Concrete for Retaining Wall Post Footings

Concrete for Retaining Wall Post Footings

Every steel retaining wall post needs to be set in concrete footings — and getting the concrete specification right is as important as getting the post size right. Undersized or poorly mixed footings are one of the leading causes of post movement and wall lean over time.

We supply 20MPa concrete mix for retaining wall post footings in two formats — bags for small projects and top-up quantities, and by the cubic metre for larger jobs where ordering in bulk is more economical.

How Much Concrete Do You Need?

Each post footing typically requires 0.05–0.12m³ of concrete depending on post size and wall height. Use our WallWise Pro calculator to get an accurate concrete volume for your wall. As a rough guide:

• 100 Series post — approx. 0.05m³ per footing (300mm diameter × 600mm deep)
• 150 Series post — approx. 0.08m³ per footing (350mm diameter × 750mm deep)
• 200 Series post — approx. 0.12m³ per footing (400mm diameter × 900mm deep)

Specification

• Minimum 20MPa compressive strength for all post footings
• Allow 24–48 hours minimum cure before backfilling and loading the wall
• For walls over 1.0m or on reactive clay: consult a structural engineer for footing design

Pair with galvanised steel posts and our retaining wall kits.