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 framed curtain walling and patent glazing below.
Cost/Budget Considerations
Framed Glazing is one of the most cost effective traditional solutions available. Framed Glazing is typically 33% - 38% more cost effective than that of a Frameless Glazing equivalent and 15% - 20% more cost effective than Structural Glazing solutions.
Design Considerations
Framed glazing systems offer a less flexibility within design, however may be utilsed in most glass design applications. Should the glass design require windows or doors (typically framed), these items are typically developed and supplied as part of the standard system details. The glass units are provided with a black spacer and silicone seal as standard. It is however worth noting that the spacer colour should only be visible looking through the glass and that unless around a swimming pool, polysulphide sealed units may be utilsed. Float laminate glass specifications may also be utilised within curtain walling and patent glazing systems. Necessary glass engagements and clearances must be maintained to ensure no future disengagement or glass breakage due to expansion, contraction and movement. Framed glazing systems may also be provided in a modular arrangement for installation simplicity. In rooflight applications, the pitch and horizontal transom cap design should always be reviewed to ensure no associated water ponding.
As framed glazing systems do rely on weep water management (water entering the internal framework via the external caps/gaskets a minimum pitch of 15 degrees is required. The pressure plates and caps should also be machined to accommodate system pressure equalisation, which ensures the effectiveness of weep water system.
Aesthetical Considerations
In this instance, the size of the internal framework is purely determined by the structural requirements of the design (imposed loads). Many different system sections and caps may be utilised and should the contract value and programme permit, a bespoke/unique extrusion can be developed. The finish and framework positioning of this system is critical when reviewing its aesthetical implication and often a dual colour design may be adopted (differing colours internally and externally). Aluminium curtain walling and patent glazing systems may be anodised; however there will be some variation on finish between the framework and perimeter flashings. In addition no visible components may be welded.
Programme Considerations
Unless a framed glazed design requires additional specialist finishing’s/coatings, there are no additional programme considerations with the patent glazing and curtain walling systems. Bespoke design programmes typically start at 10 weeks design and fabrication prior to site commencement (excluding approval periods).
Maintenance Considerations
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). Framed Glazing designs may contain large and heavy units, where expensive access and lifting equipment may be required during replacement/cleaning. As an ongoing cost, glass maintenance considerations should be paramount and should be reviewed during the planning process. When cleaning, framed glazing systems have the disadvantage of proud caps/features, resulting in cleaning obstacles and ‘dirt traps’. 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. Generally, framed glazing systems are very easy to maintain and there are more contractors readily willing to undertake such works.
