By Michael Swiderski, Ph. D.More in Blog Cabin
The cobblestone at Blog Cabin 2011 sits atop a concrete base. Using a hammer drill, drain holes were drilled through the concrete to allow water to pass through and drain out.
The cobblestones need a layer of stone dust to bed down the stones when pressure is applied. Spread 2” of stone dust on top of the concrete pad and inside the brick border. Level the dust before laying cobblestone.
Lay the sheets of cobblestone down on the prepared stone dust base. Dry-fit all the stones in place. The cobblestones will lay atop the stone dust but must be flush with the top of the brick border. Once a sheet of stone is laid down, it may be walked on gently. Continue laying the sheets of stone until the entire area is covered.
Stones must be trimmed to fit inside the brick border. Use a pencil to sketch the cut mark on the stone. Rent a portable concrete cut-off saw (about $50 per day) and cut the stones to fit, following the sketched line.
Safety Tip: Using a portable concrete cut-off saw is dangerous. Use caution and follow the directions provided by the rental center. Wear heavy boots, earplugs and safety glasses.
To set the stones into the base of stone dust, lightly hand-tamp the entire stone surface. The hand tamper will compress the stone into the dust, stabilizing the sheets. To protect the stones from the tamper, cover them with a heavy towel or drop cloth.
Once stones are set in place, sweep the cobblestone surface clean. Place duct tape over the brick border to protect the brick from the epoxy grout.
The grout recipe is easy to follow. Empty a bag of silica sand into the mixer. Pour in the two-part epoxy grout. Fill the double container with water and pour it into the mixture. Mix for three minutes. Hand-spray the stones, using a fine-mist sprayer. Do not soak.
Empty the mixed grout onto the stones and squeegee the sand and epoxy grout mixture around to cover all of the joints between the stones.
Builder's Tip: On a hot day, the stones will warm up and the water spray will evaporate. Keep spraying as needed prior to spreading the grout into the joints.
The sanded grout joints will set up by themselves. No pressure is needed to compress the sanded joints.
Use a push broom to sweep the excess grout from atop the stones. Sweep the stone-covered area clean (Insert Image Jack 8112). Pretty simple isn't it? Remove the duct tape (Insert Image Jack 8099). Allow the grout to set for 48 hours prior to placing heavy objects on the stones.
Backfill the outside of the brick border with dirt, mulch or sod. The backfill may be spread level with the top of the border bricks.