A structural fault affects how a building stands, carries load, or stays safe over time. Not every crack qualifies. This guide covers when a Perth buyer can legally back out, and gives inspectors a field reference organised by building element.
Can Buyers Back Out Over a Structural Fault?
Buying a home in Perth can move fast, especially when a property is advertised “as is” or the agent wants a clean offer. But one question matters more than any other: if a structural fault is found after your offer is accepted, can you back out?
Only if your contract allows it. WA has no automatic cooling-off period for real estate contracts. Once the seller accepts your offer and that acceptance is communicated, the contract is usually binding. Your ability to withdraw depends on the conditions written into the Offer & Acceptance, not on the defect itself.
What Does “As Is” Actually Mean?
“As is” means the seller is selling the property in its current condition and isn’t promising to fix anything before settlement. It does not mean the house is safe, and it does not automatically mean you can cancel later if a defect is found. The listing doesn’t protect you — the contract wording protects you.
When Can You Actually Back Out?
- No inspection clause: you’re usually committed, even if a serious defect turns up later.
- Standard building inspection clause: some protection, but often limited to major structural defects only, under AS 4349.1-2007.
- Strong satisfactory inspection / due diligence clause: the strongest protection — you can exit if the report simply isn’t satisfactory to you, at your discretion.
Structural Defect vs Major Structural Defect
A structural defect is a fault or deviation affecting the intended structural performance of a building element — it may affect load-carrying ability, stability, or serviceability, and can involve walls, roof frames, slabs, footings, beams, columns, or timber members.
A major structural defect is serious enough that rectification is required to avoid unsafe conditions, loss of utility, or further deterioration — think significant movement or instability, unsafe or collapse risk, serious deterioration of structural members, or a need for urgent repair.
Buyer back-out indicator: possible if the contract allows it. If the report identifies a major structural defect and your WA contract includes the right building inspection clause, you may be able to back out — but contract wording is what decides it.
Key takeaways:
- Not every crack is structural.
- Not every structural defect is major.
- Contract wording affects buyer rights.
- Inspection findings must be assessed in context.
Wall Crack Width Guide
| Crack Width | Meaning |
|---|---|
| Under 1 mm | Usually hairline or minor |
| 1–5 mm | Slight cracking, assess context |
| Over 5 mm | Red flag, assess cause |
| 5–15 mm | Moderate concern, possible movement |
| 15–25 mm | Serious concern |
| Over 25 mm | Very serious, engineering assessment recommended |
Not automatic: a crack over 5 mm is a red flag, not an automatic back-out right. The buyer may only back out if the report shows a qualifying major structural defect and the contract allows it. Pattern, location, movement, distortion and associated symptoms all matter.
Watch for: diagonal cracks, stair-step cracking, widening at one end, repeated repaired cracks, sticking doors or windows, sloping floors, and wall bulging or leaning.
External Load-Bearing Wall Faults
External wall cracking is one of the clearest structural indicators in a Perth home. Key patterns include:
- Stair-step cracking — a common sign of differential footing movement.
- Diagonal cracks from window/door corners — often indicates stress from opening corners.
- Horizontal cracking — may indicate loss of wall restraint or out-of-plane pressure.
- Vertical cracks through bricks and mortar — may indicate settlement, shrinkage, or thermal movement.
- Bulging or leaning walls — out-of-plane movement, lateral pressure, or possible foundation failure.
- Cracks over 5 mm, with sticking doors, or with sloping floors — all raise the level of concern.
A single crack is not enough — crack pattern plus movement signs matter most. Escalate concern when cracks are active, widening, repeated, diagonal, stepped, or linked with distortion elsewhere in the home.
Internal Wall & Ceiling Movement Signs
Internal partition walls are often non-load-bearing, so fine hairline cracks under 1 mm, cracks confined to paint or plaster, and minor shrinkage cracks near picture hooks are usually cosmetic.
Possible structural warning signs include diagonal cracks above doors, cracks wider than 5 mm, cracks running floor to ceiling, cracks matching an external wall crack, cornice or ceiling-to-wall separation, sticking doors, uneven floors, and reopened patched cracks.
Symptom only: internal cracks do not automatically let a buyer back out. The underlying cause must be structural, clearly reported, and covered by the contract.
Roof Structure Red Flags
Roof framing is one of the main areas structural faults are identified in Perth homes. Red flags include a sagging roofline, bowed ridge line, sagging roof plane, cracked or split rafters, broken struts, damaged underpurlins, failed collar ties, sagging ceiling joists, cracked beams, missing supports, cut or notched roof members, a removed support wall below, heavy roof loads on inadequate framing, and failed tie-downs or connections.
Inspect next: check the roof void where safely accessible — many roof structure problems are only visible from inside the roof space.
Roof Void Timber & Chemical Delignification
General timber deterioration in the roof void includes cracked timber, split members, timber rot, water damage, loss of section, failed bearing or fixings, termite damage, and soft or crumbly timber.
Chemical delignification is a separate process: lignin is the natural binder holding timber fibres together, and delignification breaks that binder down, leaving timber hairy, fibrous, soft, crumbly and weaker. Warning signs include a furry or hairy surface, fibres separating easily, soft or powdery texture, a surface that scrapes away, and multiple roof members affected.
Key point: it becomes structural when it affects rafters, underpurlins, struts, beams, joists, or other load-bearing roof members.
Termite Damage to Structural Timber
Termite damage becomes a structural concern when it affects rafters, ceiling joists, floor joists, bearers, beams, posts, wall framing, timber lintels, subfloor timbers, or roof supports.
Key warning signs: hollow-sounding timber, frass (termite droppings) or mud leads, damaged or crumbling bearing ends, sagging floors or roofs, visible cavities or galleries in timber, previous damage with no repair evidence, and active termite attack.
Termite activity is a pest issue. Termite damage to load-bearing timber is a structural issue.
Floor, Subfloor & Footing Movement
Floor symptoms: sagging floors, bouncy or springy floors, uneven floor levels, sloping floors, and gaps at skirtings.
Subfloor faults: damaged joists or bearers, rotten stumps or posts, corroded steel supports, termite-damaged subfloor timbers, loss of bearing, failed connections, and poorly supported additions.
Footing movement signs: large recurring wall cracks, gaps around doors and windows, doors not closing properly, separation between additions and the original house, and reopened repaired cracks.
The whole building sits on the footing system — movement here often shows up elsewhere first, which is why floor, wall and roof symptoms need to be read together, not in isolation.
Concrete Slab, Beams & Columns
Concrete defects to watch for include major slab cracking, slab heave (upward movement from reactive soil or moisture), slab settlement, cracks with vertical displacement, concrete spalling, exposed or corroded reinforcement, concrete cancer, cracked beams or columns, deflected slabs, and honeycombing.
Concrete cracks are more serious when they are wide, displaced, active, rust-stained, leaking, or linked with movement. Escalate concern when there’s displacement, active corrosion, deflection, or evidence of loss of strength.
Lintels, Renovations & External Structures
Lintels & openings: rusted steel lintels, sagging brickwork above windows or doors, cracks above openings, insufficient bearing, and unsupported openings.
Renovations & wall removal: removed load-bearing walls, poor open-plan renovations, incorrect beams, roof members cut for services, and extensions not properly tied into the original building — particularly relevant given how common DIY renovations are in older Perth homes.
Retaining walls: leaning or bulging walls, cracking, drainage failure, and movement affecting the dwelling.
Balconies, decks & verandahs: rotten joists, termite-damaged members, corroded steel posts, cracked balcony slabs, loose balustrade connections, and verandahs pulling away from the building.
Poor alterations and failed external structures can create serious safety and structural risks — and are frequently missed if not specifically checked.
Frequently Asked Questions
Does WA have a cooling-off period for property purchases?
No. Once an offer is accepted, there is no automatic cooling-off period in Western Australia.
Is a crack over 5mm always a structural defect?
No. It’s a red flag requiring assessment, not an automatic classification. Cause, pattern, movement and location all matter.
What’s the difference between a structural defect and a major structural defect?
A structural defect affects a building element’s intended performance. A major structural defect is serious enough that rectification is needed to avoid unsafe conditions, loss of utility, or further deterioration.
Does a standard building inspection clause cover all defects?
No. Standard clauses under AS 4349.1 usually focus on major structural defects only, excluding items like wiring, windows, doors, ceiling linings, tiling and plastering.
Is termite damage automatically a structural issue?
Only if it affects load-bearing timber such as rafters, joists, bearers, beams, or wall framing. Termite activity itself is classed as a pest issue.
What’s the strongest inspection clause a buyer can use?
One that lets the buyer exit if the report is not satisfactory to them, at their absolute discretion, rather than one limited to major structural defects only.
Know What You’re Buying Before You Sign
StructSure Building Inspections helps Perth buyers understand the true condition of a property, and gives inspectors a consistent structural reference to work from.
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