Sinkholes & Solution Features in Chalk
Sinkholes
Sinkholes appear where water flows through loose soil. This flowing water compacts the soils, creating a void. When these voids get big enough, the roof will eventually collapse resulting in a hole at the surface. Common causes include broken drains, guttering, and overflowing water butts.
These features are common in certain parts of Norfolk, including the Plumstead Road area of Norwich.
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Solution Features in Chalk
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Solution features are common in the chalk landscapes of East Anglia, particularly where shallow sandy soils are underlain by weak chalk.
Solution features occur where slightly acidic rainwater flows through and dissolves the chalk, creating a void. When these voids get big enough, the roof will eventually collapse resulting in a hole at the surface.
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Sinkhole Warning Signs
​Often, there are indications that a sinkhole may occur. The warning signs include;
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circular depressions that haven't always been there,
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trees of fence posts that lean,
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drain covers that stick up more than they used to,
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changes in drainage; puddles forming or draining away
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cracks in brick walls and concrete floors.
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​As part of our hazard identification process, we will assess the risk of these features and recommend action to avoid triggering them.
We can also investigate existing features and provide remedial advice and recommendations to existing features safe, identify the causes and prevent future incidence.
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