Project
Opened in 1935, the iconic Merewether Ocean Baths, New South Wales, are the largest of their kind in the southern hemisphere. The facility is owned and managed by the City of Newcastle, with significant upgrades in 2014 involving the addition of two large ocean baths, one deep pool with diving blocks and a shallow pool with a sandy beach. Achieving a durable and attractive interior finish on these pools required a tailored coating system that can withstand multiple challenges.
Project partners
• Asset owner: City of Newcastle
• Applicator: City of Newcastle
Coatings
• 1st coat: Dulux® Durebild® STE @ 125-microns (μm) white
• 2nd coat: Dulux® Durebild® STE @ 125-microns (μm) white
What was the challenge?
Merewether Oceans Baths incurred high maintenance costs due to algae growth on the porous concrete interior surfaces, which required the pools to be emptied fortnightly. The concrete is water-blasted to remove the algae then a biocide is sprayed on to inhibit repeat growth. The pools would then be re-filled before the costly exercise was repeated a fortnight later.
A solution was proposed in 2020, in the form of two coats of Durebild STE in White. This system can be applied direct to concrete to create a durable surface and this system is compliant for use in potable water as per AS/NZS 4020.2018.
When uncoated, algae growth strands on the concrete surfaces would reach 30 to 45cm long before blasting was conducted. Six months after the first application of Durebild STE, there was no algae growth of any significance. Additionally, as the white finish reflects sunlight, the water had an attractive, mediterranean blue appearance.
Regular maintenance coating is carried out every six to twelve months to refresh the finish. This has represented a significant cost saving for the City of Newcastle.
What were the inspection findings?
After four years of a regular 6-monthly maintenance cycle, a visual inspection of the Merewether Ocean Baths concrete surfaces showed the coatings system to be performing as expected, with the finish in excellent condition.
Coating rating after 4 years
Rating 1*
Up close
Dulux® Protective Coatings Trade Specialist, Greg Scott inspected the sections of the pool surfaces that were not underwater. He saw no evidence of deterioration, aside from some minor delamination of the line marking on the disabled access ramp.
“The coating system has successfully inhibited algae growth, while the bright white finish reflects sunlight and gives the water an attractive, vibrant blue appearance. Locals and visitors regularly comment on the outstanding appearance of the pools and have complimented the council on their decision to paint their interiors," Greg reports.
System benefits
• Durebild STE is a high-performance surface tolerant epoxy that is an ideal maintenance coating. It has been developed especially for Australian conditions, is suitable for immersion in fresh or salt water, resists chemicals and offers excellent asset protection.
* Coating Inspection 5-Level Rating System
Coatings are inspected to determine the degree of deterioration. Ratings indicate the following condition status:
1. No film damage other than dirt and minor staining
2. Soiled, stained, ingrained dirt, chalking or loss of gloss
3. Minor film damage (cracking, flaking or erosion of topcoats) in small areas
4. Minor corrosion where up to 0.5% of the base metal is showing signs of rusting.
5. Widespread and excessive corrosion and damage
