The Ticking Clock in Sydney's Strata Buildings
Sydney's strata building stock is ageing. The NSW Government's strata data shows that over 40% of the city's 85,000+ strata schemes were built before 2005 — meaning their waterproofing membranes, concrete protection systems, and structural sealants are now at or beyond their design life.
The problem isn't that buildings fall down. The problem is that remedial defects compound exponentially when left untreated:
- A $2,000 crack repair at Year 15 becomes a $45,000 concrete cancer remediation at Year 25
- A $5,000 waterproofing patch at Year 10 becomes a $120,000 full membrane replacement at Year 20
- A $500 sealant renewal at Year 8 becomes a $30,000 facade water ingress investigation at Year 15
"The single most expensive decision a strata committee makes is the decision to defer remedial maintenance. Every year of deferral typically doubles the eventual cost. We see it constantly — buildings that could have spent $50,000 five years ago now facing $300,000+ remedial programs because water has been penetrating concrete for half a decade." — Ryan Cole, Head of FM & Reactive Services, Cable Co
Types of Remedial Building Works in Strata
1. Concrete Cancer (Spalling and Carbonation)
What it is: Steel reinforcement inside concrete corrodes when carbonation or chloride ingress reaches the rebar. The rust expands (up to 6x the volume of steel), cracking and "spalling" the concrete cover.
Warning signs:
- Rust staining on concrete surfaces
- Cracking parallel to reinforcement lines
- Concrete pieces falling from soffits, balconies, or facades
- Hollow sound when tapped (delamination)
Cost to repair:
| Severity | Description | Cost per m² | Typical Building Cost |
|---|---|---|---|
| Minor | Surface carbonation, no rebar exposure | $150–$300 | $15,000–$40,000 |
| Moderate | Rebar exposed, localised spalling | $300–$500 | $50,000–$150,000 |
| Severe | Structural rebar loss, widespread spalling | $500–$800 | $150,000–$500,000+ |
| Critical | Structural integrity compromised | $800–$1,500+ | $500,000–$2,000,000+ |
Emergency response: When concrete spalling creates a falling hazard (pieces falling from height onto pedestrian areas), this is a P1 emergency requiring immediate make-safe. Cable Co's Command Centre dispatches crews to install exclusion zones, catch nets, or temporary propping within 2 hours.
2. Waterproofing Failures
What it is: Waterproofing membranes on roofs, balconies, planter boxes, and wet areas have a design life of 15–25 years. When they fail, water penetrates the structure — causing damage to units below, promoting concrete cancer, and creating mould hazards.
Warning signs:
- Water stains on ceilings below balconies or roofs
- Efflorescence (white salt deposits) on concrete surfaces
- Mould growth in units below external areas
- Bubbling or lifting of balcony tiles
- Water pooling that doesn't drain
Cost to repair:
| Location | Repair Type | Cost per m² | Typical Area |
|---|---|---|---|
| Roof membrane | Full replacement | $200–$400 | 200–500m² ($40,000–$200,000) |
| Balcony membrane | Strip and re-membrane | $250–$450 | 8–15m² per balcony ($2,000–$6,750 each) |
| Planter boxes | Re-line and waterproof | $300–$500 | 2–10m² ($600–$5,000 each) |
| Wet areas (bathrooms) | Re-waterproof | $150–$300 | 4–8m² ($600–$2,400 each) |
| Podium/car park deck | Membrane replacement | $180–$350 | 500–2,000m² ($90,000–$700,000) |
3. Structural Crack Repair
What it is: Cracks in concrete or masonry that indicate structural movement, settlement, or thermal stress. Not all cracks are structural — but all structural cracks require engineering assessment.
Classification:
| Crack Width | Classification | Action Required |
|---|---|---|
| < 0.1mm | Hairline (cosmetic) | Monitor only |
| 0.1–0.3mm | Fine (may be structural) | Engineering assessment |
| 0.3–1.0mm | Medium (likely structural) | Repair required |
| 1.0–5.0mm | Wide (structural) | Urgent repair + investigation |
| > 5.0mm | Severe (structural failure risk) | Emergency — immediate assessment |
Repair methods:
- Epoxy injection ($200–$400/linear metre) — for structural cracks requiring strength restoration
- Polyurethane injection ($150–$300/linear metre) — for active water leaks through cracks
- Routing and sealing ($100–$200/linear metre) — for non-structural movement cracks
- Carbon fibre strengthening ($500–$1,000/linear metre) — for severely compromised elements
4. Facade Remediation
What it is: External facade defects including render cracking, tile debonding, cladding failure, sealant deterioration, and paint system breakdown.
Why it's urgent in 2026: Following the Opal Tower and Mascot Towers incidents, NSW introduced mandatory facade inspections for buildings over 6 storeys. Non-compliance creates legal liability for owners corporations and their managing agents.
Cost range: $250–$600/m² for full facade remediation depending on access method (scaffolding vs rope access vs EWP).
Emergency Make-Safe: When Remedial Becomes Reactive
Not all remedial work is planned. These scenarios require immediate response:
| Emergency | Risk | Make-Safe Action | Cost |
|---|---|---|---|
| Concrete falling from height | Pedestrian injury | Exclusion zone + catch net | $500–$2,000 |
| Structural crack widening rapidly | Building stability | Engineering assessment + temporary propping | $2,000–$10,000 |
| Waterproofing failure causing flooding | Unit damage, electrical risk | Water extraction + temporary membrane | $1,000–$5,000 |
| Facade tile/render debonding | Falling hazard | Remove loose material + exclusion zone | $800–$3,000 |
| Balustrade failure | Fall risk | Temporary barrier + exclusion | $500–$1,500 |
Cable Co's 24/7 Command Centre handles all remedial emergency make-safe works. When a building manager reports concrete falling from a soffit at 7am, our crew is on site within 2 hours to establish safety measures — before the remedial contractor even answers their phone.
The Remedial Building Assessment: Your Starting Point
Before any remedial program begins, you need a comprehensive building assessment. This is not a visual inspection — it's an engineering investigation using:
- Concrete testing — Carbonation depth, chloride content, compressive strength
- Cover meter survey — Mapping rebar depth and location
- Moisture mapping — Identifying water ingress paths
- Crack monitoring — Gauges installed to measure movement over time
- Core sampling — Physical samples for laboratory analysis
- Thermal imaging — Identifying hidden moisture and delamination
Cost: $5,000–$15,000 depending on building size and complexity
Who does it: Structural engineer (not a builder, not a waterproofer — an engineer)
Output: Remedial scope of works with prioritised staging and budget estimates
Managing Remedial Programs Across a Portfolio
For portfolio managers with multiple ageing buildings, the challenge isn't just fixing one building — it's prioritising across 50, 100, or 200 buildings with competing needs and limited capital.
Cable Co's Portfolio Remedial Approach
- Audit all buildings — Condition assessment and risk ranking (1–5 scale)
- Prioritise by risk — Safety hazards first, then water ingress, then cosmetic
- Stage over 3–5 years — Align with capital works fund capacity
- Bundle similar works — Economies of scale (waterproofing 10 buildings > 1 building)
- Integrate with reactive — Our Command Centre handles emergencies between planned stages
- Report quarterly — Progress, spend, and risk reduction metrics
Get a Remedial Assessment for Your Portfolio
Cable Co's FM Division provides remedial building assessments and staged remedial programs for large portfolios. We coordinate structural engineers, specialist subcontractors, and our own multi-trade crews to deliver remedial works efficiently — with 24/7 emergency make-safe capability between planned stages.
Portfolio enquiries: 1800 117 177 or fm@cable-co.com.au