Glass Options

Associated products

Commercial use

Residential projects

Commercial projects




High Level Window Design

Clerestory windows or Overstorey Windows as they are sometimes known were historically used on the upper levels of Churches on walls that were above the rooflines of the aisles below.

Clerestories or Overstoreys are high sections of a wall that contain windows that are above eye level. The main purpose for installing these windows is to allow light and fresh air into a building as well as maintaining privacy.

IQ Glass can provide frameless structural glass windows to a high wall of a building. Commercially, these windows are perfect for gyms or train stations as they can provide a lot of natural light into a large space. Residential projects that are much smaller can also benefit from these windows as we can provide a section of bespoke narrow windows along the top of a wall.

Frameless Windows

Invisio Clerestory or OverStorey windows are the perfect solutions for maintaining wall space as well as providing natural light into the building.

These frameless windows can be made from a variety of technical glass including sandblasted glass or decorative glass. Sandblasting the clerestory windows can help enhance the privacy aspect.

IQ Glass can provide frameless clerestory windows to help maximise the natural light intake and enhance views of the outdoors. Opening aluminium windows or slim framed sliding windows can be integrated for ventilation.

Clerestory or Overstorey windows are ideal for areas where natural light and ventilation are required as well as a necessary amount of privacy such as a bathroom.



Maximum Sizes

IQ Glass creates frameless clerestory or Overstorey windows using structural glass technology and they are designed bespoke to suit the size of the area they will be installed in.

The maximum size per glass panel used to create these high-level windows will depend on access for the installation and any weight restrictions on site.

If there are no other factors to consider the biggest piece of toughened glass produced in the UK is called a Jumbo Sheet which is 6m by 3m.


Glass Specification

These frameless structural glass windows are available in a double or triple glazed unit as required. The exact glass specification will depend on the size of the glass units, the wind load of the project and any other performance criteria we have to consider, however, the typical thermal performance of the glass will be a Ug value of 1.1 W/m2K for a double glazed construction and Ug 0.7 W/m2K for a triple glazing unit.

These windows can be made from a variety of technical glazing products including low iron glass, coloured or decorative glass, anti-reflective glass, privacy glass, electrochromic glass or sandblasted glass. Coatings and finishes can also be applied including solar control coatings and low maintenance coatings.



Integrated Openings

If ventilation is required from these high level windows it is possible to design a minimal and aesthetically attractive clerestory window by integrating opening elements within the structural glass window.

Slim framed sliding glass doors will give you the most minimal appearance with a frame of 21mm which fits in with the minimal sightlines of structural glass assembly well.

Hidden motors and electromagnetic locks can be used with these sliding windows to allow easy control of the ventilation, opening and closing actions even when the windows are at high level.

Alternatively we can integrate aluminium or steel casement windows within the structural glass installation for ventilation. These opening windows would generally be top hung in these narrow high level window constructions.

Again, electrical actuators for remote opening are able to be integrated within the steel or aluminium window for easy ventilation in hard to reach windows.


ASK US ABOUT OUR Clerestory Windows by Invisio®


Commercial use

Commercial Projects

Clerestory or Over storey windows are quite popular in commercial projects as these buildings are normally much larger and will need as much natural light intake as possible.

These frameless windows can be found in churches and offices. Clerestory windows can be designed in a variety of ways, helping them to match the design of the building perfectly. In churches, these windows are made in a variety of shapes however, in offices these windows can be used to create a complete wall section of glass above eye level.

In offices, using sandblasted glass for the clerestory windows can be ideal as you are able to maintain the privacy of your office whilst still allowing natural light into the building. Decorative glass is usually the best choice for churches as you will be able to create a stained glass finish, matching the other windows in the building.

IQ Projects is the specialist commercial division of the IQ Group - www.iqprojectsuk.com

Featured Project

Warwick Hall is a listed building in West Oxfordshire that underwent a large redevelopment to extend the community space attached to the Grade II listed Church.

Clerestory windows, along with slim framed glass sliding doors and frameless rooflights were installed into the hall to maximise the natural light into the space as well as providing views of the church and other scenery around the building.

The minimal framing of these clerestory windows match with the other glazing involved including minimally framed sliding glass doors, glass balustrades and frameless rooflights.

These windows were installed due to lack of space on the building for normal height windows. Although there are sliding glass doors installed into the hall, they do not provide a lot of light due to the corridor being closed off. These clerestory windows were installed to provide the natural lighting that the hall would have originally lacked.

You can read more about the Warwick Hall project here.



Invisio Structural Glazing Brochure


Invisio Clerestory Windows Product Data Sheet


Invisio Structural Glazing Brochure