What is petrification?
Petrification literally means turning into stone or covering with stone. In Dutch it is called verstenen, and in construction and spatial planning the Dutch word is used in three meanings.
1. Hardening into stone
A material that changes into a hard, stony substance. This can happen quickly, such as fresh concrete hardening into concrete or clay becoming brick when fired. It can also be a geological process lasting millions of years: clay becomes claystone and shale, sand becomes sandstone, and wood can fossilise into petrified wood.
2. Replacing timber facades with stone facades
In medieval towns, many houses were made of timber. After major town fires, from the late Middle Ages onwards, towns switched to stone facades, often of brick. This is called the petrification of the town. In some old buildings in Dutch town centres, a timber load-bearing structure still sits behind a stone front facade.
3. Building over or paving green space
Today, the Dutch word is mainly used for the disappearance of greenery: meadows that become housing estates, parks that make way for buildings and gardens that are paved over. Consequences of this in towns include:
- Rainwater cannot soak into the ground and puts pressure on the sewer, with a risk of flooding in heavy downpours.
- Stone and paving slabs heat up and retain heat, making the town warmer.
- Less room for plants, insects and birds.
Tips to depave your own plot
- Replace paving with planting or use grass pavers or open paving where you need to walk or park.
- Disconnect the downpipe and route it to a water butt, infiltration crate or swale, if the soil and the municipality allow it. Ask your municipality which rules apply to disconnecting.
- Facade garden or green roof: even on a small area, greenery helps retain water.
- Look for subsidies: in the Netherlands, many municipalities and water boards have schemes for disconnecting downpipes or greening. The conditions differ per municipality, so always check the current scheme.
Related terms
- Facade garden
- Green roof
- Infiltration in your own garden
- Climate-adaptive
- Sedimentary rock
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