When Should I Worry About Cracks In Plaster?

Even though they are frequent in both older and younger homes, homeowners may find that cracks in the plaster cause them concern. Understanding when defects like hairline cracks or broader fissures are signs of settling or aging and when they can suggest more serious structural difficulties is crucial. Knowing what signs to look for and how to assess the problem’s severity is crucial.

This article will go over the different kinds of plaster cracks, their possible meanings, and the signs that it’s time to be concerned. Now that you know this, you can tell if the cracks are just for show or if there’s a more serious issue that needs a professional’s help.

When Should I Worry About Cracks In Plaster?

Cracks in plaster are a common occurrence in many homes, and while they often indicate minor issues, some cracks can be a sign of more significant structural problems. Knowing when to worry about cracks in plaster involves understanding the different types of cracks, their causes, and how they evolve. Here are some guidelines to help you determine when you should be concerned about cracks in plaster:

Size and Width of Cracks

  • Hairline Cracks: These are generally less than 1mm wide and are usually caused by natural settling or minor changes in temperature and humidity. They are typically not a cause for concern.
  • Wider Cracks: Cracks that are wider than 3mm may indicate more significant structural issues, especially if they continue to grow over time.

Direction and Pattern of Cracks

  • Horizontal Cracks: Cracks running horizontally can indicate pressure or tension from the load-bearing structure and may require professional assessment.
  • Vertical Cracks: While vertical cracks can be caused by settling, if they are wide or follow a consistent pattern, they may signal foundation issues.
  • Diagonal Cracks: These cracks are often associated with shifting foundations or structural movement, requiring immediate attention.

Location of Cracks

  • Around Doors and Windows: Cracks in these areas can be due to the settling of the house or improper installation. However, if these cracks widen or occur with other signs of structural damage, they should be investigated.
  • On Ceilings: Cracks on ceilings can indicate issues with roof structure or upper-level floors. If they grow or show signs of sagging, it’s crucial to seek professional advice.

Associated Signs

  • Water Damage: If cracks are accompanied by water stains, mould, or a musty smell, this could indicate a water leak or moisture problem.
  • Structural Movement: If doors and windows are misaligned, or you notice a sloping floor, these are signs of structural movement that need immediate attention.

Changes Over Time

  • Progressive Cracks: If cracks grow in length or width over time, it can be a sign of ongoing structural movement or settling.
  • Sudden Appearance of Cracks: If cracks appear suddenly or after a significant event (like an earthquake), they require prompt assessment.

Although not all cracks in plaster are cause for concern, it is crucial to keep a close check on their size, pattern, position, related indications, and how they evolve. Cracks in plaster can be used to identify potential problems. For a comprehensive assessment, it is important to get the advice of a structural engineer or a competent building inspector if you are unclear about anything or if you observe any symptoms that are cause for concern.

What To Do If Plaster Keeps Cracking?

If plaster in your home keeps cracking, it’s important to identify the underlying cause and take appropriate action to prevent further damage. Here are steps you can take to address recurring plaster cracks:

Identify the Cause

  • Structural Movement: Check for signs of structural issues, such as shifting foundations, sagging beams, or misaligned doors/windows. If you suspect a structural problem, consult a structural engineer for a thorough inspection.
  • Temperature and Humidity Changes: Fluctuations in temperature and humidity can cause plaster to expand and contract, leading to cracks. Consider using a dehumidifier or air conditioning to maintain consistent indoor conditions.
  • Poor Installation: If the plaster is not properly mixed or applied, it might be more prone to cracking. In this case, consult with a professional plasterer for an assessment.

Monitor the Cracks

  • Mark and Measure: Mark the edges of the cracks and measure their width and length. Keep track of changes over time to determine if they are growing.
  • Document Changes: Take photos of the cracks to document their progression. This information can be useful when consulting with professionals.

Repair the Cracks

  • Hairline Cracks: Small cracks can often be repaired with spackling paste or joint compound. Sand and paint over the repair for a smooth finish.
  • Larger Cracks: For wider cracks, use a plaster patching compound and apply mesh tape to reinforce the repair. Ensure proper drying and curing times before sanding and painting.
  • Consider Professional Repair: If the cracks are extensive or you lack experience, hire a professional plasterer to ensure a high-quality repair.

Address the Underlying Issue

  • Structural Repairs: If structural issues are identified, work with a structural engineer to address them. This may involve foundation repair, reinforcing beams, or addressing load-bearing walls.
  • Moisture Control: If moisture is causing the cracks, locate and fix leaks, improve drainage, or install a vapour barrier to prevent further damage.
  • Preventative Measures: Install expansion joints on large plaster surfaces to accommodate natural expansion and contraction. This can help prevent future cracks.

Regular Maintenance

  • Inspect Regularly: Periodically check for new cracks or changes in existing ones. Address them promptly to prevent further damage.
  • Maintain Consistent Conditions: Keep indoor temperatures and humidity levels consistent to minimize stress on plaster.

Cracks in plaster that keep appearing can be quite aggravating; but, if you properly diagnose and correct the problem, you can restore your walls and prevent more problems from occurring. If you are uncertain about the reason for the cracks or the severity of the cracks, the most effective course of action is to speak with professionals.


Plaster cracks are widespread and usually innocuous, but larger ones could indicate several significant structural issues that require repair. When determining whether or not a crack is structural, it is essential to take into consideration several crucial aspects, including its size, pattern, direction, position, accompanying signs and changes over time. In general, you should be concerned about cracks that are larger, diagonal, or horizontal, especially in foundation walls or adjacent to windows and doors.

Cracks have the potential to cause significant damage. Should you come across any other symptoms, such as doors that are unable to be opened, floors that slope, water seepage, or cracks that are developing, it is advisable to seek the guidance of an expert to conduct a comprehensive evaluation?

To ensure the security and stability of your house, it is important to address any potential structural issues before they become more severe. If you are doubtful of your capabilities, you may choose to seek the assistance of a structural engineer or a building inspector to establish the significance of a fracture. Regularly inspecting and maintaining your property allows you to identify potential issues earlier, have them repaired more quickly, and reduce the amount of stress you experience. In matters of structural integrity, it is preferable to take preventative measures and exercise caution to avoid the occurrence of problems that are more significant and costly in the future.

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