors provide a good connection between inside and out on the rear elevation, however the two strip rooflights within the extension roof provide a large amount of natural light.



The rear frameless rooflight acts as a connection between the new extension and existing house. It offers a bright strip of natural light further back within the home, allowing light travel deep into the home.



At the back of the garden sits a small, hidden garden spa building. This space was designed to be darker and cave-like. As such the roof glazing in this space was more minimal. Two single rooflights were installed in strategic locations within this space, providing overhead light in key areas of the garden spa room.

portland road roof glazing and floorlights underneath Another recent project – Portland Road – used roof glazing in thought-out positions to provide a column of natural light that penetrated through multiple floors. Various rooflights were installed within the roof of the multi-storey townhouse with internal glass floorlights inside. This internal glazing, paired with the roof glazing allowed light to flow through the building, all the way to the basement spaces.

A similar design concept was used on Britten Street which included an automated sliding rooflight paired with internal glass floorlights to allow light to travel through the multi-story house.






This modern automated rooflight system offers a unique approach to roof glazing. Opt for this system if roof access is required, or for a system that seamlessly integrates within a smart home automation system. Unrestricted on sizes, the MARS has been developed and designed in house to offer specialised opening solutions. Adaptability is at the forefront of this product, ensuring we can meet any special design requirements.

Full Glass Roofs

Larger glass roofs can be used to great effect as well, creating bright spaces well connected with the outdoors.

glass roof over basement


This basement extension in London by Guttfield Architects includes a full glass roof over the updated space. As there are no side windows or another glazing, the large glass roof ensures the space receives the natural light it requires to be a useable living space.

The structural glass roof is supported with a structural glass beam, offering a fully glazed structure and design.

Roofs in Glass Extensions

This steel-framed glass extension in London shows an alternative design to your traditional ‘glass box extension’. The steel glass roof and steel-framed glass wall create a bright seating and reading area on the first floor of the property, offering lots of natural light and great views over the large garden.


steel framed glass conservatory


This rooftop glass extension in South London showcases an alternative design for a glass structure. This glass roof was completely frameless, supported by glass beams. The all-glass structure again offers large amounts of light to enter the internal space which acts as an additional sun trap living roof for the owners of the flat.


roof top glass extension


Glass Specification for Glass Roofs

As well as the size and location of roof glazing, careful consideration should be paid to the specification of glass within the roof.

For insulated glass roofs, a double glazed unit with low e coating and argon gas filling is a basic must-have. All external glazing from IQ is specified as standard. Triple glazing is also possible.

large glass roof on barn extension We recommend some form of solar control coating on all roof glazing installations. As these installations of structural glass are under direct sunlight for most of the day, a solar control coating is always advised to minimise the effect of solar gain.

All glass within the roof should be toughened as standard. The internal pane of any overhead glazing should be toughened laminated glass for safety. You can read more about that here.

All fixings and connections to the building should be created using a thermally broken system. At IQ we use our exclusive Invisio structural glazing system for all roof glazing. This provides the roof glass with a fully thermally broken connection to the building, ensures proper thermal performance is maintained and stops any cold bridging.

What Next?

If you are looking at including roof glazing on your project speak to the team at IQ who can assist with the specification. We can offer typical CAD details, costs, and advice on the glass specification and fixing. Visit our contact us page for all the ways you can get in touch. 


You can also click the following link to view all our current selection of bespoke opening and sliding rooflights and roof glazing systems