Concrete Cancer Repairs and DBPA: Do You Need a Regulated Design?

Concrete cancer is the single most common structural defect in ageing Class 2 buildings across NSW. Carbonation creeping through cover concrete, chloride attack in coastal buildings, water ingress through cracked soffits — if you work on strata buildings built before the 2000s, you've seen it hundreds of times. The repair work feels routine. Break out, treat the steel, patch, coat, move on.

But under the Design and Building Practitioners Act 2020, "routine" is not a regulatory category. The question the DBPA asks is simple: are you designing how a structural building element will be repaired? If you are, that repair specification is a regulated design — and you need to be registered, declare it, and lodge it on the NSW Planning Portal.

A lot of concrete repair work that engineers have treated as standard remedial practice for decades now falls squarely within the DBPA's scope. Here's how to tell where the line sits.

When Concrete Repairs ARE a Regulated Design

The trigger is design intent. If you are making decisions about how a structural element will be reinstated, strengthened, or protected — you're designing. These are the concrete repair scenarios that cross the line:

Specifying the Repair Methodology

When your report or specification prescribes the repair process — breakout extents, reinforcement treatment, primer application, repair mortar type, curing requirements — you are designing a structural repair. A specification that says "break out carbonated concrete to 25mm past the rear face of reinforcement, treat bars with zinc-rich primer, and reinstate with polymer-modified repair mortar to the original profile" is a set of design instructions. A contractor can procure and build from those words. That is a regulated design.

Designing Structural Strengthening

Where section loss is significant — heavily corroded reinforcement, spalled soffits with exposed tendons, reduced load-bearing capacity — the repair often goes beyond patching. If you're designing carbon fibre wrapping, externally bonded steel plates, supplementary reinforcement, or load redistribution measures, that is structural design by any definition. The DBPA treats it accordingly.

Specifying Protective Coating Systems

Protective coatings applied as part of a remediation strategy — anti-carbonation coatings, chloride-inhibiting surface treatments, elastomeric crack-bridging systems — are part of the design when they serve a structural protection function. If the coating is integral to the long-term durability of the repair (and it almost always is), it forms part of the regulated design.

Electrochemical Treatments

Cathodic protection systems, electrochemical chloride extraction, or re-alkalisation treatments are specialised engineering solutions. Specifying these systems — including anode layout, current density, monitoring provisions, and design life — is unambiguously a regulated design for a structural building element.

Any Repair Affecting Structural Adequacy

The broadest test: if the repair relates to an element that carries load, and the repair methodology affects whether that element can continue to carry load safely, it is a structural regulated design. Balcony soffits, transfer beams, column bases, suspended slabs, retaining walls — these are all structural elements, and designing their repair is designing a building element.

When Concrete Repairs Are Probably NOT a Regulated Design

Not every patch of render constitutes a regulated design. There are genuine boundaries:

• Minor cosmetic patching — filling a surface blemish with render or repainting a non-structural element. If there's no reinforcement involvement and no structural function, there's no regulated design.
• Inspection-only scope — conducting a condition assessment, documenting defects with photos and locations, and recommending that a remediation design be prepared. If you stop at "what's wrong" and don't prescribe "how to fix it," you haven't designed anything.
• Maintenance schedules — recommending inspection intervals, cleaning regimes, or recoating cycles without specifying products or methods. These are maintenance recommendations, not design decisions.

The Grey Area: "Repair to Engineer's Specification"

This is the trap that catches the most practitioners. You write a condition report. In the recommendations section, you describe the repair methodology in enough detail that a contractor can carry out the work. You might even call it "indicative" or "subject to confirmation on site." But the reality is: if the contractor builds from your words, you specified the design.

The test is practical, not semantic. If your document is the thing the builder follows to execute the repair, it is the design — regardless of what you titled it. A "Condition Assessment Report" that contains breakout extents, reinforcement treatment methods, repair mortar product names, and coating specifications is a design specification wearing a different hat.

Many engineers have been issuing these hybrid documents for years without realising they've become the design practitioner on the project. The Building Commission doesn't care what you called the document. They care what it contains and whether it was declared and lodged.

Common CIRD Deficiencies in Concrete Repair Designs

Even when engineers correctly identify their concrete repair work as a regulated design, the Comprehensive Inspection and Record Documents (CIRDs) often fall short. These are the deficiencies the Building Commission flags most frequently in concrete remediation CIRDs:

• No breakout extents specified — the CIRD says "break out defective concrete" without defining the depth or extent beyond reinforcement. The builder is left to guess, and the inspector has nothing measurable to check against.
• No reinforcement treatment method — corroded steel is exposed but the specification doesn't state whether to use rust converter, zinc-rich primer, cementitious passivation coating, or another treatment. Product selection is a design decision.
• No repair mortar product specified — "repair with suitable mortar" is not a specification. The CIRD should name the product or performance class (e.g., Class R4 structural repair mortar to AS 1012/EN 1504) and application method.
• No protective coating system specified — the repair is patched but no anti-carbonation or protective coating is included, leaving the repaired element exposed to the same deterioration mechanism that caused the original failure.
• No structural adequacy assessment — where reinforcement has significant section loss, there's no engineering assessment of whether the element can still carry its design loads after repair, or whether strengthening is required.

Each of these gaps is a potential audit finding. The Building Commission expects concrete repair CIRDs to be specific enough that an inspector can verify every step of the repair against the documented design intent.

The Condition Report That Became a Specification

This scenario plays out regularly. An engineer is engaged to inspect a building and report on its condition. The fee proposal says "condition assessment." The report is titled "Condition Assessment Report." But somewhere around page 15, the recommendations section starts specifying repair products, breakout depths, coating systems, and construction sequences.

At that point, the engineer has produced a regulated design — possibly without realising it. There's no DBPA registration check, no design compliance declaration, no lodgement on the Planning Portal. The report goes to the strata manager, a builder is engaged, and the work proceeds based on the engineer's specifications.

If the Building Commission audits that project, the engineer is the design practitioner — and an unregistered, non-compliant one at that. The fix is straightforward: either keep your condition reports as pure observations and direct the client to engage a registered design practitioner for the repair design, or accept that your report is a design document and comply with the DBPA accordingly.

There's no wrong answer, as long as you're honest about which document you're actually producing.