Perfect Remediation was engaged to refurbish and recoat the steel sheet pile retaining walls across two basement levels of a mixed use building at Collaroy Beach, on Sydney's Northern Beaches.
The works ran through July and August 2026, alongside a live strip out and demolition programme in the building above.
The sheet piles had been in the ground since the basement was formed. Years of moisture behind and around the piles had left heavy surface corrosion, flaking scale and an old coating that had lost its grip in large sections. Before any new protective coating could be applied, every square metre of exposed steel had to be brought back to a sound, dry and consistent surface.
This was also the first full site deployment of our own laser rust, paint and coating removal plant, so the job doubled as a working trial of where laser cleaning earns its place on structural steel and where it does not.
Scope of works
Perfect Remediation delivered the full preparation and protective coating package to the sheet piling across basement levels one and two.
- Scraping and removal of loose rust, scale and debris from the full face of the piles on both levels
- Pulling gravel and fill back from the base of the piles so the whole face could be reached
- Laser cleaning of rust and failed coating from the sheet pile faces
- Mechanical surface preparation using variable speed grinders with flat pads, flap discs and wire cup brushes
- Removal of heavy rust nodules and edge build up using a percussion tool fitted with a vinyl blade
- Hand wire brushing behind pipework and services where no powered tool could reach
- Sweeping and industrial vacuuming of both basement levels to clear rust dust before coating
- Solvent wipe down and application of a two coat epoxy protective coating system
- Fume, dust and ventilation control for the duration of the works
- Site specific SWMS, daily diaries and site inductions through the head contractor's system
Challenges
A basement is close to the worst environment you can pick for this kind of work, and the programme did not allow the building above to stop.
- No natural ventilation. Laser cleaning burns coating off the steel and the fume travels straight up the wall face. Hand held extraction hoses were not capturing it, so the set up moved to multiple extraction fans plus a mobile smoke purifier, with a capture hood held flat to the wall.
- Lead in the existing coating. The works were run on the basis that lead was present, which sets the extraction class and the respiratory protection rather than leaving it to preference. Crews worked in P3 rated respirators with face shields and full PPE.
- Reach and access. The laser umbilical runs about ten metres, one section of wall stood roughly three metres high, and services and pipework stood off the wall in places with no gap for a powered tool.
- Wet substrate. Several areas, including sections of basement one, were too damp to coat and had to be dried and reprogrammed rather than painted over.
- Rust dust everywhere. Preparation on this scale coats two full basement levels in fine rust dust. Sweeping and vacuuming before coating was a job in its own right, not a clean up afterthought.
What the laser did, and what it did not do
This part is worth recording plainly, because it changed the method on site and it is the question every client asks.
Laser cleaning removes coating and light to moderate rust well. It does it with no abrasive, no water, no blast containment and very little waste, which is why it suits detail, edges, confined pockets and anywhere a blast pot would be impractical.
On this substrate it left a grey oxide film rather than bare steel. We tested that by grinding the grey areas back, and the film came away, which told us the laser had burned the corrosion rather than removed the full corrosion layer. For a coating system that relies on a defined, sound surface, that finish is not enough on its own.
So the method changed. The laser carried the coating removal and the detail work. The final substrate was achieved mechanically, with flat pads, flap discs and wire wheels on variable speed grinders, run with a small amount of water to hold the dust down, then wiped back with thinners before the first coat. The epoxy held well on that finish.
On a structure of this size and condition, abrasive blasting would have reached the specified finish faster. We would say the same to any client asking whether laser is the right tool for a job like this one. Laser is a precision instrument, not a bulk removal method.
Our approach
Stage 1 - Set up and access
- Site induction, exclusion zones and temporary lighting through both basement levels
- Three phase supply confirmed and the laser and purifier tagged and plugged
- Gravel and fill pulled back from the base of the piles to expose the full face
- Sheet pile refurbishment SWMS issued and loaded into the head contractor's system before any work started
Stage 2 - Bulk preparation
- Loose rust, scale and debris scraped off across both levels
- Heavy rust nodules and edge build up knocked back with a percussion tool and vinyl blade
- Flat faces prepared with variable speed grinders, flat pads and flap discs, with water used to control dust
Stage 3 - Laser cleaning and detailing
- Laser cleaning to coated faces, welds, edges and pockets, with extraction and fume capture at the work face
- Wire cup brushing to welds and rough areas the laser could not level
- Hand wire brushing behind pipework and services
Stage 4 - Clean down and coating
- Full sweep and industrial vacuum of both basement levels, including the spoon drains
- Steel dusted off and wiped down, then solvent wiped by the applicators
- Two coat epoxy protective coating system applied, with damp areas held back until dry
- Final inspection with the client, and remaining rough rust areas ground back before sign off
Project outcome
Both basement levels of sheet piling were prepared and coated, and the steel was handed over protected and inspected.
- Full face preparation and a two coat epoxy system to the sheet piles across basement one and basement two
- Fume, lead dust and rust dust controlled inside an enclosed basement while the building above stayed in work
- Damp sections identified and held back rather than coated over, so the system was applied to a sound surface
- Client inspection items closed out on site before demobilisation
- A tested, documented position on where laser cleaning belongs in a coating specification, which we now use when pricing this work
Where laser cleaning does earn its place
The trial was worth running. Based on this project, laser cleaning is the right call when:
- the area is detailed, confined or full of services, and setting up a blast is not practical
- abrasive, grit recovery or water cannot be introduced to the space
- the substrate underneath must not be damaged, for example heritage steel or timber
- coating removal is the goal rather than achieving a heavy blast profile
- the work is close to occupied or operating areas where containment is the main cost driver
For open, heavily corroded structural steel over large areas, blasting still wins on rate.
Talk to us about steel refurbishment and coating
Perfect Remediation delivers structural steel repairs and remediation, surface preparation and protective coating works across NSW and Queensland, in basements, plant rooms, live buildings and infrastructure. Call 02 7912 3054 or send us the drawings and photos and we will tell you honestly which preparation method suits the asset.
Perfect Remediation and Refurbishment acknowledges the Aboriginal and Torres Strait Islander people as Traditional Custodians of the country on which we live and work. We pay our respects to the Traditional Custodians and Elders past, present and future, and honour their connection to the land and ongoing contribution to society.