Retaining Wall Post Spacing Calculator

If you’re a DIY builder tackling a wall project in the backyard or a professional home building contractor, it’s essential to understand the wall post spacing.  During retaining wall construction spacing of the wall posts is the critical factor which saves homeowners and businesses from costs of wall post repairs and reinstallation in the future. A proper retaining wall post spacing ensures your installation is long lasting, stable and does not fail easily.

At Austrina Steels, we've seen countless retaining walls fail due to one simple mistake that’s incorrect post spacing. The guide is here to help homeowners and contractors understand everything you need to know about calculating the right distance between posts, and why using a wall post spacing calculator is essential for your building project.

What is Retaining Wall Post Spacing and why does it matters?

Retaining Wall Post Spacing means the distance between vertical support posts in the retaining wall system. The wall post whether timber, concrete or steel is the spine or backbone of your wall that fixes your wall to the ground for structural support. The wall post provides structural support and prevents the wall from problems caused by soil and water pressure.

Think of posts as soldiers standing in formation. Place them too far apart, and the wall panels between them will bow down, crack, or collapse under pressure. Position them correctly, and your wall will withstand decades of soil pressure, weather extremes, and load variations.

Why’s a retaining wall post spacing calculator required?

A retaining wall post spacing calculator is a specialized tool that helps contractors and DIY home builders like you determine optimal spacing based on wall specifications, soil conditions, and material properties. These calculators eliminate guesswork and provide accurate measurements that comply with Australian building standards and engineering requirements. Additionally, the proper use of a post spacing calculator helps build walls that last long and handle pressure.

Always make sure you use to post spacing calculators with Key Components like:

• Wall height and total length.

• Multiple Post material (steel H-posts and C-posts, or timber or concrete) options

• Soil type and drainage conditions according to geography of the area.

• Expected load requirements.

• Local environmental factors and government building guidelines standards.

• Retaining wall post depth calculations.

Why Incorrect Post Spacing Causes Retaining Wall Failure?

Retaining wall failure isn't just an inconvenience, it's often a serious safety hazard which can cause property damages, injure people, and result in expensive court litigations and fines. Some of the common causes of failure of walls are:

• Excessive Lateral Load: When your wall posts distances are spaced too far apart, the horizontal pressure from retained soil is not distributed properly causing failure from excessive lateral load. The wall panels or sleepers between posts end up bearing loads they aren’t designed to handle, leading to bowing of the wall, its cracking, and ultimately collapse.

• Compromised Load Bearing Capacity: At Austrina Steels, we want you to understand that a post has a specific load bearing capacity based on its material, depth, and soil conditions. Spacing these steel posts or wood posts beyond design capacity overloads individual posts, causing them to lean, crack, or come out of the ground entirely.

• Progressive Failure: A retaining wall failure rarely happens all at once. It starts with one weak point, often where posts are too widely placed. As one section fails, other sections bear higher pressure load, creating a domino effect which brings down the entire wall.

• Water Damage Acceleration: Improper spacing of posts creates flexing points where water penetrates easily. Combined with inadequate drainage, the penetrating water accelerates corrosion of poorly maintained steel posts causing collapse of the wall. 

Basic wall post spacing guidelines

Each project you as a homeowner or contractor owner take while building a wall requires a different post spacing requirement. However general Retaining Wall Post Spacing Calculator guidelines to start your wall project can be following: 

• Small walls (less than 0.8 m high):  You should space the posts about 1–1.5 m apart.

• Medium walls (Between 0.8 – 1.5 m high): Posts in your wall project need to be spaced 1.5 to 2.0 m apart.

• Larger walls (Between 1.5 – 2.4 m high): Posts spaces need to be between 1.8 to 2.4 m apart, for engineered design with wall above height of  2.4 m.

We at Austrina steels advise our clients to space Galvanised Steel Posts from Austrina steels  with these basic outline:

Conclusion

Proper retaining wall post spacing  designed with use of  Retaining Wall Post Spacing Calculator and professional engineer lasts longer. Hence, use the calculator to check the local Australian building standards, review the soil and water retention to install your wall if you are a home owner building a backyard wall project.  If you are completely new to building, Austrina Steels recommend you seek engineers and contractors help for proper post spacing.