Guillotine glass is an enclosure system in which the glass panels move vertically rather than horizontally. The panels are lifted upwards by a mechanism concealed inside the aluminium cassettes at the sides and stack above one another at the top. Fully open, no vertical profile, rail or sash remains in front of you; the opening is entirely free. In this article we look at how guillotine glass works, when it is the right choice, and what to watch for in making an outdoor space livable all year round.
The working principle takes its name from the guillotine window. Each glass panel moves vertically in guides inside the side cassettes. Two common methods provide that movement: a counterweight system and a motorised system. In the counterweight solution the panel's weight is balanced by a counterweight inside the cassette; the panel lifts easily by hand and stays at whatever height you leave it. In the motorised solution movement comes from a tube motor, controlled by remote, wall button or mobile app.
The clearest advantage of guillotine glass is that it leaves the floor and side areas completely free when open. In sliding glass systems the sashes pile up at one edge when opened; that section stays permanently closed and unusable. In folding glass systems the sashes gather like an accordion and again form a stack at one edge. With guillotine there is no such loss; because the panels rise upwards, the full horizontal width of the opening stays usable. On narrow balconies in particular, this is a decisive difference.
The second key advantage is graduated ventilation. Because you can stop the panels at any height, you can leave the lower part open and keep the top closed for controlled airflow. Cool air entering from below pushes warm air upwards, giving you a way to cool the space without opening it fully. In sliding systems ventilation is limited to the sash opening and cannot be tuned this finely.
Guillotine glass also stands out on the view. In the closed position the horizontal joint lines between panels are slim and can be planned to fall outside eye level. In sliding systems the vertical frame of every sash divides the field of vision. On terraces with a sea, forest or city view the difference is noticeable; guillotine glass cuts the view with a horizontal line rather than breaking it up with vertical bars.
Safety in glazing is the most critical heading in outdoor systems. Standard float glass is not used in guillotine applications; 8 mm tempered glass is generally preferred. Tempering makes the glass roughly four to five times stronger than ordinary glass and changes how it breaks: tempered glass shatters into small blunt-edged granules rather than sharp shards. On upper floors and in areas with children, laminated glass - where the pieces stay bonded to an interlayer - is also worth considering.
Sealing is the question people ask about most. Brush gaskets sit between the panels and inside the cassettes; they reduce friction as the panels move vertically and block wind and dust in the closed position. A brush gasket is not as airtight as the EPDM gaskets in door and window systems, so guillotine glass creates a sheltered semi-open area rather than a heated interior. For winter use it needs to be planned together with an infrared heater.
Cleaning is a heading often skipped when choosing a system. On standard guillotine glass, the outer face of the panels is hard to clean on upper floors because it cannot be reached from outside. Tiltable guillotine glass solves exactly this: because the panels tilt inwards, you can safely wipe the outer face from inside. On upper floors and wind-exposed façades we treat this feature as a standard requirement.
Guillotine glass does not suit every opening; there are dimensional limits. As a panel gets wider it gets heavier, increasing the load on both the mechanism and the cassette. Wide openings are therefore solved with several modules rather than a single panel. Panel height matters too: since the panels stack at the top, there must be enough cassette height above. During the survey we assess the opening's width, height and the clearance above together.
On installation, the critical point is fixing the cassettes to a sound structural element. Guillotine glass cassettes carry both their own weight and the moving load of the panels, so anchoring must go into a reinforced concrete beam, column or shear wall. A cassette fixed only into aerated concrete or hollow brick may look fine at first but shifts over time and disturbs the smooth running of the panels. That is why we check the façade's load capacity specifically during the survey.
Guillotine glass should be considered as part of a system, not on its own. When a glass roof or bioclimatic pergola above, guillotine glass at the sides and zip screens where needed come together, the outdoor space becomes a sheltered volume in any weather. Planning that whole from the start matters; when colour, profile line and automation logic match, the result reads as one architectural piece.
Comparing it with other glass systems makes the choice easier. Sliding glass is more economical on long façades and leaves a wide passage when fully open, which is practical where direct access to a garden is wanted. Folding glass gathers the sashes at one edge and frees almost the whole opening. Guillotine glass comes into its own on short, wide façades and wherever the view and the floor area matter.
Maintenance covers three components: the glass surface, the guides and the gaskets. Glass is wiped with standard glass cleaner and a microfibre cloth; abrasive sponges and metal scrapers should not be used. Dust and sand collecting in the guides inside the cassettes make panel movement harder, so cleaning that part regularly extends the mechanism's life. Wiping dirt off the brush gaskets with a damp cloth preserves the seal.
Counterweight and motor adjustment, by contrast, require no user intervention. Whether the panel holds properly at the top, moves under control on the way down and whether the motor recognises its limit points correctly all depend on settings made by the service team. A panel sliding on its own or not closing fully usually comes from these settings drifting, and is resolved by a short service visit.
Who is guillotine glass right for? It suits homeowners with narrow balconies who do not want to lose floor space, terraces where the view matters, cafés and restaurants wanting to use their outdoor area through the season, anyone building a winter garden, and those seeking safe cleaning on upper floors. On long façades and jobs where budget is decisive, sliding glass may be the more sensible answer.
In summary, guillotine glass is an enclosure solution that takes no floor or side space thanks to its vertical movement, provides graduated ventilation and does not divide the view. Getting it right requires tempered glass, cassettes anchored into reinforced concrete, modules sized to panel weight, and the tiltable model on upper floors. You can review our guillotine glass systems and we can work out the right solution for your space together.
To find out whether guillotine glass suits your balcony or terrace, request a free site survey.
Frequently Asked Questions
No. Because the panels rise and stack above one another, they take no space from the floor or sides; the full horizontal width of the opening stays usable.
On the tiltable guillotine model the panels tilt inwards, so you can wipe the outer face safely from inside. We recommend this model on upper floors.
No. Brush gaskets block wind and dust but are not as airtight as an EPDM-gasketed window; for winter use it should be planned together with an infrared heater.
