Three quotes come in to fix concrete cancer on a Sydney apartment block. One is $180,000. One is $240,000. One is $310,000.
The strata committee wants to go with the cheapest. The engineer who wrote the scope says that’s a mistake. And nobody can agree on why the prices are so far apart.
This happens in strata buildings across Sydney all the time. Most of the time, the gap has nothing to do with one builder being leaner or smarter. It’s there because the three quotes aren’t for the same job.
The cheap quote has assumptions baked into it. It assumes the concrete damage stops at what you can see. It assumes the work can be done from a scissor lift, not scaffold. It assumes the waterproofing can be patched, not replaced. Any of those might turn out to be true. Or they might not. If they’re wrong, the difference comes back as variations once work has started, when the committee has few options left and the builder knows it.
If you know how remedial building gets bought in Sydney and where the risks sit, you can make a proper decision instead of just picking the lowest number on the page. If you need a remedial builder who’ll give you the full scope up front, not a low entry price with variations to follow, start with the assessment. Not the quote.
Start With the Scope, Not the Quote
On a well-run remedial job, the quote isn’t where things start. The scope is.
The scope should come from an independent look at the building’s condition. Ideally that’s done by a building consultant or structural engineer who isn’t also quoting for the work. It should say what’s wrong, where it is, how far it goes and how it needs to be fixed so it stays fixed. Then it goes out to builders to price.
When every builder prices the same scope, you can compare the quotes. If one is higher, you can see why. Maybe they’re using a better waterproofing system. Maybe they’ve allowed for more detailed quality checks. You can decide whether that’s worth paying for. At least you’re comparing like with like.
When each builder writes their own scope, you can’t. One quote might include a whole new waterproofing membrane. Another might just patch it. One allows for scaffold, another assumes rope access. Those are different jobs, and comparing the prices tells you nothing.
A good scope for concrete spalling repairs goes location by location. It names the repair system, down to the products and how thick they go on. It sets out how the builder will get access, what waterproofing each area needs, when the engineer will stop and inspect the work, and what the defects liability terms are. A quote that answers that scope should go through it line by line.
If a quote turns up as one lump sum with a couple of lines of description, the builder has made their own calls about what the job is. Some of those calls might be fine. Others might be the reason the price looks so good.
The Trouble With Variations
A variation is a change to the agreed work after the contract is signed. On remedial jobs, some variations can’t be avoided. You open up a section of facade and the damage behind it is worse than it looked from outside. That’s nobody’s fault. It needs to be priced and approved, and that’s that.
The problem is when variations are used to claw back margin that was never in the quote. A builder wins the job cheap, then drip-feeds variations until the final bill matches what the job really cost. That’s not honest. It still happens, and it happens more in remedial work than in new builds, because nobody really knows how bad the damage is until the work starts.
Your protection against this sits in how you buy the work, not in the contract.
Getting the scope right before anyone prices it cuts the risk. If an independent engineer has done a proper condition assessment, including opening things up and testing where needed, there’s less left to find. There will still be some surprises. But the builder is pricing what’s actually there, not a best-case guess.
Asking for itemised quotes helps too. If the quote breaks out scaffold, concrete repair, waterproofing, protective coating and make-good on their own lines, you can check a variation against them. A claim for “extra concrete repair at location 12A” can be measured against the rates in the original quote. With a lump sum and a vague scope, there’s nothing to measure it against.
Then there’s oversight during the build. An independent superintendent or consultant can run the contract in a way a strata manager without building training can’t. They review variation claims, approve or push back on them based on the contract, and only sign off progress payments for work that’s actually done. That’s normal on commercial jobs. It’s used far too little on strata remedial work.
How the DBP Act Changes Things
Since July 2021, remedial work on Class 2 buildings in NSW has come under the Design and Building Practitioners Act 2020. Class 2 covers residential apartment buildings. This isn’t a small box to tick. It changes how some remedial work has to be bought and built.
If the job includes waterproofing that’s part of the building’s outer skin, a registered design practitioner has to prepare a regulated design before work starts. That design has to be lodged on the NSW Planning Portal. Without it, construction can’t legally begin.
So for any job that involves waterproofing balconies, roofs, podium decks or facades, the order goes like this. First the assessment and diagnosis. Then the regulated design by a registered practitioner. Then quotes and construction. You don’t go straight from the assessment to builder quotes.
If a builder quotes straight from a site visit and doesn’t mention the DBP Act design requirements, one of two things is going on. Either they don’t know about them, or they’re not being upfront about what the job legally needs. Either way, it’ll come back to bite you. Usually it’s when the certifier or council asks for the regulated design and nobody has one.
The builders doing the work also have to be registered under the Act. You can check any builder’s registration before you sign. For apartment buildings in Sydney, DBP registration is the bare minimum. It doesn’t set anyone apart.
Access Is Where the Budget Goes
On a multi-storey building, you have to get people and gear to parts of the building you can’t reach from the ground. How you do that makes a big difference to the cost and how long the job takes. It might be tube and fitting scaffold, system scaffold, rope access or elevated work platforms.
Scaffold on a Sydney apartment building isn’t cheap. Depending on the height and footprint of the building, it can be 30 to 50 percent of the whole project cost. That’s not unusual, and it’s not a rip-off for what’s involved. But it means the access assumption in a quote has a huge effect on the final price.
If a builder assumes rope access for work that really needs scaffold, that quote is headed for a big variation once access is sorted out properly. If a builder assumes scaffold where rope access would do the job safely, they’ve quoted more than you need to spend.
The right choice depends on the building’s height and shape, what the work involves, the site conditions for putting up scaffold and the work health and safety rules for that scope. It’s a technical question. It should be answered in the scope before quotes go out, not left for each builder to work out on their own.
When access is a big part of the cost, think about fixing several problems in one go. Scaffold that goes up for concrete spalling on the north side can also be used for waterproofing and coating work on that side, for not much more. Putting scaffold up twice for two separate jobs costs a lot more than doing it once and planning it well.
What QA Paperwork Is Really For
Every remedial contract should ask for quality assurance records. What builders actually hand over varies a lot, and the gap between good and poor records matters more than most committees realise.
On a concrete cancer job, the minimum should cover the whole life of each repair. That means photos of every spot before breakout, and again after breakout showing how far the rusted steel goes. It means a record of how the surface was prepared and what state it was in before the repair went on. It means batch certificates for the repair mortars and other products. Then photos of each finished repair before it’s coated, and a completion certificate from the superintendent or engineer saying the work meets the spec.
This isn’t paperwork for the sake of it. It’s your proof the work was done right, and it matters in a few real situations.
If a repair fails within the defects liability period, the records are how you work out why and who’s responsible. Without them, there’s no record of what went on, where, or to what standard.
If a unit or the building sells, buyers and their inspectors will look for a maintenance history. The QA records are part of it.
If the owners corporation is chasing the original developer under the statutory warranties, the records show the defect was found, an engineer scoped it independently and the repair met a set standard. That can affect how much the claim is worth.
And if NSW Fair Trading uses its enforcement powers under the 2025 strata changes, a scheme that can show a regular inspection program and a well-run repair record is in a much stronger spot than one that can’t.
What Strata Managers Can and Can’t Do
Strata managers do important work. They handle the admin, the money and the governance of a scheme, and most do it well. But most aren’t trained to judge a remedial scope, weigh up a builder’s method, read a concrete repair spec or decide whether a variation claim is fair.
That’s not a dig at them. Remedial work is complex. It takes knowledge of how buildings fail, how materials behave, structural engineering and the NSW rules around strata defects. Nobody expects a strata manager to have all of that.
The trouble starts when the strata manager is the main technical link between the owners and the builder, with no independent eyes on the scope, the method or the work. At that point, the owners are relying on the builder to check their own work. That’s not quality control.
Bringing in an independent consultant or engineer to scope the defects, review quotes, run the contract and sign off the finished work does cost money. On a big job it’s usually around three to eight percent of the construction value. Compare that to paying for repairs that fail in a few years, or approving variations the scope never justified. The oversight pays for itself.
Choosing a Remedial Builder in Sydney
The credentials that matter here are specific, and you can check every one of them.
Start with a current NSW builder’s licence, which you can check through Service NSW before anything is signed. DBP Act registration for work on Class 2 buildings is required, not optional. Home Building Compensation Fund cover protects residential work if the builder goes broke, dies or disappears mid-job, and if it applies to your project, get the certificate before you pay a deposit. Then ask for certificates of currency, not verbal assurances, for public liability insurance that matches the contract value, workers compensation covering everyone on site including subbies, and professional indemnity for any design work the builder is doing.
Past the paperwork, two questions tell you a lot. How do you handle parts of the job where nobody knows how bad the damage is until it’s opened up? And how do you manage and approve variations?
A good answer to the first is a clear method: agreed unit rates and set triggers for when they apply. A good answer to the second is a written variation process, with the superintendent approving each one before the work goes ahead. A builder who answers like that is being honest about how remedial jobs really work.
A builder who tells you variations hardly ever come up on their jobs is either working on very well-scoped projects or not being straight about how their contracts tend to end.
Remedial building isn’t complicated in theory. The building has worn out in places. Someone needs to work out exactly what’s wrong, spell out how to fix it, do the work to that spec and keep records. What makes it hard in practice is the buying. Get that right, and the job has a far better chance of delivering what it promised.
