Unsealing the City: Planting vs. Paving Urban Spaces

What unsustainable behaviour needs to change:

From concrete tiles in front gardens to sealed sidewalks and patios, many cities are suffocating under impermeable surfaces. This excessive “urban sealing” blocks rainwater, overheats neighbourhoods, and erases space for biodiversity. In the Netherlands, paved private gardens alone account for over 60% of the country’s residential outdoor area, contributing significantly to local flooding and heat stress.

Still, residents often don’t realise their own driveway or back patio plays a role. It’s a classic case of ‘diffusion of responsibility’ and ‘status quo bias’—“everyone does it” and “it’s always been there.” The default is inaction.

But what if removing pavement felt like a point of pride—not a chore?

The Green Nudge:

Since 2020, the Netherlands has hosted NK Tegelwippen, the National Tile-Flipping Championship. From March to October each year, Dutch cities compete to see who can unseal the most surface area—not just tiles, but all kinds of concrete pavement.

Residents pull up slabs, bricks or tiles and register their removals online. Each city’s tally is updated live on a national leaderboard. In 2023, Arnhem led the way, removing over 460,000 tiles, while the national count surpassed 5 million since the contest began.

So why does this work so well?

• Gamification
  – Turning a sustainability task into a game adds urgency, clarity, and fun.
  – People can track progress in real-time, earn virtual recognition, and feel rewarded for each square metre unsealed.
• Social Comparison
  – Public leaderboards show which city—or neighbour—is pulling ahead, triggering friendly competition.
  – Visibility normalises the behaviour: “If others are doing it, I can too.”
• Local Pride
  – Cities and districts build identity through participation (“We’re not just greener—we’re winning!”).
  – Municipalities often highlight local champions or give small incentives (e.g. free plants or compost).

By celebrating each removed tile as part of a bigger collective win, NK Tegelwippen transforms unsealing into a shared achievement—not an isolated effort.

And it’s easy to replicate: whether in neighbourhoods, schools or housing co-ops, the magic lies in giving people permission, visibility, and momentum to rip up what’s no longer serving them—or the climate.

Do you know clever nudges that help cities stay cooler and manage water better?
Feel free to comment or get in touch: hello@green-nudges.com

From the Green Nudges Consulting team—behavioural science consultants on a mission not just to shuffle the chairs on the Titanic, but to drive real change that makes a measurable difference. We’re always inspired by bold, practical approaches that create impact at scale.