How to install a Belgian block curb? Step-by-step for a lasting finish

Belgian block, also widely known as cobblestone, offers a distinctive blend of old-world charm, robust durability, and effective edge protection for driveways, walkways, and garden beds. Installing a Belgian block curb is a masonry project that, when done correctly, adds significant aesthetic value and structural integrity to your property for decades. While it requires precision and effort, this step-by-step guide will walk you through the process, ensuring a beautiful and lasting finish.

What is the Belgian block and why use it?

Belgian blocks are essentially large, rectangular pieces of natural stone, most commonly granite, cut to a generally uniform size. They are renowned for their strength and classic appearance.

• Natural Stone Durability: Primarily made from dense granite, Belgian blocks are incredibly strong and resistant to cracking, chipping, or deterioration from weather extremes, heavy traffic, and constant wear. They are built to last for generations.

• Distinctive Aesthetic: Their irregular yet uniform shape, coupled with the natural variations in granite colors (typically grays, blacks, tans, or subtle pinks), creates a timeless, rustic, and elegant look that synthetic materials cannot replicate.

• Edge Definition and Containment: As curbing, Belgian blocks provide a robust, permanent border that clearly defines spaces. For driveways, they prevent asphalt or gravel from crumbling or spreading at the edges. For garden beds, they contain soil and mulch.

• Versatility: While often used for curbs, their sturdy nature also makes them suitable for driveway aprons, border accents, and low retaining walls.

• Increased Property Value: The classic appeal and inherent durability of natural stone significantly enhance a property's curb appeal and market value.

  
  

Tools and materials needed

Before embarking on your Belgian block curb project, gather all the necessary tools and materials. Proper preparation ensures a smooth and successful installation.

Tools:

• Shovel: For excavation.

• Measuring Tape: For layout and precise measurements.

• Stakes and String Line: Essential for establishing straight lines and consistent heights.

• Rubber Mallet: For tapping blocks firmly into place.

• Long Level (4-6 feet): Crucial for ensuring blocks are level and at the correct grade.

• Trowel/Pointing Trowel: For applying and shaping mortar.

• Wheelbarrow: For mixing and transporting concrete/mortar.

• Plate Compactor (rentable): For compacting the sub-base (optional but highly recommended for heavier traffic areas).

• Safety Glasses and Gloves: For personal protection.

• Stiff Brush: For cleaning excess mortar.

• Grinder with Diamond Blade (optional): For making precise cuts if needed, though Belgian blocks are often laid as-is or with minimal cutting.

• Concrete Mixer (optional): For larger projects, renting one saves time and effort.

  
  

Materials:

• Belgian Blocks: Calculate the linear footage needed, adding 5-10% for cuts and potential breakage.

• Crushed Stone (Base Material): Typically 3/4-inch angular crushed stone for the primary base layer.

• Concrete Mix (Type S or M Mortar Mix, or specific concrete mix): For the footing and/or setting bed, depending on installation method. Consult local codes or professional advice.

• Masonry Sand or All-Purpose Sand: If using a sand setting bed (less common for driveway curbs due to stability).

• Water: For mixing concrete/mortar and curing.

• Polymeric Sand or Mortar: For filling the joints between blocks.

• Plastic Sheeting (optional): For covering curing concrete in hot weather.

  
  

Step-by-step installation guide

Proper installation is paramount for a lasting Belgian block curb. This guide focuses on a more robust installation method using a concrete footing, ideal for driveways and high-traffic areas.

Excavation and base preparation

1. Mark the Curb Line: Use stakes and a string line to accurately mark the intended path of your Belgian block curb. Ensure the line is straight or follows your desired curve precisely. Consider the width of the Belgian block plus a few inches on either side for the concrete footing.

2. Excavate the Trench: Dig a trench along the marked line. The depth will depend on the height of your Belgian block and the thickness of your base layers. A common depth is 8-12 inches:

   • 4-6 inches for compacted crushed stone base.

   • 4-6 inches for concrete footing/setting bed.

   • The top of the Belgian block should be slightly above the finished grade of the adjacent driveway/lawn for proper containment and aesthetics.

   • Ensure the bottom of the trench is level or follows your desired gentle slope for drainage. Remove all loose soil, rocks, and roots.

3. Compact the Sub-Base: Compact the exposed soil at the bottom of the trench thoroughly using a hand tamper or plate compactor. This creates a stable foundation and prevents future settling.

4. Install Crushed Stone Base: Spread a 4-6 inch layer of crushed stone into the trench. Rake it level, then compact it thoroughly using a plate compactor. This layer provides crucial drainage and additional stability.

   
   

Setting the blocks in mortar or concrete

For driveway curbing, setting blocks in concrete (either on a concrete footing or directly into a concrete bed) is highly recommended for stability and longevity.

1. Pour Concrete Footing: Mix concrete according to manufacturer instructions (or professional specifications). Pour a 4-6 inch thick concrete footing into the trench on top of the compacted crushed stone. Use your trowel to roughly level it.

2. Set the First Blocks: While the concrete is still wet, begin setting your Belgian blocks. Start at one end (or a corner).

   • Place each block firmly into the wet concrete.

   • Use a long level to ensure the block is perfectly level (front-to-back and side-to-side) and at the correct height relative to your string line.

   • Tap the block gently but firmly with a rubber mallet to seat it into the concrete until it's perfectly aligned.

3. Continue Setting Blocks: Work your way down the line, setting one block at a time.

   • Maintain consistent spacing between blocks (typically 1/4 to 1/2 inch). You can use small spacers if needed.

   • Continuously check alignment, level, and height with your string line and long level. Adjust by adding or removing concrete beneath the block, or tapping it.

4. Create a Concrete Haunch (Optional but Recommended): Once blocks are set, use a trowel to build up a concrete "haunch" or small support along the back side of the Belgian block, extending slightly up the side of the block. This provides additional lateral support and locks the blocks in place.

   
   

Finishing and sealing the curb

1. Allow Concrete to Cure: Let the concrete footing and haunch cure sufficiently. This typically takes 24-48 hours before walking on it, but full curing can take several days to a week, depending on the mix and weather. Keep the concrete moist during the initial curing phase, especially in hot, dry weather, by lightly misting it or covering it with plastic sheeting.

2. Jointing the Blocks (Filling Gaps):

   • With Mortar: Once the concrete is cured, mix mortar (Type S or N) to a stiff consistency. Use a pointing trowel to press the mortar firmly into the joints between the blocks. Smooth the joints for a neat appearance.

   • With Polymeric Sand (Less Common for Heavy-Duty Curbs): For a more permeable option (less common for high-traffic driveway curbs), sweep polymeric sand (a specialized sand that hardens when wet) into the joints. Use a stiff brush to work it deep into the gaps. Then, lightly mist with water to activate the polymers, following manufacturer instructions carefully.

3. Clean Up: Immediately clean any excess mortar or polymeric sand from the face of the Belgian blocks before it dries. A damp sponge or stiff brush works well.

4. Backfill: Once the mortar/sand in the joints has cured, backfill the trench alongside the curb with soil, gravel, or other desired landscaping material. Compact the backfill.

5. Optional Sealing: After the curb is fully cured and dry, you can apply a breathable masonry sealer. This is optional but can enhance color, protect against stains, and prolong the life of the mortar joints.

   
   

Maintenance tips for long-term performance

Belgian block curbs are exceptionally durable, but a little routine maintenance will ensure they remain beautiful and functional for decades.

• Inspect Joints Periodically: Regularly check the mortar or polymeric sand joints between the blocks for any cracking, crumbling, or erosion.

  • For Mortar Joints: If you find cracks or areas where mortar is loose, chip out the old, failing mortar and re-point with fresh mortar.

  • For Polymeric Sand Joints: If the sand erodes or cracks, sweep in more polymeric sand and reactivate it with water.

• Weed Control: Though generally resistant, weeds can sometimes sprout from seeds that settle in the joints. Pull them by hand or use a targeted herbicide.

• Clean as Needed: For general cleaning, a simple rinse with water and a stiff brush is usually sufficient. For stubborn stains (like moss, algae, or rust), use a mild masonry cleaner, following product instructions carefully. Avoid harsh acids unless specifically recommended for your stone type and applied by a professional, as they can damage both stone and mortar.

• Avoid High-Pressure Washing: While occasional light pressure washing is fine, avoid excessively high pressure or holding the nozzle too close, as this can erode mortar or polymeric sand joints.

• Address Adjacent Issues: Ensure that adjacent landscape elements (e.g., gravel from a driveway, soil from a garden bed) are well-contained and not constantly pressing against or spilling over the blocks, which could compromise their stability.

• Protect from De-Icers (if applicable): Some de-icing salts can be harsh on mortar joints. If using de-icers, choose calcium chloride-based products, which are generally less damaging than sodium chloride.

  
  

By following these installation and maintenance guidelines, your Belgian block curb will provide a sturdy, elegant, and timeless addition to your property for many years to come.