When choosing foam PVC thickness, most people ask a single question: "how strong should it be?" In practice three separate variables decide it — how the panel is mounted, how wide the unsupported span is, and whether the edge will be cut. Separate those three and the choice becomes obvious, and you stop paying for thickness you do not need.
Thickness by application
| Thickness | Typical job | Note |
|---|---|---|
| 3 mm | In-store graphics, short-run boards | Fine when framed or mounted flat |
| 5 mm | Wall-mounted signs, wayfinding | The most used thickness; will not bow over 1 m |
| 7 mm | Free-standing displays, shelf units | Extra stiffness without moving to composite |
| 10 mm | Dimensional letters, exhibition stands | Cuts cleanly on CNC without chipping |
| 15-19 mm | Structural pieces, display furniture | When the edge itself is part of the design |
1. Mounting method drives thickness
If the panel sits in a frame or is mounted flat to a surface, the substrate is not carrying the load and 3 mm foam PVC is plenty. If it hangs from two points, the load goes into the material itself and going below 5 mm is risky.
2. Unsupported span
Rule of thumb: past a 1 m unsupported span, do not go below 5 mm. Past 1.5 m you need 7 mm or a reinforcing frame. For genuinely large outdoor panels the right move is changing material rather than adding thickness — as covered in our substrate selection guide, this is where aluminium composite takes over.
3. Is it being cut?
With contour cutting or dimensional letters, thickness becomes an aesthetic decision: the cut edge is now a visible surface. 10 mm foam PVC gives letters shadow and depth. 19 mm is for pieces that must stand on their own. Remember to supply the cut path with your artwork — details in our file preparation guide.
What extra thickness does not fix
A common mistake is choosing thick foam PVC for outdoor durability. Foam PVC's outdoor problem is not rigidity but UV yellowing and embrittlement. A 19 mm sheet yellows exactly like a 3 mm one. Outdoors, solve it with material, not thickness.
Frequently asked questions
Are Dekota and Forex the same thing?
Yes. Both are brand names for expanded closed-cell PVC sheet.
Can I bond two 3 mm sheets instead of using 5 mm?
Technically possible but not advised: the bond line separates over time and shows as a line on any cut edge.
At what thickness does weight become an issue?
Above 10 mm, factor in the mounting hardware. Foam PVC is light, but at 19 mm and large formats double-sided tape alone will not hold.
