When considering a bespoke design package, it is imperative that a design sales meeting is conducted to ensure that all aspects of a glass structures design is considered. There are huge advantages to a structures aesthetics and performance, when considered and every effort should be made to ensure that the design brief meets the client’s expectations.
We have listed many of the main considerations when utilising frameless glass systems in architectural glazing below.
Frameless Glazing is often more costly than the other typical systems available (unless the glass is shuffle glazed or self supporting). Frameless Glazing is typically 20% - 30% more expensive than that of a Structural Glazing equivalent and 45% - 55% more expensive than Framed Glass (Curtain Walling/Patent Glazing) solutions.
Despite this systems name, frameless glazing systems do require a small amount of perimeter framework. Any structural glass fins will also typically require structural fixing brackets, splices and sometimes glass fittings. Frameless Glazing systems often require thicker glass than that normally required. Making handling, site access and lifting equipment important considerations. Should the glass design require windows, doors or roof vents (typically framed), care should be taken to ensure that these items add and don’t detract from the overall appearance. The glass units are provided with a black spacer and silicone seal as standard. It is worth noting that polysulphide sealed glass units are not suitable for frameless glazing applications due to the exposure to UV light. Float laminated glass can not be utilsed in this application and should a laminated inner pane be required, a toughened laminated glass should be utilised.
As frameless glazing systems do not rely on internal weep systems and subsequent drainage, they may be installed at as low as 3-5 degrees pitch (subject to application).
It is worth noting however that the size of the water beads that will retain (‘cling’) to the surface of the glass will increase exponentially to a reduction in pitch.
If your frameless glazed structure requires structural glass fins. A minimum processing fin depth of 200mm will be scheduled (normally about a 10th of the structural glass fin length). The o/all aesthetics of the structure should be reviewed on this basis. In addition normal ‘clear glass’ contains a natural green tint, which becomes more apparent through thicker glass (especially when looking directly onto the edge of the glass). On this basis the client may wish to consider a Low Iron glass to some components.
Unless a frameless glazed structure requires additional specialist finishing’s/coatings, there are no additional programme considerations with the frameless glazing system. Bespoke design programmes typically start at 10 weeks design and fabrication prior to site commencement (excluding approval periods).
Maintenance is often a poorly considered area, however represents a continuous cost consideration (cleaning, glass replacement etc.). It is important that all areas of maintenance are considered at length during the design process (a typical requirement under CDM regulations). Frameless Glazing designs normally contain large and heavy units, where expensive access and lifting equipment may be required during replacement/cleaning. Due to a glass structures design details; there may be a restricted range of suppliers from which the glass can be repurchased. As an ongoing cost, glass maintenance considerations should be paramount and should be reviewed during the planning process. When cleaning, frameless glazing systems have the added advantage of a flush external glass finish, resulting in no obstructions or advanced cleaning considerations. When exploring the utilisation of any glazing system and/or design, it is also worth requesting a budget cost for glass replacement so that the risk of breakage and associated cost can be considered.