Sandstone care in Killarney Heights

Killarney Heights sits on a peninsula with Middle Harbour to the south-west and Bantry Bay to the east, bordered by the bushland of Garigal National Park. It was originally part of Forestville and was developed from the 1950s, with LJ Hooker carrying out considerable development east of Starkey Street in the early 1960s, before the second Roseville Bridge opened in 1966. Starkey Street is the spine of the suburb, with Killarney Heights High School beside the oval and the primary school opposite. Most homes are owner-occupied family houses. Sandstone appears in retaining walls that level the sloping blocks, front steps and paths, driveway edging and paved terraces, and in natural rock along the bush edge.

The ridge drops away into wooded gullies on most sides, and that shapes how stone weathers here. Blocks backing onto the national park are shaded for much of the day and stay damp after rain, so black mould, green algae and moss grow readily on steps and wall faces, while lichen spreads across capping stones. Eucalypt leaves and bark fall year-round and leave brown tannin stains where they lie wet. Retaining walls built into the slope often show seepage lines and white mineral streaks. On homes from the 1960s, original sandstone paving and walls may have been pressure-washed or patched with cement over the years, which leaves uneven surfaces that hold dirt and growth more readily.

Planning controls for Killarney Heights still come from the Warringah LEP 2011, carried over when Warringah Council became part of Northern Beaches Council in 2016. On the council's own list of heritage-listed sites is the Bantry Bay Explosives Depot, a former explosives store on the water below, and the State Heritage Inventory records nearby places such as the Killarney Picnic Grounds and the Old Bullock Track. The residential streets are not, as far as we could establish, a conservation area, but an individual listing is still possible, so look at Schedule 5 before restoration. Rain falling on these streets reaches Middle Harbour within minutes, and NSW law makes it an offence to send anything but rain down those drains, so our run-off is collected.

Of all the Northern Beaches suburbs, Killarney Heights is among the nearest to Double Bay, about 25 to 35 minutes away depending on traffic over the Roseville Bridge or the Spit. That makes inspections and follow-up visits easy to fit in. Most homes have driveways and side access, though steep blocks may mean carrying equipment down to lower terraces. On properties that back onto the national park, we keep all products within the boundary, place bunding along the downhill edge and vacuum up wash water before it can run into the bush. Shaded terraces are usually cleaned on one visit and sealed on another, once a few dry days have passed and the stone has dried through.