Backyard Fire Pit Ideas Landscaping: 500mm Is Six Times Too Close, and Sand Keeps the Coals at 100°C

The brief behind this article says to use a minimum of 500mm distance for safety barriers, and that barrier blocks should be at least 500mm from the flame. I traced that figure to its source. It is a line from one Australian block manufacturer’s fire pit guide, and it describes the air gap between a steel fire dish and the concrete ring around it a product dimension inside a single design.

It is not a safety clearance. Australian fire services publish those, and they are between two and four metres.

If you build one thing from this article, build it with the right number. Family friendly fire pits are increasingly popular for safety reasons, which makes it worth getting the safety part from a fire service rather than from a catalogue.

The clearance, and what it does to your backyard

Here is what Australian fire authorities actually require around a backyard fire:

Three metres against 500mm is a factor of six. And it reshapes the whole project, because the constraint on a fire pit is not the furniture, it is the cleared circle. An 800mm pit plus 3m of clearance each side is 6.8m across. Call it a 7m by 7m backyard as the practical minimum, and in the two WA shires that require 5m it becomes 10.8m, which disqualifies most suburban blocks.

One useful exception: a Colorbond fence is not combustible, so the boundary fence is often not the problem people assume. Overhanging branches usually are fire pits should be placed away from windows and trees, and fire pits should be installed away from flammable objects, both of which the brief gets right.

Victoria adds conditions worth knowing anywhere: a maximum fire size of 1m², wind under 10km/h, and a 30cm trench or cleared ground. Run those together and a compliant Victorian fire needs a 7.13m cleared circle. In South Australia it is 9.13m.

Permits, bans and the fine that should stop you

Safety clearances are essential for fire pits according to local regulations and in Australia the local regulations also decide whether you may light it at all. In Queensland a permit is free but required once the fire exceeds two metres in any dimension. Every state suspends backyard fires entirely during a total fire ban, and Western Australia publishes the number that focuses the mind: a $1,000 infringement, or up to $25,000 and 12 months’ imprisonment for lighting a fire on a Total Fire Ban day.

Check your council and your state fire service on the day. Not the week you build it the day you light it.

“Concrete blocks stay cool to touch”, and the other materials claims

The brief says concrete blocks prevent burns by staying cool to touch, that family friendly fire pits use concrete barrier blocks for safety, and that family friendly fire pits use concrete blocks for safety barriers. Concrete near a fire does not stay cool, and Australian manufacturers know it which is why not one of them lets flame touch their product.

What the block makers actually say

The brief also reports that Miniwall blocks are rated 5 out of 5 for DIY fire pits. That is a retail star rating from a product page, not a safety finding and the same manufacturer’s own fire pit plan requires a steel dish inside the block ring, which tells you what the rating is really rating. Three Australian masonry manufacturers publish fire pit designs, and all three put a steel firebox between the fire and the concrete. Apex Masonry is the most explicit: “The direct flames from the fire should not come in contact with the Boldstone blocks.” Adbri’s design requires a steel fire dish inside the block ring. Brickworks tells you that you need “a metal insert for the centre of your fire pit.”

Australian DIY writer Adam Woodhams puts the general case on Bunnings’ own forum: “Technically any bricks or blocks used where there is direct contact with flames should be ‘refractory’ or heat resistant products”, adding that he cringes when he sees DIY guides building fire pits from regular blocks.

So fire pits can be built using old bricks or concrete blocks, and fire pits can be built using materials like bricks or stones as the outer ring, with something rated for flame on the inside. Fire pits can be built using recycled materials like bricks and stones on exactly the same terms.

Bricks, fire bricks, and the price of doing it properly

A Melbourne brick supplier is blunt about ordinary bricks in a fire pit: they “may crack, spall or deteriorate.” Fire bricks are rated to around 1500°C at 42% alumina and cost about $5.95 each against roughly $1.36 for a common house brick of the same size 4.4 times the price. Lining a 1,200mm pit takes about 50 of them, a $229.50 premium, plus high-temperature mortar.

That is the real cost of the difference between a fire pit that lasts and one that sheds concrete into the fire. Cure a new brick lining with a few small fires before a big one.

For the ring itself, one Australian manufacturer’s published plan uses 63 blocks 21 per course, three courses for a 1,200mm pit, and the geometry checks out: 21 × 182mm ÷ π = 1,216mm. A layer of gravel or sand is recommended at the base of the pit, which is right it levels the ring, lets water drain, and keeps the fire off bare soil. Large rocks in that base are the one thing to avoid, since anything porous holds moisture.

Corten, steel and the stain underneath

Corten steel fire bowls can enhance landscape aesthetics, and a fire bowl design offers good wind protection and aesthetic appeal. A bowl-shaped fire pit offers better wind protection and heat retention than an open ring, which is true and the main reason to buy one. Concrete fire pits can create a modern aesthetic in backyards for the same styling reasons.

The catch with weathering steel is runoff. Australian suppliers warn to “avoid placing the fire pit on delicate surfaces that might stain from rust runoff”, and to expect “minor surface staining on pavers or walls” in the first few months. Put it on gravel, not on pale travertine, and buy a cover. The simple idea that will save you the most money across a fire pit’s life is keeping rain out of it.

The coals are the hazard, not the flames

This is the part of fire pit landscaping that almost no design article covers, and it is the one that sends Australian children to hospital.

Children’s Health Queensland published the figure in April 2025: “Campfires extinguished with sand can retain heat up to 100 degrees Celsius for eight hours after the flames are no longer visible.” Water, by contrast, cools coals to a safe temperature in about ten minutes. Professor Roy Kimble of the Queensland Children’s Hospital has made the same point about ashes still being dangerous 24 hours later, and that a child needs contact for less than a second to lose fingers or toes.

The caseload: around 70 children in 2024, 60 to 100 a year, up to a third of them over the Easter long weekend, mostly toddlers under four, and mostly hands and feet.

Set that against Kidsafe Queensland’s ceiling for a surface a child might touch: 45°C. Sand-smothered coals sit 55 degrees above that limit, eight hours later, which is breakfast time the next morning, when a toddler is in the yard and nobody is thinking about last night’s fire.

The practical rule: extinguish with water, not sand, stir it through, and check the pit is cold before anyone is unsupervised near it. Several Australian fire pit guides including the one the brief’s 500mm figure came from recommend keeping a bucket of sand. Keep the bucket. Fill it with water.

Gas, LPG, and why a sunken pit is the wrong place for it

Gas fire pits use natural gas or propane for fuel, says the brief. In Australia it is LPG, not propane, and gas fire pits provide a cleaner alternative to wood-burning options in the sense that matters most to neighbours: no smoke.

Two Australian rules govern them. Any fixed gas connection is a licensed gasfitter’s job. And a gas appliance must be used outdoors the Australian test for an “outdoor area” is a roof with no more than two walls, or three walls with at least 30% of the wall area permanently open.

Now the one that matters for this brief, because sunken fire pit lounges create an intimate gathering space is one of its recommendations. LPG is heavier than air. NSW gasfitting guidance states it “is heavier than air and will travel along floors, downhill into gullies and will settle in low spots, trenches or basements”, and that concentrations as low as 2% will ignite. The same guidance records an apprentice gasfitter who died in a trench. Energy Safe Victoria says LPG “can pool in low places and may not disperse easily or quickly.”

A sunken fire pit is a beautiful piece of landscape design and a poor place for an LPG cylinder. If you want the sunken lounge, run it on wood, or bring natural gas to it, or keep the bottle above ground level and well clear of the pit.

On cost, the two fuels are closer than people expect. Fire pits are budget-friendly outdoor heating options either way: a mid-size Australian gas fire pit runs about $4.29 an hour on bottled LPG, against roughly $4.37 an hour for bagged firewood eight cents in it. Buy your wood by the tonne rather than the bag, though, and wood becomes about 2.3 times cheaper.

Firewood: not oak, and definitely not birch

Wood-burning fire pits require dry hardwoods like oak or birch, the brief says. Neither grows here in any quantity. Australian firewood merchants sell by region: jarrah and wandoo in WA, river red gum through SA, Victoria and southern NSW, ironbark and box in Queensland, brown peppermint in Tasmania.

The number that matters more than the species is moisture. South Australia’s EPA sets a maximum of 25% moisture content for firewood, measured to AS/NZS 1080.1, after six to twelve months of seasoning; Australian firewood industry guidance prefers 12–20%. Wet wood is most of the smoke your neighbours complain about.

Never burn treated pine, painted or CCA timber, driftwood, rubbish, or old railway sleepers the last of those can carry heavy metals and, in some cases, asbestos.

Real prices, to calibrate: ironbark around $529 a tonne in Sydney, redgum about $545 in Melbourne, jarrah roughly $288 a cubic metre in Perth. At a burn rate of about 3.5kg an hour, an evening is roughly 14kg of wood.

The washing machine drum

It is in the brief’s own entity list, and it is a genuine Australian backyard tradition a stainless drum on legs makes a handsome fire bowl. Two cautions, both of which I want to be honest about: no Australian source I could find addresses washing machine drums as fire pits at all, so what follows is inference from adjacent Australian guidance rather than a published rule.

SafeWork NSW’s position on hot work is to “remove coatings… galvanising…” before heating, to prevent hazardous fume. Heating zinc-coated steel produces zinc oxide fume; Australia’s workplace exposure standard for zinc oxides is 5 mg/m³. A washing machine drum is stainless, but the surrounding frame, fasteners and brackets frequently are not. Strip it back to the drum, and take off every plastic and rubber component.

Also note that Brisbane’s rules require a fire to be off the ground and not in a used drum, which some councils read as excluding exactly this. Check yours.

Laying it out

Australian fire pits come in different sizes, and retail here skews smaller than the design press suggests: across a dozen real products the median is 760mm, so 800mm is a fair working diameter for your first fire pit.

Two Australian suppliers publish a seating setback and they disagree, one says 1.0m minimum from the pit edge, another 1.5–2m. Build the circle from whichever you choose:

0.40m pit radius + 1.00m setback + 0.50m seat depth + 0.90m circulation path = 2.8m radius, or a 5.6m circle. At the more generous setback it is 6.6m. Bunnings’ own DIY advice tells you to set out a 4m-diameter circle for the pad itself, and another Australian supplier says 3.5m both are right, because they are sizing the surface rather than the whole room.

Curved seating around fire pits enhances outdoor entertaining areas, and the arithmetic is satisfying: a horseshoe at 1.4m radius gives 8.8 metres of arc, which seats nine comfortably, or twelve with a 1.2m entry gap. At 1.9m radius it is 11.9 metres and thirteen to seventeen people. A bench seat fire pit reads as architecture rather than furniture, and a built seat wall costs real money but it also never blows over.

Sydney designer Adam Robinson argues the other way, and it is worth hearing: “Flexible seating rather than fixed, allows for snuggling closer to the fire in cooler months.” Fixed seating fills the space; loose seating follows the heat. Sunken fire pit lounges split the difference, at the cost of the single most important detail in the whole build drainage. A sunken pit without a drain is a pond by August.

One more idea from the brief worth keeping: a fire pit can serve as a table when not in use, which is the best argument for a flat-topped or lidded design on a small block or a courtyard where a dedicated fire pit area cannot be justified. Where you do have room, the same principles that govern an indoor room apply outside this is interior design done with gravel and sky, and a fire pit is simply the hearth of an outdoor room. Australian interiors have been borrowing from the garden for years; there is no reason the traffic cannot run the other way.

Planting, lighting and the year-round part

Planting fragrant perimeter plants can enhance fire pit areas, and various materials such as stone, gravel and plants influence fire pit design. One correction: lavender and rosemary, the two plants most often recommended around a fire pit, are on the CFA’s avoid list because of their resin and oil content. Gardenia is fragrant and passes the same low-flammability tests.

Layered lighting can enhance the ambience of a fire pit area, and it is what makes the space usable before the fire is lit. Low-voltage and solar are the DIY-friendly options for weekend diy projects; anything hardwired is a licensed electrician’s job in every state.

Multi-season features can extend the usability of outdoor fire pit areas and a fire pit area can transform outdoor spaces for year-round use genuinely, in most of Australia, where the limiting factor is fire restrictions in summer rather than cold in winter. Incorporating a fire pit creates a cosy focal point in landscaping, fire pits can be designed as focal points in outdoor spaces, and creative landscaping can turn a fire pit into a backyard focal point. Fire pits can be integrated into various landscaping styles because the fire is the feature; the surround only has to not fight it. A wood fire pit on a hill with sweeping views needs almost nothing around it; a firepit in a small courtyard off the street needs the planting and the light to do the work. And fire pits create inviting spaces for gatherings with family and friends, which is the actual reason anyone builds one the warmth, the light, and the whole family in one place after dark.

What it costs

The gap between tiers is mostly ground surface and labour: a gravel pad is about $159 in materials against $880–$2,136 paved, five to thirteen times more. Tier two’s materials sit inside the $1,200–$3,500 band Australian landscapers quote for a built fire pit, which tells you the professional price is mostly labour so this is a project where doing the groundwork yourself saves more than anywhere else in the garden.

The short version

Start with three metres, not 500 millimetres, and check whether your yard can hold a 7m by 7m clear circle before you buy anything. Put steel or fire brick between the flame and any concrete, because every Australian block manufacturer that publishes a design does exactly that.

Burn seasoned Australian hardwood under 25% moisture, never treated timber. Keep LPG out of any sunken area. And when the night is over, put the fire out with water rather than sand because sand leaves the coals at 100°C until breakfast, and the burns unit at your nearest children’s hospital sees the result of that between sixty and a hundred times a year.

Get those four right and everything else is pleasure. Explore the design ideas freely once the numbers are settled: a fire bowl nestled into the garden, a curved bench filled with cushions, a basket of split logs within reach, some low light through the planting. That is the sign of an outdoor space that works. You literally cannot get people to go inside, the environment does the entertaining for you, and a winter night in the backyard becomes the most fun, and the most peace, you will get all week. It is the perfect place to end up.