An aluminium curtain wall is a non-structural building envelope hung off the floor slabs, made of aluminium framing infilled with glass and panels. The two systems are stick (assembled piece by piece on site) and unitised (pre-built panels craned into place). ACP and solid aluminium panels are the opaque infill within that frame. If you fabricate facades, you buy the aluminium extrusions, the coil/sheet and the ACP as inputs — this explains where each goes.
Stick vs unitised — the core choice
Stick systems ship as extrusions and glass and are built on the facade piece by piece — flexible, lower tooling cost, slower on site, best for low-rise and irregular shapes. Unitised systems are assembled into storey-height panels in a factory and craned onto the building — faster, higher quality control, best for high-rise, but needs more up-front engineering.
Where ACP and solid aluminium fit
Curtain wall is mostly glass, but the opaque zones (spandrels, columns, feature bands) are infilled with panels: FR ACP for value, solid aluminium for non-combustible or prestige facades. So a facade contractor buys glass, aluminium framing extrusions, and ACP/solid-aluminium infill — often from different suppliers.
What a facade buyer sources from a factory
From a metal factory you typically buy: PVDF aluminium coil and sheet (for cassettes, flashings, trims), FR ACP (for infill and rainscreen), and sometimes aluminium profiles. Getting coil and ACP colour-matched from one source keeps the facade consistent — worth asking for when the spandrel ACP and the metal trims must read as one colour.
Fire and the modern curtain wall
Since Grenfell, the opaque infill and any rainscreen on a curtain wall face fire scrutiny. Gulf, UK and EU codes push FR or A2 cores on tall buildings. Specify the fire class for the panel infill, not just the glass, and keep the EN 13501 certificate for the exact ACP or aluminium used.
Frequently asked questions
What is a curtain wall? A non-structural aluminium-framed building envelope, hung off the floor slabs, infilled with glass and panels.
What is the difference between stick and unitised? Stick is assembled piece by piece on site; unitised is pre-built into storey-height panels and craned on — faster and higher QC.
Where does ACP go in a curtain wall? In the opaque zones — spandrels, columns, feature bands — as infill, usually FR-core for facades.
What do facade fabricators buy from a metal factory? PVDF aluminium coil and sheet, FR ACP, and sometimes aluminium profiles — ideally colour-matched from one source.
Related: ACP vs solid aluminium vs insulated panel · ACP buyer’s guide · PVDF aluminium coil sourcing.
Talk to the factory: GSM BuildTech (Beijing Guanshimao Technology Co., Ltd.) makes insulated aluminium panels, FR aluminium composite panels, standing-seam aluminium roofing and PVDF aluminium coil in Tianjin, China. Email sales@insulatedaluminumroof.com or WhatsApp +86 155 2274 6824 for factory-direct pricing. See the technical reference & FAQ.