The Art of Installing Large Glass Panels: A Technical Journey with KAV

In recent times, we have shared several recordings depicting the installation process of large glass surfaces as part of KAV’s daily operations. To shed light on the distinctions in window installation and preparation when incorporating larger glass sizes into a property compared to standard glass dimensions, we interviewed Mr. Péter Nagy, Senior Engineer, and Mr. Károly Lovász, CEO of KAV.

NP: The installation of large glass surfaces necessitates meticulous pre-planning, distinct from the usual window application, and requires specialized manufacturing processes and work organization. When executed appropriately, the installation of jumbo glass panels becomes a more straightforward task. Naturally, it is imperative to bring the attention of our clients to the fact that the cost of large glass sizes is exponentially higher, and even the fabrication and installation of the supporting structures are not straightforward. Unfortunately, domestic manufacturers often struggle to produce these sizes, which is why we sometimes have to resort to imports. Abroad, glass processors equipped for this purpose can effortlessly manufacture tempered, triple-layer glass panels measuring 3.2×7 meters. Furthermore, a German company, owing to its specialized tempering furnace and infrastructure, can even produce insulated glass panels measuring 3.2×13 meters.

Today, we typically discuss manufacturing sizes ranging from 3.2×5 meters for average glass surfaces. For this size range, major domestic manufacturers are adequately prepared up to a certain weight limit. However, for larger tempered glass surfaces or those exceeding specific weight thresholds (as automated production lines cannot withstand the load), a separate approach is required. For instance, the recent large panels we installed weighed around one and a half tons each, featuring considerable thickness and a special layering. Since these panels were installed in exposed locations and positioned upright, they had to withstand substantial stress. Consequently, we had them manufactured in Poland, ensuring color consistency, and shipped all other glass panels for the project from there. We always order glass from a single manufacturer for each building, and if replacement glass is required due to breakage or potential warranty issues, we order from the same manufacturer. This is a fundamental rule we adhere to.

LK: The initial step in pre-planning involves comprehending the architectural concept, followed by the design of window structures and the planning of operable and lockable surfaces based on this concept. During client consultations, which we refer to as “needs assessment” at KAV, we clarify the type and quality of windows the client wishes to see, the visual effect they desire after the finishing of interior surfaces, how they intend to use these spaces, what elements they wish to motorize, and what they do not. Once we have established where we open and close, the height we can achieve with each panel, and the aspects to consider in terms of shading technology, fine-tuning follows. This is when we calculate the weights and consider the weight distributions caused by the glass panels. We need to understand how to address the load-bearing elements beneath them, whether dynamic loads need to be considered, if the structure can bear the weight, or if alternative solutions are necessary, possibly involving the assembly of multiple smaller pieces. We refine the design until a solution is reached that the client accepts and we can professionally endorse. Subsequently, genuine planning takes place, including considerations such as drainage and dynamic movement – for instance, when moving a 700-kilogram sliding sash in front of a fixed one, the weight increases to one and a half to two tons. We also plan the weight transfers and junctions. Afterward, we coordinate this with the builder and, if it aligns with their requirements, with the general contractor and project manager as well. The finalization of plans is followed by specialized planning, and after the building’s structural elements are in place, we conduct a survey. At KAV, we no longer rely on traditional measuring methods but instead utilize 3D scanning of the building, with our engineers working with point clouds. The building’s characteristics determine what we can achieve since windows must function harmoniously with other elements of the structure. If the building cannot bear the load or requires substantial structural reinforcements, we may have to advise the client against using large glass panels, as it would entail significant costs and time.

NP: With large glass panels, traditional aluminium window manufacturing practices must be set aside. These structures involve heights and widths that can only be achieved through bespoke construction. During pre-planning, numerous bespoke constructions, components, supports, and expansion joints, as well as 3D-printed details, must be devised, which we either produce ourselves or source from external suppliers. Uniqueness is the key factor that permeates the entire process, from design through manufacturing, packaging, to transportation. For instance, during transportation, larger elevated structures may not fit under bridges if placed on conventional trucks and standard supports. Another critical aspect is glass bonding: we manufacture the frame systems and frameless sliding or bonded-opening structures for the large panels in our Kisbér facility in two phases, then transport them to the installation site. This is referred to as two-stage transportation due to the time lag, which demands sophisticated logistics. Additionally, it’s worth noting that in some cases, it may be necessary to airlift a window, which might even prove more cost-effective than road transportation. We explore every possibility to find the best solution, one that imposes the least burden on the local community, as these installations always take place in residential areas. Naturally, we must also consider future glass replacements, as glass, being an amorphous solid, can easily break. It is not elegant to dismantle a completed garden due to glass replacement, so this aspect must be clarified with the client during the planning phase.

LK: From this discussion, it becomes evident that the time-consuming aspect of large glass installations is not the installation itself but rather the operational and administrative processes, which must be meticulously planned to eliminate margin for error. In the case of the building shown in the video, the installation of the frame systems took approximately three weeks before the final securing and sealing of the aluminium structures and glass surfaces. The process concludes with the mechanical and electronic assembly of all window systems, followed by their trial operation. We hope that this explanation helps our clients understand that, without specialized planning, there is no shortcut for special or large window installations. Every architect would prefer to bypass this step, as it incurs costs, but the necessity of specialized planning must be acknowledged.