Anti-Dig Security Fencing: An Essential 2026 Australia Guide to Prevent Serious Perimeter Weaknesses

Anti-dig security fencing extends perimeter protection below ground to make it harder for a person or animal to create an opening beneath a fence. It is generally considered where a security assessment identifies digging, lifting the fence base or exploiting soft ground as a credible method of unauthorised access.

Not every commercial site needs below-ground protection. Adding it automatically can increase excavation, materials and installation costs without solving a real security problem. The decision should follow the risks associated with the property, assets and surrounding environment.

What Is Anti-Dig Security Fencing?

A standard fence primarily creates an above-ground barrier.

An anti-dig system continues that protection below or across the ground surface.

Depending on the project, this may involve:

• mesh extending vertically below ground

• buried welded mesh

• concrete plinths

• reinforced ground beams

• horizontal mesh aprons

• purpose-built underground barriers.

The appropriate method depends on what the perimeter needs to resist and what sits beneath the fence line.

When Is Below-Ground Protection Worth Considering?

Below-ground measures may be justified where the consequences of perimeter penetration are high.

Examples can include critical infrastructure, restricted compounds, secure storage areas and locations containing high-value equipment.

They can also make sense where the site's physical conditions make digging unusually easy.

Soft soil, loose fill or repeated erosion can create vulnerabilities that would not exist on a fence installed into hard ground or concrete.

A properly planned anti-dig security fencing system addresses those site-specific vulnerabilities rather than using a standard underground detail everywhere.

Consider the Threat Before Choosing the Depth

There is no universal burial depth suitable for every secure perimeter. The correct detail depends on the threat being managed, soil conditions, fence system and any project-specific security requirements.

This is particularly important for government work.

Australian Government entities operate under the Protective Security Policy Framework, which requires protective security to be managed according to applicable risks and requirements rather than relying on one generic physical measure for every facility.

For a tendered project, follow the approved security specification and relevant technical documentation.

Underground Services Can Change the Design

Before excavating beneath a fence line, you need to understand what is already in the ground.

Commercial boundaries can contain:

• electrical cables

• water services

• telecommunications

• stormwater pipes

• sewer infrastructure

• irrigation

• fire services.

  
  

Deep anti-dig measures may conflict with these assets. Service locating and project drawings should therefore form part of installation planning where excavation is required. If deep excavation is unsuitable, an alternative arrangement may need to be considered by the project designer.

Concrete Is Not Always the Only Answer

People often assume below-ground security requires a continuous concrete footing.

That can be appropriate in some applications, but it is not the only option.

Mesh can sometimes extend beneath the surface or form an underground apron. These systems can reduce excavation compared with a continuous concrete element.

Concrete may provide a more substantial physical boundary but can also affect drainage and increase civil work.

The choice should reflect actual security requirements rather than simply selecting the heaviest construction.

Drainage Needs Careful Attention

Water still needs somewhere to go after the fence is installed.

A continuous underground barrier can alter natural surface and subsurface drainage.

This matters particularly on sloping commercial sites, around swales and near stormwater systems.

Poor drainage planning can contribute to erosion, ponding or deterioration around the fence line.

When anti-dig security fencing crosses a drainage path, the drainage design and perimeter design need to work together.

How Anti-Dig Protection Works With Gates

Vehicle and pedestrian gates need separate consideration because the ground beneath a moving gate cannot always be treated in the same way as fixed fence sections.

Potential weak points can occur:

• beneath gate leaves

• beside gate posts

• around sliding gate run-back areas

• beside tracks

• where pavement meets unsealed ground.

  
  

The surface underneath a vehicle gate may already be concrete, which can provide a substantial barrier.

Where the surface is unsealed, another approved treatment may be necessary.

Gate clearances should still allow safe, reliable operation.

Animal Control Can Be Another Reason

Below-ground protection is not limited to human intrusion.

Some sites may need to prevent animals from digging into or out of a controlled area.

The required detail may differ significantly from a system intended to resist deliberate human intrusion.

This distinction should be made clear in the specification.

If the primary issue is wildlife or domestic animals rather than security intrusion, the fence can often be designed specifically around that problem.

Inspection After Installation Matters

Much of an anti-dig system disappears once the trench is backfilled.

That makes staged inspection valuable.

Before covering the work, the project team may need to verify:

1. depth and position

2. overlap between sections

3. connections to the main fence

4. treatment around posts

5. gate transitions

6. drainage interfaces

7. specified materials.

   
   

Photographic records can also support the project handover where required.

When to Call a Professional

You should involve a commercial security fencing contractor when below-ground protection must integrate with high-security mesh, gates, concrete structures, drainage or existing underground services.

Colemans Fencing can assess the practical installation requirements of anti-dig security fencing and identify sections where the proposed detail may conflict with site conditions.

Security or engineering consultants should determine specialist performance requirements where these form part of the project's formal design.

Conclusion

Below-ground protection is useful when the base of the fence represents a genuine perimeter vulnerability.

The best solution may involve buried mesh, an apron, concrete or another approved barrier depending on the threat and site.

Do not specify anti-dig security fencing solely because it sounds more secure. Define the risk first, investigate ground conditions and coordinate the detail with services and drainage.

Colemans Fencing can assist with practical planning for Australian commercial perimeter fencing where below-ground protection forms part of the approved scope.

FAQs

Does every security fence need anti-dig protection?

No. It should generally be used where the project's risk assessment or security specification identifies below-ground access as a concern.

Can anti-dig mesh be added to an existing fence?

Sometimes. Suitability depends on the existing fence construction, access for excavation, underground services and required security performance.

Can concrete be used beneath security fencing?

Yes. Concrete plinths or ground beams can be used in suitable designs, but drainage and existing services need consideration.

Should anti-dig protection continue beneath gates?

The gate area needs to achieve the required perimeter security, but the solution may differ from fixed fence sections because the gate must operate freely.