Patched Wall Cracks
Previously cracked walls that have been patched or filled indicate prior ground movement or settlement. While the cosmetic repair may look sound at the time of inspection, the underlying cause - reactive soil movement, differential settlement, or footing inadequacy - may not have been addressed. Patched cracks that re-open signal ongoing movement and warrant structural assessment under AS 2870.
Severity rationale
This is the third most frequent defect in the corpus at 12.35% of all reports, with 959 observations. The modal score is 2, recorded in 618 cases (64.4%), and scores of 1 account for 20 findings (2.1%). The average of 2.32 confirms the defect is overwhelmingly low-to-moderate in severity. Only 5 observations (0.5%) reached 4 or 5, indicating that active re-opening with structural implications is rare. The score rises when cracks have visibly re-opened through the patch, when door frames are binding, or when the patch pattern aligns with a known reactive soil settlement trajectory.
Causes
- Prior ground settlement or differential footing movement that cracked the internal wall
- Reactive soil expansion and contraction causing repeated seasonal wall movement
- Cosmetic patching carried out without investigating or rectifying the root cause
- Normal post-construction material drying and shrinkage that was later filled
- Previous moisture ingress that softened plaster or render, leading to cracking
Symptoms to look for
- Visible filled or skim-coated areas on internal walls where cracks previously ran
- Paint texture or sheen difference between patched areas and surrounding wall
- Re-opened cracks through or adjacent to previous patch repairs
- Discolouration or staining around patched zones suggesting prior moisture involvement
- Multiple patches distributed along the same wall, indicating a recurring crack pattern
Remedies
- Monitor patched areas over at least one full seasonal cycle to determine whether cracks re-open
- If cracks re-open, engage a structural engineer to assess the footing system and determine whether rectification is required under AS 2870
- Engage a plasterer to re-patch and finish once movement has stabilised
- Improve site drainage and remove vegetation near footings if reactive soil movement is suspected as a contributing factor
Where we see this most
These suburbs show the highest concentration of patched wall cracks in our inspection data (minimum five observations). Click a suburb to see its full defect profile.
Worth asking our inspector about this specifically.
Patched wall cracks alone are not a reason to walk away from a purchase, but they are a signal to watch. If cracks re-open in the first wet season after purchase, commission a structural engineer assessment before undertaking further cosmetic repairs.