Structural issues in a home don’t usually appear all at once. They develop gradually — through movement in the ground, moisture changes, aging materials, or improper construction. The key is recognising early warning signs before they turn into expensive repairs.
Most homeowners aren’t trained to identify structural movement — and that’s normal. But there are clear patterns and visible clues that can help you know when something is minor cosmetic settling and when it needs professional inspection.
This guide explains how to tell if a home may have structural issues, what the warning signs look like, what causes them, and when to take action.
Snapshot Summary (Quick Overview)
| Sign | What It May Mean | Next Step |
|---|---|---|
| Cracks wider than 5mm | Structural movement, not paint shrinkage | Get inspected |
| Doors & windows sticking suddenly | Frame movement or slab shift | Monitor + review |
| Sloping or uneven floors | Foundation or stump issues | Professional assessment |
| Gaps opening around skirting or ceilings | House movement or timber shrinkage | Inspect moisture & subfloor |
| Water pooling or damp smells | Moisture affecting structural timber | Fix drainage & assess damage |
Not all cracks are structural.
Not all movement is dangerous.
The goal is to identify the difference.
1. Cracks in Walls: Cosmetic vs Structural
Cracks are the most common sign homeowners notice.
Not all cracks indicate a serious issue.
Cosmetic Cracks (Usually Harmless):
- Hairline cracks (<1mm)
- Located only in paint or plaster layer
- Appear around new renovations or seasonal changes
Common causes: humidity, surface shrinkage, minor settlement.
Structural Movement Cracks (Needs Assessment):
Look for:
| Crack Type | What to Watch For |
|---|---|
| Wider than 5mm | Indicates building movement |
| Diagonal cracks from corners of doors/windows | Frame has shifted |
| Stepped cracks in brickwork | Foundation movement or soil reactivity |
| Cracks that increase over weeks | Active movement |
Did You Know?
Australian soil is some of the most reactive in the world, especially in VIC, SA, and parts of QLD — meaning foundations expand and contract with moisture changes (CSIRO).
Pro Tip:
Take a photo with a date. If the crack changes → movement is active → get inspected.
2. Doors & Windows That Stick or Don’t Close Smoothly
If doors or windows:
- Suddenly jam
- Won’t latch
- Have gaps that were not there before
This often indicates movement in the frame, which can be caused by:
- Foundation settling
- Moisture changes in timber framing
- Subfloor ventilation issues
Rule of Thumb
If one door sticks → may be swelling or humidity.
If multiple doors/windows change → investigate structural movement.
3. Sloping or Uneven Floors
Floors should feel level.
If you:
- Feel lean when walking
- Notice objects rolling on their own
- See visible slope across a room
This can signal:
- Foundation sinking
- Stump failure (common in timber homes)
- Concrete slab heave (common on reactive clay soils)
Quick Test:
Place a small ball on the floor.
If it rolls with momentum → this is measurable slope → seek inspection.
4. Moisture, Dampness & Mould: The Hidden Structural Enemy
Moisture is the #1 cause of long-term structural damage in Australian homes. It weakens timber and causes movement in slabs and footings.
Look for:
- Damp smells in rooms or wardrobes
- Mould on walls or skirting boards
- Water pooling around the home’s perimeter
- Peeling paint or bubbling plaster
Cause: Poor drainage, leaking plumbing, or inadequate subfloor ventilation.
Action: Fix moisture source first — then inspect structure.
5. External Brickwork & Retaining Walls
Outside signs are just as important.
Warning Signs Outside
- Stepped cracks in brick mortar
- Bulging brickwork
- Retaining walls leaning forward
- Gaps between brickwork and windows
These often indicate soil movement or poor drainage, especially after heavy rain.
6. Rooflines and Sagging Ceilings
Look at the roof profile from the street.
Indicators of Structural Stress:
- Roofline sags, dips, or waves
- Internal ceilings show cracks or sagging
- Cornices separating from walls
This can signal:
- Truss or rafter movement
- Load-bearing wall compromise
- Water damage weakening roof timbers
This requires professional assessment immediately.
Quick Guide: What To Do If You Notice These Signs
Do This First
- Photograph the issue
- Date-stamp and monitor changes
- Reduce moisture sources where possible
Then
| Situation | Action |
|---|---|
| Minor, stable cracks | Monitor every 30 days |
| Cracks growing or multiple areas affected | Call a building inspector |
| Visible floor movement or roof sagging | Immediate professional assessment |
Never:
Try to fix structural cracks with filler or plaster — that just hides the symptom, not the cause.
Homeowner Self-Assessment Quiz
| Question | Yes | No |
|---|---|---|
| Have cracks widened over time? | ||
| Are multiple doors or windows sticking? | ||
| Do floors feel uneven or sloped? | ||
| Is there mould, damp, or a musty smell? | ||
| Has water pooled around your home after rain? |
If you answered “Yes” to 2+ items → an inspection is recommended.
FAQs
Q: Should I panic if I see cracks?
No. Cracks are common — focus on change over time, not appearance alone.
Q: Who inspects structural issues?
A licensed building inspector or structural engineer, depending on severity.
Q: Will insurance cover structural repairs?
Usually not, unless caused by an insurable event (e.g., storm, impact).
Q: Can I still buy a house showing these signs?
Yes — but only after a thorough pre-purchase structural inspection.
Conclusion
Structural issues don’t appear suddenly — they develop gradually. The key is recognising pattern, movement, and moisture early. Not every crack or slope is serious, but the signs listed in this guide tell you when to watch and when to act. Monitoring, documenting, and getting a professional assessment before problems escalate can save thousands in long-term repairs. Homes are designed to move — but when movement becomes visible, progressive, or widespread, it’s time to take it seriously. The earlier you intervene, the simpler (and cheaper) the solution will be.
Disclaimer
This article provides general building information only. It is not a substitute for a professional structural inspection or engineering assessment.
