Cities in the Netherlands are experimenting with a greener approach to urban roofs by using grass-filled paving blocks where traditional stamped concrete or asphalt might be used.
These specially designed blocks have open spaces where grass can grow, while gaps in the roof allow rainwater to pass through instead of flowing directly into drains. This approach can help reduce stormwater runoff during heavy rainfall and, depending on local soil conditions, allow water to infiltrate the ground or be temporarily stored below the surface. At the same time, introducing plants instead of completely enclosed roofs can contribute to creating cooler and greener urban environments during hot weather.
Why Dutch cities Solid concrete is replaced with grass-filled paving blocks
Traditional roads, parking lots and paved public spaces are largely impermeable, meaning rainwater cannot easily seep into the soil underneath. During heavy rainfall, large amounts of water can quickly flow into drains and sewer systems, increasing the risk of localized flooding when drainage capacity is exceeded.Grass-filled paving offers a different approach. Sometimes called turf pavers or open-cell concrete blocks, these surfaces have gaps in which plants can grow and rainwater can pass through.
Depending on the design and local soil conditions, water can seep into the ground, collect temporarily in subgrades or be released more slowly into drainage systems.The Netherlands has long placed water management at the heart of urban planning, and climate change adds new challenges. Heavy rains, periods of drought and increasingly hot weather are prompting cities to explore ways to make neighborhoods better equipped to handle extreme conditions.
Replacing unnecessary sealed surfaces with permeable alternatives is one tool available to urban planners.
Grass-filled paving can help cities manage heavy rainfall
One of the main advantages of permeable paving is its ability to manage rainwater close to where it falls. Traditional concrete and asphalt surfaces force water to flow across streets and sidewalks toward sewer systems. When exceptionally heavy rain falls in a short period, these systems can become overwhelmed.Permeable paving can slow this process by allowing some water to move across the surface. This can reduce the volume and speed of rainwater runoff entering the drains at one time. Under the right conditions, some water may also seep into the soil below.However, grass-filled paving does not guarantee that all rainwater will enter the groundwater immediately. Its effectiveness depends on soil permeability, groundwater levels, construction and maintenance methods.
Some systems are designed to temporarily store water below the surface before gradually releasing it.
Grass and plants can help reduce heat in urban areas
The potential benefits extend beyond rainfall. Concrete and asphalt can absorb solar energy during hot weather and release stored heat later, contributing to the urban heat island effect that can make densely built-up areas warmer than surrounding areas.Vegetation can contribute to local cooling through evapotranspiration, a process in which plants release water vapor into the atmosphere.
Replacing completely enclosed roofs with greener alternatives can therefore play a small role in creating more comfortable urban environments.The benefits of cooling should not be overstated. Grass-filled pavement alone cannot significantly lower temperatures for an entire city. Their contribution is most meaningful when combined with trees, gardens, green roofs and other forms of urban vegetation that provide additional shade and cooling.
Part of a broader green and blue shift
The grass-filled paving blocks are part of a broader approach often described as green and blue infrastructure. The concept involves integrating vegetation and water management into the design of streets, neighborhoods and public spaces.Instead of just treating stormwater as something that needs to be removed through underground pipes as quickly as possible, cities can create areas that absorb, slow or temporarily store water.
Measures could include permeable roofs, rain gardens, biolands, green roofs, ponds and specially designed public spaces capable of retaining excess rainwater.Dutch cities have explored different combinations of these measures according to local circumstances. Together, they can help reduce pressure on sewer systems while adding green space to dense neighborhoods.
Not every road can become a grass-covered street
Despite their environmental advantages, grass-filled paving blocks are not suitable for every site.
Roads with heavy, continuous traffic generally require durable surfaces capable of handling high loads and frequent wear. Grass may also struggle to survive as vehicles continually pass over the same sections.For this reason, grass pavers are generally most practical in select locations such as parking areas, residential lots, driveways, verges, and other relatively low-traffic surfaces.Maintenance is another important consideration. Holes in permeable paving can become clogged with sediment and debris, reducing the amount of water that can pass through. Vegetation also requires suitable growing conditions, while prolonged drought can affect grass and other plants.
A simple idea that has a broader role in climate-ready cities
Grass-filled paving is not exclusively Dutch, and permeable paving systems are used in many countries. What makes the Netherlands particularly important is its broader focus on integrating water management and climate adaptation into everyday urban planning.As cities around the world face heavy rainfall, flooding and rising temperatures, reducing unnecessary enclosed surfaces could become an increasingly important part of urban climate adaptation. Grass-filled paving blocks alone cannot solve the problem of flooding or heat stress, but they demonstrate how ordinary infrastructure can be designed to perform multiple functions.The deck can support vehicles or pedestrians while allowing water to pass through and creating space for plants. When combined with trees, parks, rain gardens, green roofs and efficient drainage systems, these approaches can help make cities more resilient to extreme weather while creating greener and potentially cooler neighborhoods.
