In Wagga Wagga, reactive shrink-swell clay moves under homes every single year. The question is whether that movement is within expected limits or has become cumulative, progressive damage that needs professional attention. Most homeowners notice the signs but are not sure what to make of them.
This guide is the definitive local checklist. Go through it systematically for your home. The more signs you recognise, particularly from the “act now” category, the more urgently you need a professional foundation inspection.
Category 1: External Signs
Walk around the outside of your home and look for:
1.1 Diagonal Cracks in Brickwork
What it looks like: Cracks that run diagonally across brick courses or, more commonly, step diagonally along mortar joints.
Where to look: The corners of the building, around window and door openings, where the verandah meets the main house.
Urgency level by width:
- Hairline (less than 0.5 mm): Monitor
- Fine (0.5-2 mm): Inspect within 6 months
- Medium (2-5 mm): Inspect within 2 months
- Wide (5-15 mm): Inspect urgently
- Very wide (15 mm+): Get emergency assessment
Context in Wagga: This is the most common and most diagnostic external sign in brick veneer and double-brick homes across Kooringal, Ashmont, Lake Albert, and Tolland.
1.2 Stepped Cracks Following Mortar Joints
What it looks like: A staircase pattern of cracks following horizontal mortar beds and vertical perpends alternately.
Where to look: Anywhere in the external brickwork, especially at corners.
Urgency: Any stepped crack in external brickwork wider than 2 mm warrants inspection.
1.3 Visible Gap Between Slab Edge and Wall
What it looks like: Looking at the base of an external wall, there is a visible gap or lip between the bottom of the brick course and the top of the concrete slab. The slab has dropped.
Where to look: All external walls at ground level. Easier to see after heavy rain when the gap may be visible contrast in the wet surface.
Urgency: Any visible gap indicates slab edge settlement. Inspect within 3 months.
1.4 Verandah Separating from Main House
What it looks like: A gap opening between the verandah roof and the main house wall, or between the verandah floor and the main house structure.
Where to look: The junction between the verandah and the house at both roof and floor level.
Urgency: A gap wider than 10 mm, or any gap that is visibly growing, warrants inspection.
1.5 Distorted Window Frames
What it looks like: Window frames that are visibly out of square, diamond-shaped rather than rectangular. Often the opening is narrower at the top or bottom than at the other end.
Where to look: Looking at window openings from outside with a critical eye.
Urgency: Structural distortion in window frames warrants inspection within 3 months.
Category 2: Interior Signs
Walk through every room of the house looking for:
2.1 Diagonal Cracks at Door and Window Corners
What it looks like: Diagonal cracks emanating from the corners of door openings or window reveals, typically running at 45° toward the nearest building corner.
Where to look: Every doorway and window in the house.
Urgency: Cracks wider than 3 mm, or cracks that have appeared recently, warrant inspection.
Context in Wagga: These are the most common internal crack in brick veneer homes on reactive clay. On Wagga’s H-class clay sites, they are the earliest and most reliable indicator of foundation movement.
2.2 Sticking Doors
What it looks like: Doors that require more force to open or close than they used to, or that no longer latch without force. In extreme cases, doors that cannot be opened at all.
Where to look: Every interior and exterior door in the house.
Important distinction: Doors that stick in summer and ease in winter are likely responding to seasonal moisture changes in the door and frame (wood expands with moisture). Doors that stick year-round or are progressively getting worse indicate structural distortion.
Urgency: Doors that are permanently sticking and are getting progressively worse warrant inspection within 3 months.
2.3 Sticking Windows
What it looks like: Windows (particularly older single-hung or double-hung timber-framed windows) that are difficult to open or no longer close flush.
Urgency: Similar to sticking doors, persistent and progressive sticking warrants inspection.
2.4 Sloping Floors
What it looks like: Floors that are visibly sloping to the eye, or that can be confirmed with a spirit level.
How to check: Place a spirit level on the floor in multiple positions across each room. Measure the slope as millimetres of rise per metre of run.
Urgency scale:
- Less than 4 mm/m: Within typical tolerance, monitor
- 4-8 mm/m: Significant, inspect within 6 months
- 8-12 mm/m: Serious, inspect within 2 months
- Greater than 12 mm/m: Urgent, schedule inspection immediately
Where to look: Particularly near the perimeter of the house (where clay movement is greatest), and in rooms that are closest to large trees.
2.5 Gaps at Skirting Boards
What it looks like: The skirting board (fixed to the wall) has separated from the floor. The floor has dropped away from the skirting, leaving a gap that is either uniform along the wall or tapered (one end has a larger gap than the other).
Urgency: Any visible gap at the skirting board is an indicator of floor movement. A gap greater than 5 mm warrants investigation.
2.6 Bouncy or Spongy Floors
What it looks like: Walking across the floor produces a springy feel underfoot, or the floor deflects noticeably when you jump gently.
Where this occurs: Most common in timber-frame suspended floor homes.
Urgency: A floor that has become progressively more bouncy warrants inspection, it indicates either bearer/joist deterioration or stump failure.
2.7 Squeaking Floors
What it looks like: Floor squeaks and creaks when walked on.
Urgency: Squeaking alone is often just loose fixings and is low urgency. Squeaking combined with other signs (slope, gaps at skirting) is more significant.
2.8 Cracked Floor Tiles
What it looks like: Grout lines cracking, or tiles cracking through the body of the tile.
Urgency: A few isolated grout cracks are often thermal movement, low urgency. Tile cracks in a consistent pattern across an area, or tiles that have popped (hollow sound when tapped) indicate the slab beneath has moved. Inspect within 3 months.
2.9 Walls Out of Plumb
What it looks like: Hold a spirit level vertically against the wall. An out-of-plumb wall indicates the structure has racked or rotated.
Urgency: More than 5 mm out of plumb over 2 metres warrants inspection.
Category 3: Sub-Floor Signs (Older Homes with Accessible Sub-Floor)
Access the sub-floor via the inspection hatch and look for:
3.1 Rotted Stumps
What it looks like: Timber that is soft, discoloured, or crumbling at or below ground level.
Urgency: Any stump showing active rot that is load-bearing should be assessed within 3 months.
3.2 Tilting Stumps
What it looks like: Stumps that lean noticeably from vertical.
Urgency: Tilting stumps that support load are bearing eccentrically and will continue to move. Assess within 3 months.
3.3 Stumps Not Touching Bearers
What it looks like: A visible gap between the top of the stump and the bottom of the bearer it is supposed to support.
Urgency: A stump not touching its bearer provides no support at all. That bearer span is unsupported. Urgent assessment required.
3.4 Mud Tubes
What it looks like: Tan-coloured tunnels of soil and cellulose material on the sides of stumps, on the subfloor walls, or on the soil surface.
Urgency: Active termites require immediate attention, call a licensed pest inspector before anything else.
3.5 Wet or Saturated Soil Under Floor
What it looks like: Clay soil that is visibly wet, or standing water in the subfloor.
Urgency: Persistent moisture in the subfloor has multiple causes (leaking pipe, inadequate drainage, rising damp). All require investigation within 3 months.
Your Urgency Assessment
Score your home:
| Signs Present | Recommended Action |
|---|---|
| None | Routine inspection every 3-5 years |
| 1-2 low-urgency signs | Monitor with photos; inspect in 6-12 months |
| 3+ low-urgency signs | Book inspection within 3 months |
| Any medium-urgency sign | Book inspection within 2 months |
| Any high-urgency sign | Book inspection within weeks |
| Emergency signs (see above) | Call today |
What the Inspection Tells You
A professional foundation inspection gives you:
- Confirmation of which signs are cosmetic and which are structural
- Identification of the likely cause (seasonal movement, tree desiccation, drainage failure, plumbing leak)
- Indication of whether movement is active or historical
- Recommended repair scope and urgency
- Estimated repair cost range
This information is essential before committing to repair costs. The inspection itself is a small fraction of any repair cost and is the only way to make an informed decision.
Frequently Asked Questions
Q: I have 3 or 4 of these signs, does that mean my foundation is failing? A: Multiple concurrent signs are more significant than any single sign, but “foundation failing” is a spectrum. The most common finding after inspection in Wagga is that movement is occurring at a rate that warrants repair within 6-18 months, but is not an emergency. Get an inspection to find where you sit on that spectrum.
Q: My house has sloped floors but has always been this way, should I still worry? A: Long-standing slope is less urgent than newly developing slope. However, if the slope is greater than 8 mm/m, it indicates significant historical movement and the current rate of progression matters. Measure the slope now, then again in 6 months. If it is changing, the movement is still active.
Q: I only have sticking doors, is that enough to get an inspection? A: One sticking door alone, in summer, is probably just seasonal moisture. Multiple sticking doors that are not seasonal, combined with any other sign, warrants an inspection. When in doubt, inspect. The cost of an inspection is trivial compared to the cost of overlooked structural damage.
Q: My home is only 10 years old in Estella, should I expect these signs? A: Yes, some minor signs in the first 10 years are expected in Wagga’s reactive clay. Signs that are progressing rather than stabilising in a 10-year-old home warrant investigation, the initial settlement period should have largely resolved by year 5-7.
Q: How do I know if the movement is getting worse or has stabilised? A: The only way to know is to measure. Take dated photographs of all cracks with a ruler in frame. Check floor slopes with a spirit level and note the reading and date. Re-measure in 6 months. If measurements are unchanged, movement is stable. If they have increased, it is progressive.
Ticking boxes on this checklist? Book a free foundation assessment in Wagga Wagga; if a contractor is confirmed for your area, they’ll carry out an inspection, walk you through what it finds, and tell you honestly what action is needed and when.