Corflute, ACM, foamex, foamboard, acrylic, aluminium and banner PVC, explained by the people who print on all of them. What each one is, how long it lasts outside, and the honest answer to which one your job needs.
For a temporary outdoor sign, use corflute. It is the cheapest rigid board that survives outside, for about six to eighteen months. For a permanent outdoor sign, use ACM, which commonly lasts seven to ten years on a wall. Indoors, foamex is the workhorse and acrylic is the premium option. For big flexible signs, use banner PVC, or mesh wherever wind is involved.
Written by Melbourne Trade Signs, a large-format print and signage company at Unit 6/43 Orbis Drive, Ravenhall VIC 3023. We print and install signage for builders and businesses across Melbourne. Updated October 2026.
| Material | What it is | Outdoor life (Melbourne) | Best for | Avoid for |
|---|---|---|---|---|
| Corflute | Fluted polypropylene board, 2–5 mm | About 6–18 months | Site signs, real estate, events, short campaigns | Anything that has to look sharp for years |
| ACM | Aluminium skins on a plastic core, usually 3 mm | Commonly 7–10 years on a wall | Shopfronts, fascias, permanent site and safety signs | Short jobs where it will be thrown away |
| Foamex (PVC) | Expanded PVC foam sheet, 1–19 mm | Several years only if sheltered and laminated | Indoor wall, door and retail signs | Exposed outdoor walls |
| Foamboard | Polystyrene foam between paper or plastic faces | A season at most | Displays, events, presentations, POS | Outdoors, humidity, anything handled a lot |
| Acrylic | Cast or extruded acrylic sheet, 3–10 mm | Good, does not yellow like polycarbonate | Reception signs, plaques, premium panels | High-traffic spots where scratches show |
| Aluminium | Solid aluminium sheet | Many years, and survives knocks | Post-mounted, traffic, reflective and gate signs | Large lightweight panels |
| Banner PVC | Coated woven polyester, typically 440 gsm | About 2–3 years at standard weight | Large outdoor messages on walls and hoarding | Open temporary fencing (use mesh) |
| Mesh | Perforated banner PVC, 270–340 gsm | About 2–3 years | Fences, scaffold, anything exposed to wind | Close-up photographic detail |
The outdoor lifespans are honest ranges for Melbourne conditions, not guarantees. Sun exposure decides where a sign lands inside the range: a north-facing sign on an open site ages far faster than the same sign under an awning or on a south wall.
Corflute is fluted polypropylene board: two thin plastic skins with hollow ribs, or flutes, running between them. It behaves like plastic cardboard. It is very light, completely waterproof, and cheap enough to treat as temporary. In Australia “corflute” is the everyday name for it. Elsewhere you will see corrugated plastic, fluted plastic board or Coroplast.
For signs it is usually printed on 3 mm board (up to about 900 × 1200 mm fixed flat) or 5 mm board (larger panels, temporary fencing, and boards that get handled every week). It comes in 2400 × 1200 mm sheets and cuts to any shape.
Water does not hurt it. What ages corflute is sunlight and handling: the plastic goes chalky, reds fade first, cut edges scuff and flutes crush underfoot. Six to eighteen months outdoors is the realistic range. It is polypropylene, resin code 5, so it is technically recyclable, though kerbside acceptance varies between councils.
Use it for site signs, real estate boards, election and event signage, and short promotional runs: anything you expect to replace. Do not use it for a shopfront you want to look sharp in three years. Full specs are on our corflute signs page.
ACM stands for aluminium composite material. It is two thin aluminium skins bonded to a plastic core, usually 3 mm thick overall. You will also see it called ACP (aluminium composite panel), or by brand names like Alupanel, Dibond and Alucobond. For signage they all mean the same type of product.
It stays dead flat, does not rust, takes screws and rivets, and can be routed into shapes or folded into trays with hidden edges. On a wall in Melbourne, seven to ten years is a fair expectation, and the print usually gives up before the panel does. That makes it the default for shopfronts, fascias, permanent safety and parking signs, and site boards on long builds.
One caution: standard signage ACM has a polyethylene core, which is combustible. Mineral-core panels exist for facade work. Whether a sign on a building needs them depends on the building class, the height and what the building surveyor requires, so raise it at quoting stage. More on our ACM signs page.
A closed-cell PVC sheet with a fine foam core and smooth faces, from 1 mm to 19 mm. 3 mm is the everyday indoor wall and door sign, and 10 mm and up is used for cut lettering. Indoors it is the best-value rigid sign there is. Outside, it only works under a verandah or on a shaded wall, laminated. Foamex signs.
Polystyrene foam sandwiched between paper or thin plastic faces. Very light and very cheap, and it makes a crisp display panel, menu board or event sign. It is an indoor, short-life product that dents easily, and outdoors it is finished in a season. Foamboard printing.
The premium indoor option: reception logos, plaques, and panels on standoffs. 5 mm is the workhorse thickness. Cast acrylic handles the outdoors better than most plastics and does not yellow the way polycarbonate does. It does scratch more easily than glass, and it expands and contracts with temperature, so outdoor panels need oversized fixing holes. Acrylic signs.
Solid sheet rather than a composite. It is heavier, and it takes a knock from a forklift or a car door without folding, which is why it is used for post-mounted, gate and traffic signs and as the base for reflective signage.
Flexible rather than rigid. Standard banner PVC is about 440 gsm coated polyester and lasts about two to three years outdoors. Mesh is perforated so wind passes through it, which is the only safe choice on freestanding temporary fencing: a solid banner turns a fence panel into a sail. Vinyl banners and mesh banners.
| Corflute | ACM | |
|---|---|---|
| Construction | Fluted polypropylene | Aluminium skins on a plastic core |
| Outdoor life | About 6–18 months | Commonly 7–10 years |
| Up-front cost | Lowest of any rigid board | Several times corflute |
| Rigidity | Flexes on large panels | Dead flat, can be folded into trays |
| Weight | Very light, cable-ties to fences | Heavier, screws or rivets |
| Best for | Temporary site, real estate and event signs | Shopfronts, permanent signs, long builds |
The deciding question is how long the sign needs to last. Under a year, corflute nearly always wins. Over two or three years, ACM is usually cheaper over its life, because corflute would be replaced several times. On long construction projects we often recommend both: a permanent ACM entry board, with corflute for the messages that change week to week.
If you are still not sure, tell us where the sign goes and how long it has to last, and we will tell you which material we would use and why. Sometimes that is the cheaper option.
Corflute is fluted polypropylene: two thin plastic skins joined by hollow ribs called flutes. It is light, rigid for its weight and waterproof. In Australia it is the standard board for temporary outdoor signs, and it is usually printed on 3 mm or 5 mm stock.
Yes. Polypropylene does not absorb water, swell or delaminate, so rain does not damage a corflute sign. What ages it outdoors is UV light and handling. The plastic slowly goes chalky and the colours fade, with reds going first.
About six to eighteen months in Melbourne, depending on sun exposure. A board on a shaded or south-facing fence lasts toward the top of that range, while a north-facing board on an open site can look tired in under a year. For three years or more, use ACM.
ACM is aluminium composite material: two thin aluminium skins bonded to a plastic core, usually 3 mm thick. It is also called ACP, Alupanel, Dibond or Alucobond. It is the standard material for permanent outdoor signs because it stays flat, does not rust and commonly lasts seven to ten years on a wall.
Use corflute if the sign is needed for less than about a year or is likely to be damaged and replaced. Use ACM for a build running longer than a year, a permanently mounted entry board, or anywhere a warped or faded board would reflect badly on the project. Many builders use both.
For printed signs, ACM and solid aluminium last the longest, commonly seven to ten years or more. Aluminium is the tougher of the two against knocks. In practice the print or vinyl on the face ages before either panel fails.
Only somewhere sheltered. Under a verandah or on a shaded wall, a laminated 5 mm foamex panel gives several years of useful life. On an exposed wall in full sun, use ACM instead.
Standard sizes in millimetres for banners, corflute, pull-ups, A-frames, real estate and safety signs.
Read the guide →Corflute signs printed and cut in Ravenhall on 3 mm or 5 mm board, with no minimum order.
See corflute →Aluminium composite panels for shopfronts, fascias and permanent outdoor signs.
See ACM →Send the size, where it goes and how long it needs to last. We will tell you which material we would use, and price it inside two business hours.