Application
Why plaster cracks — and how to prevent it
Four common causes of cracking in plasterwork, and what to do at each stage.
August 12, 2026 · 5 min read
Coats that are too thick
Each product is designed for a thickness range: base coat up to 25 mm per coat, finish up to 3 mm. Beyond that, shrinkage while drying causes cracks.
An over-dry base
If the base coat pulls water out of the finish too quickly, the finish never sets fully. Dampen the base slightly before finishing.
Draughts and heat
Open windows on a hot day dry the surface before it sets. Keep draughts out until final set.
Too much water
More water than the recommended ratio makes plaster easier to spread but weaker. The water ratio is on every product's data sheet.
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