Defect type
Critical · 2–5/5
Reactive Clay Soil Movement Affecting Foundation
Seasonal expansion and contraction of reactive clay soils causing cyclical foundation movement, wall cracking, and floor level changes. Prevalent in Sydney Western Suburbs and some Perth clay zones. Severity depends on soil class (H, H1, H2, E) and footing design adequacy.
Causes
- Reactive clay soil (Class H to E) with seasonal moisture variation
- Tree root desiccation drawing moisture from foundation zone
- Inadequate footing design for actual soil reactivity
Symptoms to look for
- Recurring cracks that open in summer and close in winter
- Doors and windows binding seasonally
- Uneven floor levels varying with season
Remedies
- Soil moisture management via consistent garden watering regime
- Tree root barriers for trees within influence zone of footings
- Underpinning to stable founding depth if movement exceeds serviceability limits
Critical
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Findings in this category skew high severity. If you are under contract, we can usually book inside the cooling-off window. Every inspection includes 12 months of free advice.
Same category