Design Solution · Building Envelope
Design Solution · Dream about it
Retain the facade frame and replace only infill cassettes to cut embodied carbon.
Rather than stripping and replacing a whole unitised facade, the existing aluminium frame is retained and only infill cassettes (glazing, panels) are replaced. Because the retained material avoids new manufacture and transport, upfront embodied carbon (A1-A5) falls by roughly a quarter against full replacement, with further unaccounted savings in packaging, transport and construction waste.
Instead of stripping and replacing an entire unitised facade, this approach retains the existing aluminium frame and replaces only the infill cassettes — glazing units and spandrel panels — to achieve a performance upgrade at lower embodied-carbon cost than full replacement. The logic is sound: the aluminium frame, which carries significant embodied carbon from primary manufacture, is left in place; only the infill components that govern thermal and solar performance are renewed. A roughly 25% reduction in A1-A5 embodied carbon relative to full replacement is cited, and there are likely additional unquantified savings in packaging, transport, and construction waste. This record is at claimed status with no verified project evidence attached, so that figure requires scrutiny in the specific context. The potential value is compelling for deep-retrofit programmes where whole-life carbon is a target and the existing frame is in serviceable condition — the approach avoids the manufacturing, transport and waste footprint of new extrusions and reduces construction disruption compared with a full strip-out. The constraints are structural: the retained frame must be assessed for corrosion, thermal performance at mullion-transom junctions (which may still need thermal break upgrades), and compatibility with new cassette dimensions. If the existing frame geometry does not suit contemporary cassette products without modification, the embodied-carbon saving erodes. An early frame condition survey is a prerequisite, not a later-stage check.
#facade #retrofit #embodied carbon #reuse