Why Does My Coving Keep Cracking? Causes & Fixes

Cracked plaster coving repair in Victorian London home

Quick Summary:


Cracks in coving are usually caused by structural movement, temperature changes, or poor installation. This guide explains the main reasons coving cracks, how to tell if it’s cosmetic or serious, and the best repair solutions for lasting results.

 

Common Causes of Cracks in Coving

 

1. Building Movement

 

  • Houses naturally shift over time, especially older properties.

  • Seasonal expansion and contraction of walls and ceilings can cause cracks at the joints.

 

2. Poor Installation or Adhesive Failure

 

  • If cheap fillers or weak adhesives were used, coving may detach or crack as the bond fails.

  • Gaps can appear where coving meets the wall or ceiling.

 

3. Temperature & Humidity Fluctuations

 

  • Central heating, damp, or poor ventilation can cause plaster to expand and contract.

  • This stresses the coving, leading to hairline cracks.

 

4. Water Damage

 

  • Leaks from pipes or roofs weaken plaster.

  • Once dry, the coving may shrink and crack further.

 

5. Structural Issues

 

  • Large diagonal cracks could indicate subsidence or major structural movement.

  • These require a professional survey before repair.

 

How to Fix Cracked Coving

 

For Small Hairline Cracks

 

  • Gently widen with a scraper.

  • Apply fine filler suitable for plaster mouldings.

  • Sand smooth and repaint.

 

For Gaps at Joints or Between Wall & Ceiling

 

  • Remove loose material.

  • Re-adhere with strong plaster adhesive.

  • Finish with fine filler and paint.

 

For Larger Breaks or Missing Sections

 

  • Take a mould of the existing coving pattern.

  • Cast a replacement section in lime/gypsum plaster.

  • Install and blend seamlessly with the original.

 

For Ongoing or Severe Cracks

 

 

Preventing Future Cracks in Coving

 

  • Maintain consistent indoor humidity.

  • Repair leaks promptly.

  • Use traditional plaster, not cheap lightweight alternatives, for longevity.

  • Choose experienced specialists for installation or repair.

 

Frequently Asked Questions

 

Are cracks in coving normal?

Yes — hairline cracks are common, especially in older homes, and are often cosmetic.

Can cracked coving be repaired without replacement?

Yes. Minor cracks can be filled. Severe damage may need new sections cast to match.

How much does coving crack repair cost?

Small crack repairs may be under £150, while casting and fitting new sections can cost several hundred pounds depending on complexity.

Is cracked coving a sign of structural problems?

Small cracks usually aren’t. Large or recurring cracks may indicate movement and should be checked.

 

About Cornice Cleaning Ltd

 

At Cornice Cleaning Ltd, we’ve been repairing and restoring coving and cornices across London since 1983. Using traditional lime and gypsum plaster, we restore even badly cracked or damaged mouldings so they look original once again.

📍 Based in London — covering North & East London
📞 Call us today for a free quote: 07956 332144