Chainwire fence on concrete: installation methods explained
How are chainwire fence posts fixed into concrete?
A chainwire fence doesn’t need soil to go into the ground — on a slab, the post is either core drilled in, bolted to the surface with a base plate, or cast in at the pour. Whichever method is used, the slab itself now has to resist the load the surrounding soil would normally carry. Most commercial chainwire fence installations use one of these, or a combination.
Core drilling
A diamond core barrel cuts a clean hole (typically 100–150mm) through the slab. The chainwire fence post is plumbed and locked in with non-shrink grout or high-strength concrete.
Base plates
A steel plate welded to the post base is fixed to the slab surface with chemical or mechanical anchors. Recognised under AS 1725.1 as a standard fixing method for chainwire fence installations.
Cast in
Post sleeves, cast-in base plates, or the chainwire fence posts themselves are set in place before the concrete is poured — only possible if the fence is planned at the construction stage.
Is a concrete-mounted chainwire fence as strong as a traditional footing?
It depends on the method and the slab. For lateral load resistance, the honest ranking for a chainwire fence runs:
- Cast-in posts in a new slab
- Conventional in-ground footing
- Core drilled into an adequate slab
- Base plated to an adequate slab
A well-designed in-ground footing has depth on its side — a chainwire fence post set 600mm or more into the ground has a long lever arm and a large mass of soil and concrete resisting the moment. A base plate has only the slab’s thickness and the anchors’ pull-out capacity working for it. That doesn’t make base plates weak; it makes them appropriate for the right job. An internal storage-compound chainwire fence sees almost no wind load. A 3m external chainwire fence on an exposed hardstand yard does, and the fixing method needs to reflect that.
When it’s an engineering question, not a fencing one
AS 1725 chainwire fences aren’t deemed “structures” under AS 4100. For high wind loading, crowd control, safety barriers, or wherever public safety is at risk, the design also needs to comply with AS 1170, AS 4100 and AS/NZS 4600 — a tall fence base-plated to a slab in an exposed position should be engineered, not assumed. Tightening post spacing below the AS 1725 maximum of 3300mm is one of the simplest ways to reduce the load on each fixing.
What has to be checked before drilling or anchoring a chainwire fence
This is the step that separates a competent commercial chainwire fence installer from a problem. Cutting into a slab without knowing what’s in it can be expensive, dangerous, or both.
Post-tensioned slabs — no exceptions
Many modern car parks, podium decks and suspended slabs are post-tensioned. Cutting a tendon can cause sudden, violent failure and extremely costly structural repairs. A post-tensioned slab must be scanned before any chainwire fence core or anchor hole is drilled.
- Reinforcement — cutting rebar weakens the slab locally and blunts equipment; scanning locates it so fixings sit between bars.
- Waterproof membranes — penetrating a membrane on a basement ceiling, podium or rooftop creates leaks that surface months later. Sealed-anchor base plates are usually preferred for chainwire fence installations here.
- In-slab services — hydronic heating, conduit, drainage and data runs are all found inside slabs.
- Slab thickness and condition — thin, cracked, delaminated or poorly compacted slabs won’t hold anchors; a new thickened pad at each chainwire fence post may be the answer.
- Falls and drainage — fixing posts across a drainage fall can cause ponding or block flow paths.
- Strata and landlord approval — penetrating a slab on leased or strata property usually needs written sign-off before a chainwire fence goes in.
Non-destructive scanning — typically ground-penetrating radar — is standard practice on suspended and post-tensioned slabs, and should be priced into the chainwire fence installation rather than skipped.
Where is slab-mounted chainwire fencing used?
Inside buildings
A chainwire fence divides space without blocking light, airflow, sprinkler coverage or visibility, and it’s fast to reconfigure as a tenancy changes.
- Secure storage compounds and caged areas within a warehouse
- Tenant separation in multi-occupancy industrial buildings
- Tool, stock and high-value goods cages
- Plant room and switchboard enclosures, and machine guarding
- Basement car park storage cages and bay separation
- Bike and locker enclosures, bonded and quarantine stock areas
Outside, on hardstand and paved surfaces
- Loading docks and service yards separating vehicles from pedestrians
- Hardstand storage and container yards
- At-grade and suspended car parks, for perimeter control and bay separation
- Rooftop and podium plant areas on waterproofed decks
- Sports courts, with the chainwire fence fixed to the court surface or edge beam
- Utility compounds, data centres, substations and switchyards
- Airports and rail corridors, where paved surfaces and buried services rule out conventional footings
- Construction hoarding and temporary chainwire fencing, relocated as the site progresses
Does installing a chainwire fence on concrete increase costs?
Usually, though not always dramatically — and the cost drivers are different from an in-ground job.
What adds cost
- Core drilling, priced per hole — rates rise with diameter and slab thickness
- Slab scanning on suspended or post-tensioned structures
- Chemical anchors and engineered base plates
- Slurry containment and disposal from wet cutting
- Reinstatement and making good around penetrations
- Engineering design and certification on taller or exposed chainwire fence runs
- Restricted access, low headroom, after-hours work
What reduces cost
- No excavation, spoil removal or rock to deal with
- No footing concrete to supply and cure
- Faster install on straightforward base plate work
- No reinstatement of landscaping, paving or turf
- No waiting on footings before the chainwire fabric goes up
On a simple internal base-plate job over a sound slab, a chainwire fence can cost close to a conventional installation. On a suspended, post-tensioned, waterproofed deck requiring scanning, engineering and sealed penetrations, expect a meaningful premium. As with sloping sites, a site inspection is the only reliable way to price it.
Don’t forget the gate posts
A gate applies far more load to its posts than a run of chainwire fence does, and on a slab that load goes straight into the anchors. Gate posts on slab-mounted chainwire fences are routinely specified with larger base plates, more anchors, or core drilling — even where the rest of the run is base plated.
Need a chainwire fence installed on concrete in Sydney?
Longain Fencing installs chainwire fencing on slabs, hardstand, car parks, loading docks and internal warehouse floors across Sydney and NSW, for industrial operators, property managers, builders, councils and government clients. We assess the slab first, recommend core drilling or base plates based on what your chainwire fence actually has to do, and arrange scanning and engineering input where the structure demands it.
