What is the best material to put under a brick walkway?

A beautiful brick walkway adds classic charm and value to any home. But what lies beneath those perfectly laid bricks is just as important as the bricks themselves. The base material, often out of sight, is the unsung hero that determines your walkway's stability, longevity, and ability to withstand the elements. Understanding what is the best material to put under a brick walkway is fundamental to ensuring your path remains beautiful, level, and safe for decades to come.

Why the base layer matters

Think of your walkway's base as its foundation – a skyscraper cannot stand without a strong, deep footing. For a brick walkway, the base layer serves several crucial functions:

• Load Distribution: It evenly distributes the weight of foot traffic and any other loads (like wheelbarrows or garden equipment) across a wider area, preventing individual bricks from sinking or shifting.

• Stability and Leveling: A properly prepared and compacted base provides a firm, level surface upon which the bricks can be laid precisely, preventing unevenness, dips, and wobbles.

• Drainage: It allows water to drain effectively through the walkway structure, preventing saturation of the subgrade (the natural soil underneath) and mitigating the damaging effects of freeze-thaw cycles.

• Weed Prevention: A well-constructed base, often coupled with a weed barrier, helps inhibit weed growth from pushing up through the joints.

• Freeze-Thaw Protection: By promoting drainage and acting as a buffer, the base minimizes the impact of water freezing and expanding beneath the bricks, which is a primary cause of cracking and heaving in colder climates.

  
  

Gravel vs. Sand vs. Stone dust

While these materials might seem similar, they each play distinct roles in a brick walkway's base system. It's usually a combination of them that provides the ideal foundation.

Crushed Stone (Gravel) – The Structural Base:

• What it is: Typically 3/4-inch angular crushed stone (like "compactable gravel," "road base," or "limestone base").

• Role: This is the primary structural layer. Its angular shape allows it to interlock when compacted, creating a very strong, stable, and permeable foundation. It's excellent for drainage.

• Why it's best: It's the most crucial component for load-bearing and preventing settling. A minimum of 4-6 inches (or more, depending on climate and traffic) is often recommended.

  
  

Bedding Sand – The Leveling Layer:

• What it is: Coarse, sharp, washed concrete sand (sometimes called "paver sand" or "C-33 sand"). It should be clean and free of excessive fines or clay.

• Role: Applied in a thin, uniform layer (typically 1 inch) over the compacted gravel base. It provides the precise bedding layer for the bricks, allowing for fine-tuning of their levelness and promoting interlock.

• Why it's best: It's granular enough to allow drainage but fine enough to create a smooth bed for the pavers.

  
  

Stone Dust (Screenings) – An Alternative Bedding Layer:

• What it is: A very fine byproduct of crushing stone, resembling coarse sand but with more angular particles and fines.

• Role: Can sometimes be used as a bedding layer instead of sand, especially in regions where it's locally available and economical. When compacted and wet, it can create a very firm bed.

• Considerations: Can become very hard when dry, making future adjustments difficult. Its fine particles can also impede drainage if not installed correctly. Many professionals still prefer concrete sand for bedding due to its consistent drainage properties.

  
  

How to prepare and compact the base

A robust base isn't just about the right materials; it's about proper preparation and compaction. This is where professional installation truly makes a difference.

1. Excavation: Dig out the pathway area to the required depth, accounting for the depth of your chosen bricks, the bedding layer (1 inch), and the gravel base (4-12 inches, depending on anticipated use and local climate/soil). Remove all organic material (grass, roots, topsoil).

2. Subgrade Preparation: The underlying soil (subgrade) should be firm and stable. Compact it thoroughly using a plate compactor. Ensure there's a slight slope (e.g., 1/4 inch per foot) for water runoff away from any structures.

3. Install Edging: Install a sturdy edge restraint (plastic, metal, or concrete curb) along the perimeter of the walkway. This prevents the base materials and bricks from shifting laterally.

4. Add Crushed Stone Base: Lay the crushed stone in lifts (layers of no more than 4 inches at a time).

5. Compaction: Crucially, compact each lift thoroughly with a vibratory plate compactor. This is the most important step for long-term stability. The base should be rock-hard.

6. Add Bedding Sand: Spread a consistent 1-inch layer of washed concrete sand over the compacted crushed stone. Do NOT compact this layer. Use screed boards to "screed" the sand, creating a perfectly level and uniform bed for your bricks.

   
   

Drainage and freeze-thaw considerations

Effective drainage is non-negotiable for a durable brick walkway, especially in climates with freezing temperatures.

• Permeable Layers: The use of crushed stone and coarse bedding sand allows water to quickly percolate down through the walkway and into the ground below, preventing it from pooling on the surface or saturating the base.

• Subgrade Sloping: The natural soil underneath the base should be sloped away from any adjacent structures (like your house foundation) to ensure that water draining through the base continues to move away.

• Geotextile Fabric: Some installations may include a layer of geotextile fabric between the excavated subgrade and the crushed stone base. This permeable fabric prevents the base material from mixing with the underlying soil, maintaining drainage efficiency and stability.

• Mitigating Freeze-Thaw: By allowing water to drain away quickly, a proper base minimizes the amount of water available to freeze and expand, thus protecting the bricks from frost heave and cracking.

  
  

Common mistakes to avoid during installation

Even with the right materials, common errors during installation can lead to premature failure of your brick walkway.

• Inadequate Excavation: Not digging deep enough to accommodate a sufficient base layer.

• Skipping Subgrade Compaction: If the natural soil underneath isn't compacted, it will settle over time, leading to an uneven walkway.

• Insufficient Base Thickness: A base that's too thin won't effectively distribute weight, leading to sinking and shifting bricks.

• Poor Base Compaction: This is perhaps the biggest mistake. If the crushed stone is not compacted in lifts until it's rock-solid, it will settle unevenly over time.

• Using the Wrong Sand: Fine, play sand or masonry sand retains too much water and can impede drainage, leading to issues. Use coarse, washed concrete sand for the bedding layer.

• Compacting the Bedding Sand: The bedding sand layer should not be compacted before laying bricks; it should be screeded (leveled) to allow the bricks to be tapped into place for a tight fit.

• Ignoring Drainage: Not ensuring proper slopes or installing a base that doesn't drain well will lead to water damage and frost heave.

• No Edge Restraints: Without proper edging, the bricks and base material will slowly spread outwards, causing the walkway to lose its shape and stability.

  
  

The beauty and longevity of your brick walkway are directly tied to the quality of its unseen foundation. Investing in the right materials and, crucially, proper preparation and compaction of the base layer ensures that your walkway will remain a charming and stable feature of your landscape for many years to come.

For the assurance of a flawlessly installed and enduring brick walkway, trust the expertise of Liberty Mason Work. Our experienced masons understand the science behind a stable base and apply meticulous techniques to ensure your pathway stands the test of time. Contact us today for a consultation and let us build the perfect foundation for your outdoor vision!