Coogee and Randwick sit next to each other but weather quite differently. Coogee is a beachfront suburb of interwar flats on a steep bowl above the sand. Randwick, roughly a kilometre inland and up the hill, is freestanding Victorian and Federation housing under a heavy tree canopy.
That short distance changes the dominant problem entirely, and it is worth knowing which side of it your property sits on.
Coogee: salt, density and interwar flats
Coogee is dominated by 1920s to 1950s apartment blocks, packed onto a steep amphitheatre facing the beach. Almost everything has some ocean exposure and the front rows have a lot.
The usual coastal list applies — hazing glass, tea-staining stainless, chalking paint, corroding fixings, sand in the gutters. What is specific to Coogee is the age and construction of the flats.
Interwar render that has been repainted five or six times delaminates readily. Concrete balcony edges spall as reinforcement corrodes. Original steel window frames rust and stain the render below them. Pressure on any of these accelerates the failure rather than cleaning it.
The steepness matters too. Many blocks are built into the slope with the rear elevation below ground level or up against a rock cut, which creates a permanently damp face that will grow mould regardless of how well the front is maintained.
Randwick: canopy, shade and sandstone
Randwick is a different environment. Salt reaches it but at a fraction of the beachfront load, and the dominant factors become tree litter and shade.
Large figs, brush box and plane trees produce constant litter that fills gutters faster than the standard annual advice accounts for. Fig fruit and leaf tannin stain sandstone paths, light-coloured driveways and paving — and that staining is chemical, not surface dirt, so pressure removes stone rather than stain.
Shaded southern elevations and southern roof pitches stay damp and grow mould and lichen continuously. Washing takes off the visible layer and leaves the organism; in permanent shade it re-establishes within a season, so it needs treating at the root.
Sandstone is everywhere in Randwick
Randwick has an unusual amount of exposed sandstone — cuttings along the streets, retaining walls, kerbing, gate piers, front fences and house plinths. Much of it is original and much of it is a century old or more.
Old sandstone that has already begun to hollow or flake is fragile. High pressure takes the weathered face off in sheets and it does not come back. Low pressure, clean water and time is the only responsible approach.
Sealing is a case-by-case decision rather than a default. Sealing stone that is holding moisture from behind — a retaining wall with wet ground on the other side, for instance — traps that moisture and makes the deterioration worse.
Roofs across both suburbs
Terracotta Marseille tiles and slate dominate the older housing. Both become brittle with age and neither should be walked casually.
Old terracotta is porous and holds lichen tenaciously, particularly on shaded pitches. It responds to treatment and dwell time, not to force — pressure washing terracotta strips the glaze, opens the surface, and guarantees the lichen comes back faster.
Valley gutters on complex Federation rooflines in Randwick are usually worse than the eaves and are frequently skipped.
Heritage and precinct traffic
Randwick has several heritage conservation areas along with individually listed properties, so original fabric, repointing and paint removal are worth checking with Randwick City Council before proceeding.
The hospital and racecourse precincts add practical constraints — heavy traffic, restricted parking and limited standing room for a work vehicle on the surrounding streets. It is a scheduling issue rather than a technical one, but it affects when work can realistically happen.
What we’d prioritise
- In Coogee: low pressure on interwar render, spalling concrete and steel window frames
- In Coogee: rinse sand off before brushing, and clear it from gutters
- In Randwick: increase gutter frequency under heavy canopy and clear valley gutters
- Treat tannin staining chemically; pressure removes stone, not stain
- Low pressure only on old sandstone that is already hollowing or flaking
- Treat shaded elevations and southern roof pitches at the root, on a cycle
- Confirm heritage status with Randwick City Council before touching original fabric
Related: the Eastern Suburbs exterior cleaning guide, sandstone cleaning and sealing, cleaning roof tiles without damage, exterior cleaning in Coogee and Randwick.
