Adding a cobblestone paver edging along an asphalt driveway is an elegant way to define the driveway while complementing the look of both the pavement and the landscaping. A cobblestone border prevents erosion at the edges of the asphalt, clearly delineates the boundaries of the driveway, and provides visual interest. With proper base preparation and installation techniques, a cobblestone edge can last for decades.
Benefits of Using Cobblestone Edging
Cobblestone offers numerous advantages as an edging material:
- Aesthetic appeal – The charming, rustic look of cobblestones complements both traditional and contemporary landscaping styles. Their organic shapes provide visual interest.
- Durability – Cobblestones can last 50 years or longer. Their strength withstands weather, vehicles, and ground movement better than other edging options.
- Versatility – Cobblestone comes in a variety of colors and can be installed in different patterns to suit your tastes. They pair well with asphalt, concrete, gravel, soil, grass, and mulched beds.
- Value – Quality cobblestones are a sound investment that can significantly increase your home’s curb appeal and resale value. Their longevity offsets the higher initial cost.
- Low maintenance – Once installed properly, cobblestone borders require little upkeep other than occasional weeding between stones. No painting or staining is needed.
Planning Your Cobblestone Edging
Careful planning ensures your cobblestone edging will complement your driveway and landscape design for years to come.
Choose Cobblestone Type
Cobblestones come in several natural stone varieties:
- Granite: Extremely hard and durable. Colors range from gray to pink and red. Provides a formal, elegant look.
- Limestone: Off-white to light gray. Weathers naturally for an aged, antique appearance.
- Basalt: Dark charcoal hues. Hardness varies. Provides nice contrast against light asphalt.
- Quartzite: Grays, blacks, browns. Very dense and resistant to weathering.
- River rock: Smooth, rounded appearance. Mix of earth tones. Informal, natural look.
Consider the style of your home, color of your asphalt, and surrounding landscaping. View cobblestone samples on-site if possible.
Determine Cobble Size
Cobblestones range from 2 inches to 12 inches across their longest dimension.
- Smaller cobblestones (2-4″): Good for short driveway borders and tight curves. Provide more delicate, intricate patterns. Require more stones per linear foot.
- Medium stones (4-8″): Versatile size for most edging projects. Easier to handle and install neatly than large stones.
- Large cobblestones (8-12″): Make a dramatic statement for longer driveways. Limit use on tight corners. Harder to cut precisely.
Choose a size in proportion to your driveway’s width. Opt for large stones on wide driveways and smaller ones on narrower paths. Mixing sizes can add visual interest too.
Calculate Material Needs
Measure the linear footage around the driveway’s edge to determine how much cobblestone you’ll need. Multiply this length by the recommended width of your planned edging, generally 6-12 inches.
Then factor in:
- 10-15% extra for wastage and imperfections
- Base material (gravel and sand)
- Mortar or polymer adhesive
- Landscape fabric
- Edge restraints (if needed)
Having extra cobbles is better than running short. You can return unused stone.
Choose Installation Pattern
Attractive patterns add personality to your cobblestone edge. Popular options include:
- Running bond: Cobblestones in even horizontal rows. Provides clean, uniform look. Beginners should start with this simplest pattern.
- Herringbone: Cobblestones set in a V-shape for a classic, timeless edge. Eliminates straight mortar joints.
- Random: Informal pattern with cobblestones placed in uneven rows. Creates a lush, natural appearance resembling paths through wooded areas.
- Mosaic or patchwork: Cobblestones deliberately arranged by color and size to make geometric shapes. Requires some cutting for precision.
- Spiral: Cobblestones radiate outwards from a center point like a pinwheel. Achieves a focal point.
Dry lay your cobbles on the gravel base first to visualize the pattern.
Choose Mortar or Adhesive
Cobblestones can be set into mortar or bonded with a flexible polymer adhesive:
Mortar provides time-tested strength but allows little flexibility. Use for formal edges set in a running bond or herringbone pattern. Require precise installation.
Adhesive allows stones to move independently, preventing cracks. Good for curved borders and organic patterns. More forgiving for DIYers. Use special polymeric sand made for wide joints.
See the installation steps below for how to use each material properly.
Preparing the Base
Proper base preparation prevents your cobblestone edge from sinking or shifting out of alignment over time.
Remove Existing Edging
If replacing an old landscape border, take it out entirely. Dig down at least 6 inches below the previous edging to remove old roots or unstable soil.
Excavate Space for Base
Excavate a trench 12-16 inches wide and 6-8 inches deep along the driveway’s edge. Slope the soil inward so water drains under the driveway.
Dispose of excavated material unless it’s good topsoil, which can be saved for later landscaping use.
Add Gravel Base Layer
Fill the excavated area with 4-6 inches of packed gravel (smaller stones no larger than 3/4 inch). Compact the gravel thoroughly with a plate compactor.
The gravel consolidates the soil beneath and facilitates drainage under the cobblestones.
Install Landscape Fabric
Line the gravel base with landscape fabric to prevent weeds from emerging between the cobblestones later. Overlap edges 6-12 inches. The fabric also keeps the sand setting bed from migrating into the gravel below.
Add Sand Setting Bed
Spread 1-2 inches of coarse concrete sand over the fabric. Screed with a straight 2×4 to smooth it evenly. Mist lightly with water before setting cobblestones to prevent the dry sand from sucking moisture out of the mortar.
Installing Cobblestone Edging
Once your gravel base is prepped, you’re ready to set the cobblestones using your chosen mortar or adhesive method.
Mortared Cobblestone Edge
Mortar provides time-tested strength for formal cobblestone patterns but allows little flexibility. Mortared edging often cracks unless the base is extremely stable. Use these steps for a mortared installation:
1. Prepare mortar
Mix polymer-modified mortar adhering to the manufacturer’s directions. Traditional types like M or S mortar can also be used. Add mortar color if desired.
The mortar should be firm enough to handle but still sticky, like a thick peanut butter. Add water or polymer as needed to adjust the consistency.
2. Dampen the sand bed
Mist the sand bed lightly before placing any stones. This keeps the dry sand from drawing moisture out of the fresh mortar.
3. Set the first course
Starting at an edge or corner, set the first row of cobblestones 1/2 to 1 inch above the final planned height. Push them firmly into the sand for stability. Allow 1/4 to 1/2 inch gaps between stones for mortar and grout.
Use spacers cut from 1/2 inch PVC pipe to ensure even spacing.
4. Fill joints with mortar
Butter the sides of each stone with mortar using a trowel. Firmly press the next cobblestone into place, squeezing the mortar tight into the joint. Remove excess squeeze-out promptly.
Strike flush any mortar protruding above the cobblestones using a trowel edge. Don’t smear mortar onto the surface.
5. Check alignment frequently
Every few feet, place a level along the stones to ensure they align properly and remain even as you build the edge course-by-course. Make minor adjustments quickly before the mortar hardens.
6. Allow mortar to set
Let the initial few courses sit undisturbed for about 30 minutes. Then continue building up the border to full height in similar fashion. Again let mortar set 30 minutes before proceeding.
7. Final leveling
Once the mortar has hardened enough to resist minor movement, remove the 1/2 inch spacers and use a rubber mallet to tap the edging down to final level. Fill remaining voids with fresh mortar.
8. Let mortar cure
Leave the edging undisturbed for 2-3 days to fully cure before grouting or exposing to traffic. Keep the mortar moist if needed to prevent cracking while curing.
9. Grout joints
Sweep polymeric sand formulated for wide joints into the 1/4-1/2 inch gaps between stones. Mist lightly with water to activate the bonding agent, then allow to fully cure before exposure to traffic.
Polymeric sand resists erosion better than plain cement grout in wider joints.
Adhered Cobblestone Edging
Flexible adhesive bonding allows subtle movement, preventing cracks in organic patterns and curved borders. Use these steps:
1. Dry lay stones
Lay cobblestones in your planned pattern on the prepared sand bed without any adhesive. Make adjustments until you achieve the desired look.
2. Mark footprint
Outline each stone’s position with marking paint or a stick. Remove the cobbles once marked.
3. Apply adhesive
Following the manufacturer’s directions, apply a zig-zag bead of landscape block adhesive along the center of each cobble’s footprint on the sand bed.
4. Replace marked stones
Firmly press each marked cobblestone back into place, seated in the adhesive according to its outline.
5. Fill gaps wider than 1/2 inch
For sizable gaps between stones, insert backer rod into the joint then apply adhesive into the void around it. This prevents adhesive waste.
6. Let adhesive begin curing
Leave the cobbles undisturbed atop the adhesive beads for the required curing time before grouting (typically 12-24 hours). Weight down any loose stones with bricks.
7. Grout joints
Sweep polymeric joint sand into the gaps between stones. Mist with water to activate bonding agent. Allow grout to fully cure.
8. Avoid traffic
Leave the adhered edging undisturbed for the full recommended curing time before allowing foot traffic or vehicles (often 7-14 days).
Cutting Cobblestones
Some cutting and shaping of cobblestones is often needed to achieve clean pattern lines and proper fit:
- Use a diamond blade masonry saw or angle grinder to cut cobblestones precisely. Make multiple shallow passes when cutting to avoid cracking the stone.
- Round off sharp cut edges using a concrete rub stone or masonry bit to prevent injury.
- Nip small chips from stones using a mason’s hammer and chisel to create smaller filler pieces. Wear eye protection.
- Use a grinder or rubbing stone to shape edges of cobbles for smooth curves. Work slowly to prevent overheating the stone.
- Minimize required cutting by choosing cobblestones sized appropriately for your pattern. Arrange stones for best fit.
- Cut pavers on a bench or solid surface. Contain water runoff when wet cutting. Wear a P100 respirator to limit silica dust exposure.
Finishing Touches
Apply these final steps to complete your cobbled edging:
- Sweep away all dust, fragments, and excess sand or mortar from the cobblestone surface.
- Use a soft brush and mild soap solution to clean the stones once fully installed, if needed. Avoid acidic cleaners.
- For mortared edges, apply a recommended sealer to protect cobblestones from stains. Read directions to avoid discoloration. Adhered stones don’t need sealing.
- Backfill behind the edging with saved topsoil. Compact it in place along the length of the border.
- Plant landscaping vegetation or lay decorative mulch next to the cobbled edge as desired.
Your artfully crafted cobblestone edging is now complete! Maintain its beauty by promptly cleaning any oil drips, pulling weeds from joints as needed, and re-securing any stones that settle or shift out of place over time. With periodic care, your cobblestone border can gracefully frame your asphalt driveway for decades to come.
Frequently Asked Questions
Q: Can I install a cobblestone edge against existing asphalt?
A: Yes, you can add a cobble border next to established asphalt. Just excavate the necessary trench, taking care not to crack the pavement. The installation process is the same.
Q: What kind of base is needed if my soil is sandy?
A: Prepare an enhanced gravel base with more depth in loose sandy soils. Compact 8 inches of gravel topped by 2 inches of sand to prevent settling. Also use longer landscape edging stakes to anchor firmly.
Q: Should cobblestones touch each other when laid in a pattern?
A: No, maintain even 1/4 to 1/2 inch joints between cobblestones to allow room for mortar bonding and grout. Spacers cut from 1/2 inch PVC pipe create consistent gaps.
Q: Can I use dyed mortar for more color?
A: Yes, mortar dye can add vivid color, but choose subdued earth tones to avoid an artificial look. Rich umber, burnt sienna, and charcoal gray complement natural stone hues well. Limit dyed mortar use to 25% of the mortar weight.
Q: How soon can I drive over newly installed cobblestone edging?
A: Allow mortared edging to cure fully for 5-7 days before driving over it. Let adhered cobblestone cure for at least 2 weeks before allowing vehicle traffic or snowplows near the edge.
Q: What maintenance is needed for cobblestone borders?
A: Remove fallen leaves promptly to prevent staining. Weed control is important; pull weeds as they emerge from joints. Inspect for loose stones; re-adhere promptly. Reapply joint sand if erosion occurs. That’s about it for ongoing care.
Conclusion
Installing a cobblestone border along your asphalt driveway provides long-lasting curb appeal and clearly defines the pavement edge. With careful base preparation and installation, a cobblestone edge can gracefully frame the driveway for decades while resisting weather, traffic, and ground movement. Choose cobblestones with colors and shapes that complement your landscape design. Allow creativity in laying out eye-catching patterns. Adhere to proper techniques for mortaring or adhering the cobblestones, using polymeric joint sand for durability. Your new cobblestone edging will enhance your property’s aesthetic character beautifully.