How To Build An Interlocking Block Garden Border Fence

An artfully arranged band of bricks handsomely defines the boundary between grass and garden. And if you install the bricks flush with the ground, they also serve as a handy mowing guide: You can run the wheels of a push mower right on top of the border edging and pretty much dispense with the string trimmer.

Some people set the pavers in concrete, but there's no need if you make a proper dry bed. That means digging down past the loamy topsoil to prevent frost heave from disrupting the bricks come winter; once you do, laying a bed of compacted paver base and stone dust gives the bricks a solid foundation and provides drainage while preventing weeds or roots from coming up.

Follow along as This Old House senior technical editor Mark Powers guides you through the installation of this functional yard accent.

Overview of Brick Garden Edging

SATURDAY: Form the trench (Steps 1–7).
SUNDAY: Set the bricks (Steps 8–12).

Steps for Landscaping Bricks for Edging

1. Order the Bricks

Man Lays Length Of Rope Along Edge Of Garden Bed

Lay a length of rope along the edge of your garden bed, following its contours.
Mark the rope at the end of the bed with tape, pull it taut, and measure the rope up to the mark. Divide that length in inches by the width of the bricks to calculate the number you'll need, then add 10 percent to your order. For example: 324 inches ÷ 4 inches (brick width) = 81 bricks + 10 percent = 89 bricks.
Make sure to buy clay pavers, sometimes called severe-weather-rated bricks.

2. Scout the Curves

Man Edges Bed With Bricks Against Grass Line

Line the edge of the bed with bricks, tight against the grass line—close to one another but not quite touching, leaving a gap for the sand.
To work around soft curves, fan them out slightly; for tight curves, find the center or peak of the curve and leave a triangular gap, as shown. The widest point of the gap should be no wider than a brick.

3. Mark the Bricks

Man Marks Bricks To Fill Gaps In Curves For Brick Garden Edging

You'll make angled keystone bricks to fill the triangular gaps in the curves. Center a brick over a gap, and use the masonry pencil to mark its end where it overlaps its neighboring bricks, as shown. Mark the opposite end of the brick in the same way.

4. Transfer the Marks

Man Transfers Marked Bricks To Form Cutlines

Flip the brick over, and transfer the marks from each end onto its face. Use the masonry pencil, and a straightedge if necessary, to draw lines connecting the marks at each end of the brick to form your cutlines.

5. Cut the Keystones

Man Uses Circular Saw To Cut Through Marked Bricks For Brick Garden Edging

With the brick marked, rest it on a work surface with the cutlines faceup. Fit the circular saw with the segmented diamond blade. Adjust the depth of the blade so that it will just barely cut through the brick in a single pass.
To minimize dust, trickle water onto the brick as you cut; use the nail to puncture the bottom of the water bottle to create a steady trickle. Set the cut keystone brick into the opening to make sure it fits.

6. Dig the Trench

Place the tarp over your grass to collect soil as you dig.
Using the spade, dig a trench with straight sides along the length of the bed, working from the grass line into the bed. Make the trench several inches wider than the length of your bricks.

7. Check the Depth

Man Checks Depth Of Dirt Trench With Measuring Tape For Brick Garden Edging

Dig until the soil changes color, indicating that you've gotten past the topsoil.
Measure the depth of your trench, as shown; it should be at least 6 inches deep to allow for a 2- to 3-inch layer of paver base, 1 inch of stone dust, and the bricks set flush with the ground.

8. Pack the Paver Base

Spread the paver base evenly throughout the trench, stopping periodically to pack it down with the tamper, as shown.
Continue to add the material in small batches until it forms a base that's at least 2 to 3 inches deep.
If you had to dig deeper than 6 inches to reach past the topsoil, continue to add and pack the paver base until the depth of the tamped trench is equal to the thickness of a brick, plus 1 inch for the stone dust.

9. Mix the Stone Dust

Man Mixes Stone Dust And Portland Cement

In a large wheelbarrow, mix together stone dust and portland cement in a 6:1 ratio, using six shovelfuls of stone dust for every shovelful of cement.
Use the garden hose to mist (but don't soak) the mixture to activate the cement and make it easier to mix and shovel into the trench.

10. Lay the Bricks

Working in stretches several feet long, use the trowel to cover the paver base with the stone-dust mixture.
Press the bricks into place one at a time, tapping them down with the rubber mallet.
Make the face of each brick flush with the ground on either side of the trench and with the brick preceding it. Continue, brick by brick, and set the cut keystones at curves, maintaining a consistent gap.
Use any leftover stone dust to backfill along the back edge of the bricks, then cover it with soil.

11. Fill the Gaps

With the bricks set, pour polymeric sand over them and use the brush to sweep it into the spaces between them, as shown.
Working your way down the bed, whack the bricks with the rubber mallet to force the sand to pack itself tight.
Continue to fill the gaps until the sand is flush with the faces of the bricks and won't settle any farther.

12. Hose off the Edging

Brush away any excess polymeric sand or dust; either one can stain the bricks if it gets damp.
With the hose, wash the edging with a gentle spray, dampening the sand between the bricks without dislodging it. As the sand absorbs water, it will set, acting like grout to lock the bricks in place for years to come.

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