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Crazing and cracks on roof

Short answer

Crazing is a network of fine, shallow surface cracks caused by rapid drying, rich mix, or over-trowelling. Common roof crack problems include thermal expansion and contraction of slab and parapet, shrinkage from poor curing, deflection, reinforcement corrosion, differential movement, and lack of expansion joints or waterproofing.

Define crazing. What are the common problems for crack on roof of the building?

Crazing

Crazing is the formation of a network of fine, shallow, hair-like cracks on the surface of plaster, concrete, paint or glaze, looking like a spider web or map. It is caused by shrinkage of the surface layer due to rapid drying, rich mix, too much trowelling, or sudden temperature change. It affects appearance only and is repaired by filling with cement slurry or repainting.

Common problems of cracks on roofs

  • Thermal expansion and contraction of a slab or parapet in sun, causing cracks and leaks.
  • Shrinkage cracks in the terrace screed or slab due to poor curing.
  • Deflection and overload causing cracks in slabs.
  • Corrosion of reinforcement with spalling at the soffit.
  • Differential movement of the parapet and slab causing horizontal cracks.
  • Poor waterproofing and ponding, giving leakage and dampness.
  • Lack of expansion joints in large terraces.

Prevention: good curing, expansion joints, insulation and waterproofing, correct slope, proper reinforcement cover.

✓ Answer checked by Claude Opus 5.5 (high effort)

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