Structural Glazing

Design considerations for opening glass rooflights within structural glass roofs

Opening glass rooflight to structural glass roof

Technical guide on opening rooflights within structural glass roofs

Structural glass roofs are a popular architectural choice for creating open, light-filled spaces. Integrating opening rooflights into these structures can enhance natural ventilative cooling, provide additional light, and maintain a pleasing aesthetic. This guide provides technical insights and best practices; fundamentally the lynchpin for continued successful collaborations between IQ and architects when incorporating opening rooflights into complex structural glass roof projects.

Design Considerations for opening rooflights within structural glass roofs

An obvious design consideration is calculating the load distribution to ensure the roof structure can support the additional loads from the rooflight. This includes dead loads (weight of the rooflight) and live loads (wind, snow, maintenance). 

It is not possible to maintain a total frameless finish because reinforced framing systems are required around the rooflight openings to support the structural integrity.  However, aesthetics and functionality of opening rooflights within glass roofs must be considered so that the rooflight is seamlessly integrated to blend with the surrounding glass panels. IQ specialises in structural glass solutions including water sealing and bespoke integration. 

Water drainage for structural glass roofs is crucial, and a pitch of a minimum of 3-5 degrees must be factored into the design.  

What sets IQ apart from other glaziers is its capabilities in engineering bespoke details to create functional and unique designs. 

For Automatic Opening Smoke Vent (AOV) systems, IQ opening glass rooflight designs can be integrated into fire alarm systems in accordance with Building Regulations –Fire Safety Approved Document B. 

We can design custom opening rooflights for smoke control and ventilation – Approved Document F at the early phase of drawing where all the wiring design components are completely concealed for the ultimate minimal finish.  


Project examples of opening rooflights within structural glass roofs 

Great George Street

Opening glass rooflights to structural glass roof atrium

IQ Projects was commissioned by Barton Willmore to design and install the structural glazed atrium to the seven-storey Great George Street commercial office in Bristol. The expansive structural glass roof uses structural glass beams to support the load.  

Either side of the structural glass roof, the IQ team installed two automated opening rooflights for smoke and ventilation purposes.

The steel connections are covered by PPC bespoke pressings, templated and measured on site to conceal the construction junctions. 


Lowther Road

Opening rooflight within strip rooflight

A contemporary rear extension on London’s Lowther Road uses automation with the opening glass structural glass roof above the kitchen for ventilation.  

The size and positioning of the opening rooflight was a key design element contributing to cross ventilation principles. 

The integrated automated aluminium framed rooflight offers ease of operation, especially since it’s installed in a hard-to-reach area. 


Grange House

Opening rooflight within structural glass roof and steel glazing at Grade II listed London home

Grange House is a Grade II listed 17th Century house which used a structural glass roof with opening rooflight to the entire footprint of the extension. As a nod to its historical era, steel frames were used  

fully integrated into the original brickwork interfacing with the glass panes with integrated discreet drainage channels to rear side of the building. 

Weatherproofing, water drainage and insulation are key design considerations when designing opening rooflights with structural glass roofs. Seals and gaskets prevent water ingress and air leaks which can drastically affect thermal performance. 


Gloucester Place

Bespoke opening glass roof to structural glass roof

A large structural glass roof to Gloucester Place basement serves as both a light filled space below, and as walk-on outdoor ground floor to the outside. The structural glass is etched to prevent slipping. The clever detail is the opening glass rooflight within the the structural glass roof which is housed in a bespoke glass step for safety.  

Providing maximum light and ventilation to the basement with a structural glass roof and opening rooflight, plus the additional useable space gain with the basement roof serving as a glass floor, there is no trade off.

The opening rooflights under the glass step can be easily accessed for cleaning and maintenance, which is key for all automated glazing systems. 



Integrating opening rooflights within structural glass roofs is a complex but rewarding endeavor that requires careful consideration of structural integrity, aesthetics, weatherproofing, and general maintenance.  

Our inhouse technical engineers collaborate with architects to design and implement effective and visually appealing solutions that enhance natural light and ventilation while maintaining the structural and aesthetic integrity of glass roofs. 


Are you working on a unique design with opening rooflights within structural glass roofs? 

Contact us today! 


Further reading: 

A complete guide to design options for structural glass roofs