How to Fix a Poster That Won't Stay Flat on the Wall

Quick Answer

To fix a poster that won't stay flat, first diagnose the cause—humidity, poor adhesive, or storage curl—then apply a targeted solution like weight, gentle heat, or a better mounting method.

Diagnose & Fix Your Poster

• Symptom: Edges curl upward or inward after hanging, or the poster won't lie flat against the wall.
• Likely Cause: Humidity change, poor adhesive (tape or putty not holding), or the poster was stored rolled for weeks.
• Corrective Action: For mild curl: lay the poster face-down on a clean surface, place heavy books on the corners for 24 hours. For stubborn curl: gently iron the back on low heat (no steam) through a thin cloth, then re-roll in the opposite direction for a few hours. For hanging: use poster mounting strips on all four corners and mid-edges, or frame the poster behind glass. If the poster still won't lie flat after these steps, the paper has taken a permanent set.
• Stop or Choose Another Option: Stop trying to flatten a poster with deep creases or torn edges—it will never look right. Instead, replace it with a poster printed on thicker paper or one with a bold graphic design that makes minor waves less visible. A new poster like the '6.4.2 Wow' typography print can refresh your wall with a design that stays visually clean even if the paper isn't perfectly flat.

A Poster That Stays Flat by Design

• 6.4.2 Wow: Poster with graphic typography featuring the word 'Wow,' made in green and pink RAL-colours. Bold, high-contrast typography draws the eye to the message, so any slight curling becomes less noticeable than it would be on a photographic print.