What size is a standard UK garden sleeper?

The most common size is 2.4 metres long, 200mm wide, and 100mm thick. You can also find 1.2m lengths and thicker 'heavy duty' 125mm sleepers.

Which is better: horizontal or vertical sleepers?

Horizontal stacking is faster and easier for low straight walls. Vertical (soldier) placement is ideal for curved walls and allows for more flexible height transitions, but requires deeper digging for each sleeper.

Do I need to treat the sleepers?

Most modern sleepers are pressure-treated (Tanalised) to resist rot. However, if you cut them, you MUST apply an end-grain preservative to the cut surface to maintain the protection.

How deep should I bury vertical sleepers?

For a sturdy retaining wall, at least one-third (1/3) of the total length of the sleeper should be buried underground and set in concrete or well-compacted hardcore.

What size is a standard UK garden sleeper?

The most common size is 2.4 metres long, 200mm wide, and 100mm thick. You can also find 1.2m lengths and thicker 'heavy duty' 125mm sleepers.

Which is better: horizontal or vertical sleepers?

Horizontal stacking is faster and easier for low straight walls. Vertical (soldier) placement is ideal for curved walls and allows for more flexible height transitions, but requires deeper digging for each sleeper.

Do I need to treat the sleepers?

Most modern sleepers are pressure-treated (Tanalised) to resist rot. However, if you cut them, you MUST apply an end-grain preservative to the cut surface to maintain the protection.

How deep should I bury vertical sleepers?

For a sturdy retaining wall, at least one-third (1/3) of the total length of the sleeper should be buried underground and set in concrete or well-compacted hardcore.

Sleeper Wall Estimator

Calculate timber quantities for your garden landscaping project.

Wall Length (m)

Visible Height (m)

Laying Method

* Calculation based on standard UK garden sleepers (2.4m x 200mm x 100mm).

Material Estimate

Stability Note: For walls over 0.8m high, we recommend using structural steel UC-beams as uprights or consulting a structural engineer. Always use **stainless steel landscaping screws** to prevent corrosion.

Building with Sleepers: The UK Guide

Professional Finish

Timber sleepers are a versatile and cost-effective way to create tiered gardens, raised beds, and retaining walls in the UK. They offer a natural aesthetic that blends perfectly with lawns and plants.

When building a retaining wall, the most important factor is **drainage** and **structural stability**. Soil is heavy, especially when wet, and it will exert significant pressure on your wall.

Material Checklist

New Softwood (Pine)Lighter / Cheaper

New Oak (Hardwood)Heavy / Long Life

Reclaimed (Creosote)Hazardous / Avoid

Fixing & Fastening

For horizontal walls, we recommend using **'Landscape Screws'** or **'Timber Drive'** screws. These are heavy-duty, self-countersinking screws that don't require pre-drilling and provide immense holding power.

Overlap your sleepers like bricks (staggered joints) to ensure the wall doesn't have a weak vertical line that soil pressure could push through.

Pro Tip: Drainage is Key

Always backfill the space between the soil and the sleepers with **10-20mm shingle or gravel**, and use a perforated drainage pipe at the base. This prevents hydrostatic pressure from building up and potentially collapsing your wall during heavy rain.

Sleeper Wall FAQ

Safety & Planning

If your retaining wall is over **1.0m high**, or if it is supporting a driveway or building, you must consult a structural engineer and you may require Planning Permission. This calculator is for decorative garden walls up to 1.0m high.