How to Build a Railway Sleeper Retaining Wall

Learn how to build a strong, long-lasting railway sleeper retaining wall. This guide covers materials, layout, drainage, and installation tips for garden projects using oak, softwood, or reclaimed sleepers.

Why Choose Railway Sleepers for Retaining Walls

Railway sleepers are one of the most durable and attractive ways to retain soil or create raised levels in your garden.
They’re strong, versatile, and natural-looking — perfect for borders, terraces, raised beds, or tiered landscapes.

Treated Softwood Railway Sleeper

Oak Railway Sleeper Landscaping Grade 2.4m

Rustic Reclaimed Railway Sleeper 2.6m

Hex Head Timber Screws for Railway Sleepers

At Clarke Fencing, we stock a full range of oak sleepers, softwood sleepers, and reclaimed sleepers

What You’ll Need

• Railway sleepers – softwood, oak, or reclaimed

• Postcrete or concrete mix for posts

• Wooden fence posts (if using vertical supports)

• Gravel and aggregates for base and drainage

• Weed control membrane

• Sleeper pins (ground spikes) for reinforcement

• Hex head timber screws (heavy-duty landscape screws)

• Sleeper joining plates and L-brackets for corner and layer connections

Railway Sleeper Pin for Single Sleeper Galvanised

Railway Sleeping Joining Bracket Galvanised

Step-by-Step: How to Build a Sleeper Retaining Wall

Step 1: Plan and Measure Your Wall

Before you start digging, mark out the wall’s position using string and pegs.

• For walls under 1m high, horizontal stacking is usually sufficient.

• For walls over 1m, include vertical posts or reinforced sleeper pins to handle soil pressure.

Take time to measure accurately and check levels — small adjustments now will save major headaches later.

Step 2: Prepare the Base

Dig a trench along your marked line:

• Depth: around 150–200mm

• Width: slightly wider than your sleepers

Add a 100mm layer of compacted gravel or hardcore for a stable, free-draining base.
This stops the sleepers from sitting in water and helps prevent shifting over time.

Step 3: Install Support Posts or Sleeper Pins

For taller or load-bearing retaining walls, reinforcement is essential.

Option 1: Vertical Posts

• Space posts roughly 1.2–1.5m apart.

• Set them 600mm deep in holes filled with Postcrete or concrete.

• Align perfectly vertical and allow 24 hours to cure before fixing sleepers.

Option 2: Sleeper Pins (Ground Spikes)

For shorter walls (under 1m), use sleeper pins instead of posts.

• Hammer galvanised steel pins behind or through the sleepers.

• Secure them with screws or bolts to the timber.

• These pins provide excellent hidden strength while maintaining a clean front face.

Railway Sleeper Pin Double Sleeper Galvanised

Both options resist soil pressure and keep the wall upright and secure over time.

Step 4: Lay the First Row of Sleepers

Lay your first sleepers along the prepared base.
Check each one with a spirit level both front-to-back and side-to-side.

If your wall follows a curve, angle the sleepers slightly at the ends to create a smooth line.
Once positioned correctly, use your rubber mallet to tap them tightly together.

Step 5: Fix Sleepers Securely Together

Stack the next row of sleepers, staggering the joins like brickwork for extra strength.

Hex Head Timber Screws

Use hex head timber screws to fasten sleepers together.

• Choose screws 150–250mm long.

• Drive directly through sleepers using an impact driver — no need for pre-drilling in most cases.

• Galvanised or green-coated screws resist rust and blend well with treated timber.

These heavy-duty screws are ideal for joining layers, securing corners, or fixing sleepers to support posts.

Joining Plates and L-Brackets

Add sleeper joining plates to reinforce straight joins and L-brackets for corners.

• Fix plates on the back face to hide them from view.

• Use galvanised screws for outdoor durability.

• They help prevent twisting, separating, or movement over time.

Sleeper Pins for Additional Strength

For maximum stability, combine sleeper pins with screws and brackets — especially if your wall retains soil or sits on a slope. The pins hold the wall in place, while the screws and brackets bind it tightly together.

Step 6: Add Drainage and Backfill

Behind the wall, lay a strip of weed membrane and add 100mm of drainage gravel or shingle.
This stops soil pushing through the gaps and allows water to flow freely.

Weed Check Ultra | Weed Membrane Rolls

20mm Shingle | 25kg Mini Bag

For taller retaining walls, install a perforated land drain pipe at the base and lead it to a safe outlet — this prevents water pressure from building up behind the wall.

Backfill gradually in layers, compacting the soil lightly as you go.

Step 7: Finishing Touches

Once the wall is built and filled, check everything is level and secure.

You can then:

• Trim any exposed posts or pins flush with the sleepers.

• Apply a decking oil or wood preservative to protect the timber and enhance its colour.

• Cap the top with a decorative sleeper layer for a neat, professional finish.

• Add lighting or planting pockets to soften the look and highlight your work.

Recommended Sleeper Options

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Jason Clarke

Ask them a question by emailing [email protected]

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