Artificial Grass in Manly

Ten soil landscapes on one peninsula

Here is the whole list, taken from geometric intersection of the NSW soil landscape polygons with the Manly suburb boundary. Together these account for 98.0% of the polygon.

• Lambert, 37.4%. Hawkesbury Sandstone with rock outcrop over more than half the surface. Described as "seasonally perched watertables, shallow, highly permeable soil".
• Gymea, 17.0%. Sandstone again, "shallow highly permeable soil", "freely drained", "stable to slightly reactive".
• North Head, 15.0%. Named in the mapping. See the note below.
• Woy Woy, 9.4%. Beach ridges formed on marine sands, with "permanently high watertables" and a "Watertable at a depth of <200 cm".
• Newport, 6.1%. Wind-blown sand, free-draining, with "non-cohesive topsoils" and rated "Stable to slightly reactive".
• Watagan, 5.1%. Named in the mapping. See the note below.
• Narrabeen, 4.3%. Named in the mapping. See the note below.
• Disturbed Terrain, 2.6%. Artificial fill, poorly drained where it occurs.
• Warriewood, 1.1%. Named in the mapping. See the note below.
• Hawkesbury, 0.2%. Sandstone, "shallow, stony, highly permeable soil".

Now the note, because we would rather be straight with you than look better informed than we are. We hold the published per-unit descriptors for six of these ten: Lambert, Gymea, Woy Woy, Newport, Hawkesbury and Disturbed Terrain. We do not hold them for North Head, Watagan, Narrabeen or Warriewood, which between them cover about a quarter of the suburb. So we will name those four and give you their share of the map, and we will say nothing whatsoever about how they drain or how they behave under a base, because we do not have the source in front of us. Anyone who confidently tells you what the North Head unit does under a synthetic lawn is guessing.

Two further caveats that apply to every number above. These are whole-of-polygon figures at 1:100,000 scale, so they include the ocean beach reserve, the headland, the golf course, roads and the whole village core, not just residential back yards. And they describe Manly, not your address. Nobody, us included, can look at that table and tell you what is under your clothesline. A site check is the only way to know your block. If you are earlier in the process than that, the product side of fake grass is worth settling before the dirt is.

Perched water on the slope, standing water on the flat

Fragmentation on its own is just trivia. What makes it matter in Manly is that the two biggest awkward units contradict each other, and they are close enough to walk between in the time it takes a kettle to boil.

Start uphill. Lambert covers more of Manly than anything else, better than a third of the suburb, and it is sandstone country with outcrop across over half the surface. Its published description carries a phrase you rarely see: "seasonally perched watertables". Perched is the operative word. The soil above the rock is shallow and highly permeable, so rain sinks straight through it, reaches the sandstone, and then stops. For part of the year it sits there, a few hundred millimetres down, resting on stone, on a slope. Water in that position does not stay put. It moves sideways downhill along the rock surface, and it will happily travel through whatever you have built above it.

Now walk down to the flats behind the ocean beach. Woy Woy is old beach ridges built on marine sand. Its description is not "perched" but "permanently high watertables", with the water table logged at a depth of less than two metres. That is a different animal entirely. The sand drains beautifully in the top layer, so a downpour vanishes, but there is no downhill for it to vanish to, and the ground water underneath does not go away in September. Flat ground, sand, water below, year round.

Those two situations ask for opposite things from a base build. On the perched Lambert slopes the design problem is interception and grade. The excavation may reach rock earlier than budgeted, so the profile might be built up rather than dug down; falls need to be deliberate; and an installer may want to catch the lateral flow at the uphill edge so the crushed rock layer is not doubling as a stormwater channel for the block above. On the Woy Woy flats there is no fall to work with and no lower ground to send anything to, so the questions become the depth of the profile, whether the aggregate stays above the wet zone, where a discharge point legally exists, and whether a drainage line is needed simply because gravity is offering nothing. Same product, same suburb, genuinely different engineering. Our walkthrough of how a turf base is built, layer by layer sets out what those layers do and where the choices sit.

Between them sit the Gymea and Newport fractions, which are the easy ground: freely drained sandstone soil in one case, free-draining aeolian sand in the other, both rated stable to slightly reactive. Roughly a quarter of Manly is one of those two, and on that ground drainage largely sorts itself out and the money goes into levelling, compaction and edge detail instead. Worth saying plainly, though: free-draining is not the same as no water table. Woy Woy is highly permeable and has permanent ground water. Do not let anyone collapse those two ideas into one reassuring sentence.

For dog owners this is not an abstraction. Urine has to rinse through the backing and then get away through the base, and "away" means something different on a perched slope than on a flat block with water sitting under it. What changes in the specification, from backing to infill to the rinsing routine, is on our page about choosing turf for a household with dogs.

Getting materials onto a Manly block

Ask an installer what surprises them most about quoting on this peninsula and the answer will not be soil. It will be access.

An installed synthetic lawn is heavier than it looks, and almost none of that weight is the synthetic grass itself. The bulk is what goes underneath: excavated spoil coming out, then crushed rock and sand going in, tonnes of it on an ordinary back yard. On a flat block with a driveway, a bobcat and a tipper handle that in a morning. On a Manly slope block reached by a set of steps from the street, with a side path a wheelbarrow only just fits down, every one of those tonnes is moved by hand, twice. That is not a padded line item. It is genuinely more labour, and it will show in the rate.

Three things are worth checking before you invite anyone to quote. Whether a machine can physically reach the working area, or whether the job is barrow-only from the kerb. Where the spoil is going to be stockpiled, because a narrow Manly frontage often has nowhere legal to put a pile. And whether the street allows a truck to stand long enough to load out, which in the village core and the tighter streets behind it is a real constraint rather than a theoretical one.

The other distinctly local job type is small. Behind the Corso and through the older semis and terraces there are a lot of courtyards in the 15 to 40 square metre range, walled, shaded for part of the day, with drainage that has to work in a space where there is nowhere for water to go. Small does not mean easy, and it does not mean cheap per square metre either, for the barrow reasons above. It does mean the product decision gets simpler: on that footprint, stepping up a quality tier costs a few hundred dollars rather than a few thousand, on an artificial lawn you will be looking at from a kitchen window every day. If the space in question is a balcony or a rooftop terrace rather than ground you can dig, that is a different build with its own rules, and our guide to turf on Sydney apartment balconies and terraces is where to start instead.

Salt, wind and the verge question

Living on a peninsula with surf on one side and the harbour on the other means salt in the air most days and a solid onshore wind on many of them. Two honest points about that.

On salt, we are not going to tell you which product survives it best, because we cannot. There is no Australian testing data we can point to on how synthetic turf backings and infills perform under long-term salt exposure, and any supplier who tells you their grass is salt-proof is making a marketing claim rather than citing a study. What we will say is that backing type and infill choice are worth raising explicitly with whoever quotes you, that different products use different backing constructions, and that you are entitled to ask what the warranty says about coastal installations before you sign. A question you have asked and had answered in writing beats a claim you were told at the door.

On wind, the practical issue is mundane: sand, salt spray and windblown debris settle into the pile, and an exposed Manly yard collects more of it than a sheltered inland one. That is a rinsing and brushing rhythm, not a product defect. It is also an argument for making sure the perimeter is properly fixed, because loose edges on a windy aspect are how an artificial lawn starts lifting at a corner.

Which brings us to the strip out the front. Manly sits in Northern Beaches Council, and as at our last check the Council publishes no position at all on synthetic turf on nature strips, in either direction. We are stating that as a fact about what is published, not as a green light. That verge between your boundary and the kerb is council land, and silence is not permission. If you want to surface it, put the question to Northern Beaches Council directly and keep the answer in writing before anything is laid. Councils around Sydney have landed in very different places on this, from outright prohibition to formal approval processes to nothing at all, and we have collected the actual wording each one uses in our rundown of how Sydney councils have worded their verge positions. None of this has any bearing on your own front or back yard, which is your land and is not governed by nature strip rules.

What a Manly lawn is likely to cost

Published Australian supplier and industry figures give three indicative Sydney bands, and they are the same three everywhere in the city. Budget product lands around $75–95 per square metre installed, typically rated 5–8 years. Mid-range sits near $95–130 with a 10–15 year expectation. Premium starts around $130–160+ and is sold on 15–20+ years. Treat those as orientation, not a quote.

What varies in Manly is everything below the grass. Roughly speaking, about 40% of a job is materials, 30% is base preparation and 30% is labour, and this is a suburb that pushes on both of the last two. A perched-water slope block may need rock worked around and interception at the top edge. A flat block on the beach ridges may need a drainage line because there is simply nowhere for a fall to finish. A barrow-only site adds hours to every stage. An existing lawn has to be stripped and carted; a bare courtyard does not. That is why two Manly houses can receive genuinely different numbers for identical turf and both quotes be honest.

The single most useful thing you can insist on is an itemised quote: turf rate separated from excavation, from base material, from drainage, from disposal, from access allowance. It lets you compare like with like and it exposes the quote that was priced off a satellite image.

One correction we make on every page, because the myth will not die: there is no artificial turf rebate anywhere in Australia, from any council, state government or water utility. The water argument for synthetic grass is about a bill you no longer pay and a restriction you no longer have to work around. Sydney Water's permanent rules limit watering with drinking water to before 10am and after 4pm, with $220 fines for individuals, and drip systems are exempt. That is a real running cost saved. It is not a cheque from anyone.

Related reading

• A plain-language overview of fake grass for Sydney homes
• What each price band actually buys you
• Artificial grass in Chatswood, over the Spit on the lower north shore
• Synthetic turf in Ryde, inland on the shale ridges

Soil landscape data: Chapman G.A. and Murphy C.L., 1989, Soil Landscapes of the Sydney 1:100,000 Sheet, Soil Conservation Service of NSW (Map Ed. 4, 2009), NSW Department of Climate Change, Energy, the Environment and Water. Percentages describe the whole Manly suburb polygon, not any individual property.