Uni-Pier® is Guaranteed in
any Corrosion Zone for 25 years.*

Many zinc coated steel products currently sold and used in Australia are not suitable for long term protection of structural steel in corrosive environments.

Home and building piers/stumps can rust within 6 years or less of being installed.

There are new Corrosion Zone Compliance Regulations that increase the minimum zinc corrosion protection for structural steel and piers/stumps.

Certifiers, engineers, designers and builders must design and build to comply with these new changes. This is good news, as it protects the structural steel components. The home owner can be assured his home will last longer than the Home Warranty period of 6-7 years.

Uni-Pier® products carry a Corrosion Zone Compliance label that makes it easy to select products that comply with any and all corrosion zones in Australia. All Uni-Pier® products are backed by 25-year Warranty against corrosion.

* C5 compliant only if the site structural engineer has designed the protective coating in accordance with all the relevant Australian Standards, BCA and NCC.

The Facts

If you are building within 10 kms of breaking surf, structural steel posts, piers, stumps, or columns must have a minimum zinc coating of 225 grams/m2 per side.
Certifiers, Structural Engineers, Building Designers and Builders must ensure that they design and build to comply with these new NCC regulations.
Certifiers will be required to determine the corrosivity category of the location of the new building works.
Builders will need to demonstrate that the works have been constructed in accordance to NCC regulations.
All Uni-Pier products are Batch Hot Dip Galvanised and can be used in C2, C3 & C4 corrosion zones.
Only Uni-Pier offers a complete range of zinc coated products starting at 390 grams/m2 per side and up to 600 grams/m2 per side as standard.

Corrosion Zones

Surf Seashore

C5 Compliant

0 - 200m +
from coastline

Consult with structural engineer for C5 compliance.

Breaking Surf

C4 Compliant

200m - 1km +
from coastline

C4 compliance requires a steel thickness of 3.5mm or greater


C3 Compliant

1km - 10km +
from coastline

All Uni-Pier products are C3 Compliant

Urban Inland

C2 Compliant

10km +
from coastline

All Uni-Pier products are C2 Compliant
Uni-Pier Corrosion Zone Guide
Ocean 200m 1km 10km Inland
Surf Seashore - C5 Zone Within 200 m of rough seas & surf beaches. May be extended inland by prevailing winds & local conditions.
Breaking Surf - C4 Zone From 200m to 1 km inland in areas with rough seas & surf. May be extended inland by prevailing winds & local conditions
Coastal - C3 Zone From 1 km to 10 km inland along ocean front areas with breaking surf & significant salt spray. May be extended inland to 50 km by prevailing winds & local conditions.
Urban Inland - C2 Zone Most areas of Australia at least 50 km from the coast. All Uni-Pier products
are C2 Compliant
C5 Corrosion Zone Rating rating
C5 Corrosion Zone Rating rating
C5 Corrosion Zone Rating rating
C5 Corrosion Zone Rating rating


Some of the most common questions about corrosion zone compliance

The changes are already in place, but become enforceable on the 1st May 2024.

The minimum zinc coating must be 225 grams per sqm per side. Only batch hot dip galvanised steel products can be used within 10km of breaking surf.

Uni-Pier products can be used in all corrosion zones.

Yes. But the cut faces must be repaired in accordance with the relevant Australian Standards. Refer to our 25 Year Warranty .

Yes. We need to stop the concrete getting inside the post. Plus most structural engineers require an anchor in the concrete.

Yes. Refer to our 25 Year Warranty.

It is important that our products are installed in accordance with out technical drawings and other technical specifications.

We recommend that the underside of the base plate be protected with an approved Duplex paint system. Refer to our 25 Year Warranty.

No. The posts must be 3.5mm or greater to comply with the minimum zinc coating requirements for C4 corrosion zones.

Call us on 1300 366 362. One of our technical team will assist you with your project.

Corrosion Zone Compliance

Don’t expose yourself.
Build on us.