Choosing between stick and unitised curtain walling involves more than comparing a square-metre rate. The decision affects when the design must be resolved, where assembly takes place, how components reach the building and how the finished façade is inspected and maintained.
Both approaches can deliver successful façades. Their suitability depends on the particular system and the conditions under which it will be designed, manufactured and installed.
Understand where the work happens
In stick construction, framing members are generally assembled on the building and the glazing or opaque infill installed on site. In unitised construction, substantial assemblies are prepared before delivery and installed as units. Real projects may combine these approaches.
Factory assembly can provide controlled conditions for some operations, but it does not remove site dependencies. Unit-to-unit joints, support brackets, perimeter connections and installation tolerances remain important. Conversely, site assembly needs a practical plan for access, protection and quality control throughout the work.
Assess repetition and geometry
Repeated bays can support efficient unit production. Frequent changes in geometry, dimensions or interfaces may require many different unit types. That affects drawings, production control, packing and installation order.
Stick systems may offer useful flexibility for some layouts, but flexibility has limits. A modified proprietary system still needs evidence that its structural, drainage, sealing and thermal behaviour suit the proposed arrangement. Familiar profiles do not make every new configuration equivalent to one already tested.
Compare the whole programme
A unitised approach may reduce certain site assembly activities while increasing the importance of early coordination and manufacturing release. A drawing change issued after production begins can affect components already fabricated or packed for delivery.
For stick construction, assess the sequence of framing, glazing, sealing and finishing. Confirm how often the installation team needs access to each area and when internal works can proceed.
Compare realistic programmes that include design development, procurement, testing, production, transport and erection. A fast installation rate is only useful if the necessary units and lifting resources arrive in the correct sequence.
Plan the journey from factory to final position
For a constrained site, ask where deliveries can stop, how panels are offloaded and what happens when wind or crane availability interrupts installation. Storage and temporary loads require coordination. Installed work also needs protection from later activities.
For site-assembled systems, consider how profiles and glass are stored, handled and brought to the workface. Repeated handling and limited working space can influence damage, productivity and inspection quality.
Make quality requirements specific
The inspection plan should reflect the construction method. Factory checks may include assembly dimensions and completed seals. Site checks may include bracket positions, joint engagement, gasket continuity and interfaces before concealment.
Neither method should be selected on an assumption that quality is automatic. Specify what will be checked, who records it and what happens when a condition falls outside the accepted limits. Agree how representative test evidence relates to the actual project configuration.
Consider replacement before the building opens
Ask how a damaged glazing unit or façade component will be replaced. The answer depends on the system, access and connections. Review whether removal can occur from inside or outside, what lifting arrangement is required and how adjacent seals will be reinstated.
A sensible selection records the reasons for the chosen approach against project priorities. Cost, programme and appearance belong in that record alongside movement, weather resistance, logistics and maintenance. This gives later design changes a clear basis for review.
Further reading
CWCT: Specification provides a framework for defining project performance. Selection should also use the proposed system supplier’s drawings, installation instructions and applicable test evidence.
General educational guidance. Apply current requirements, the selected system’s evidence and project-specific professional assessment to design and construction decisions.