How to Build a Bluestone Walkway
Ask This Old House landscaping contractor Roger Cook helps a homeowner remove a flagstone walkway and replace it with bluestone.
- Start the process by removing the existing walkway with an electric-powered jackhammer. Be sure to wear eye and ear protection.
- Determine the width of the walkway (in this instance, referencing the the width of the front stairs). Spray paint marks six inches wider than the finished walkway to allow working space.
- Excavate the area between the sprayed lines about 6 to 8 inches below grade.
- Before backfilling, place a PVC pipe horizontally across the walkway using your height as a reference. This pipe can serve as a future chase for electrical or irrigation lines without disturbing the walkway.
- Rake the surface smooth and then use a gas-powered plate compacter to compact the subsoil.
- Next, add a mix of stone dust and ¾-inch stone to a depth of 2-3” and run the plate compactor over that layer. Continually add the mix 2-3” at a time, compacting between layers, to ensure a solid base, until you are 3” from finished grade.
- Set a mason’s line of 3 inches to match the height of the walkway and place it at a 90-degree angle to the front steps. To ensure the line is perpendicular, use the 3-4-5 method. Measure three feet horizontally and four feet vertically; the diagonal measurement in between the two points should be five feet if the lines are truly perpendicular.
- To fill the uneven underside of the bluestone, use a 12:1 mix of stone dust and Portland cement and hammer the bluestone down on top of it, filling any voids. If the stone still rocks, you may need to add more mix and hammer again.
- Once the stones are set and the stone surface is completely dry, spread polymeric sand into the joints, then carefully sweep or blow it off the stone surface. Wet the sand in the joints to lock the bluestone into place and minimize weeds and insects.