Frenchs Forest sits on the plateau between Belrose, Forestville and Beacon Hill, with the hospital precinct at its centre and Garigal National Park on its fringes. The housing is overwhelmingly 1960s and 70s brick and tile on regular blocks with mature street trees.
The defining maintenance issue here is not salt or shade. It is that a whole suburb’s worth of concrete tile roofs is now fifty or sixty years old.
What happens to a concrete tile at fifty
Concrete roof tiles are manufactured with a surface coating that seals the concrete and provides the colour. That coating has a life, and on a 1960s roof it is long past it.
Once the surface has weathered away, the concrete underneath is exposed and porous. It absorbs water, stays damp longer, and becomes an excellent growing surface. That is why old concrete tile roofs grow moss and lichen so much faster than new ones.
The growth then makes it worse: lichen holds moisture against the tile and works its root structure into the surface, breaking it down further.
Why pressure blasting is the wrong answer
The instinct on a mossy fifty-year-old roof is to blast it clean. On a tile that has already lost its surface, high pressure removes more of what little is left and drives water under the laps and into the roof space.
It also moves tiles. An old tiled roof has brittle tiles and perished pointing at the ridge, and walking it carelessly cracks tiles that then leak.
The correct approach on a roof at this age is assessment first: is this a roof that should be cleaned and treated, or a roof that is at the end of its life and should be budgeted for replacement? Cleaning a roof that needs replacing is money spent twice. We will say so. More: roof cleaning and the jobs we turn down.
Ridge capping and pointing
On roofs of this era the mortar bedding and pointing along the ridges and hips has usually cracked and in places fallen out. That is a water entry path and a tile security issue, and it is visible during any roof inspection.
Worth knowing about before the next storm rather than after.
Face brick walls
The walls are generally unpainted face brick, which is durable and needs little, provided nobody takes a pressure washer to it. High pressure erodes mortar joints faster than brick and lets water into the wall. Soft washing removes algae and mould without touching the mortar. More: house washing.
Mature street trees
Frenchs Forest’s streets have substantial trees, which means real leaf load in gutters and roof valleys. Twice a year is the working standard, with a third check where canopy sits directly overhead. More: gutter cleaning.
Driveways and paths
Original concrete from the sixties, now heavily weathered, with moss on the shaded sections and oil staining at the carport. Moss returns each winter unless the shade or the drainage changes. More: moss on concrete.
A realistic schedule
Roof: annual inspection. On a sixty-year-old tile roof, assessment before cleaning.
Gutters and valleys: twice a year.
House wash: every two years, soft wash on face brick.
Driveway: annually where moss returns.
See our Frenchs Forest service page and the Northern Beaches overview.
