DECORATIVE PAVING : The Down-and-Dirty Facts About Laying a New Patio

You can build an attractive and durable patio by laying bricks on a bed of fine sand without mortar.

Patios are commonly made of “paving bricks,” which are harder and more durable than ordinary bricks. Select “pavers” rated “SW” (severe weathering grade).

When buying bricks, check to be sure that all are of uniform size, straight and hard. Poorly burned bricks are subject to crumbling. Two bricks when struck together should produce a ringing sound, an indicator of good quality.

Bricks are priced by the thousand, but are often less expensive if purchased in prepackaged lots called “strips,” which contain about 100 standard bricks, or “cubes” of about 500 standard bricks. For mortar-less installation, choose pavers that are four-inches wide, eight-inches long, and 1 5/8- to 2 1/4-inches thick. You’ll need about 475 bricks to pave 100 square feet--an area 10-feet-by-10-feet, for example.

Before your brick order arrives, prepare a storage platform near the street or driveway and as close as possible to the job site. Lay planks on a hard surface and cover them with plastic sheeting. Stack the bricks so that most of them are on edge and the outer walls lean in slightly.

To avoid cutting bricks, pick a design that doesn’t require half-bricks at the edges. A good choice is a basket weave pattern, which has alternate pairs of bricks going in opposite directions.

Because unmortared pavers tend to shift, a firm restraint is needed at the perimeter of the patio or walkway. Brick-in-earth borders are easiest to install.

You can set a row of “sailors” (bricks standing on end, side by side) in a narrow trench. Or you can create a sawtooth edging with tilted sailors, which are set in earth at a 45-degree angle. Pressure-treated, wood-landscaping ties make a neat border. These should be anchored in place by drilling holes near the ends and center of each tie and driving in three-foot metal rods (“rebars”) about three-eighths of an inch in diameter.

Outline the area with a row or two of bricks. Then mark it off with stakes and strings. Lay out at least part of the patio in a dry run to work out any problems with your chosen pattern. For proper drainage, plan on sloping the patio away from the house about one-quarter inch per foot. If the patio does not adjoin a building, make the highest point in the center.

Remove the bricks. Dig out the paving bed to a depth of about four inches (brick depth plus two inches of sand.) If the area has clay soil or receives frequent heavy rains or snowfall, dig out another four inches and fill it with washed gravel. Dig a trench for borders along two adjacent edges. Allow for two inches of sand beneath brick borders.

Make a tamper by nailing a foot-square of plywood to the end of a 4-by-4 board. Tamp the excavated ground well.

Spread the sand. Level it with a board on edge. Moisten the sand and compact it with the tamper. Add new sand; spray and level again.

To keep out weeds, cover the sand with 15-pound roofing felt or polyethylene sheeting. With a knife blade, cut a few holes in the covering for drainage.

Set the two adjacent borders in place; make sure that they are at patio surface level. Then, beginning at the corner they form, lay the bricks in your chosen pattern.

Place the bricks firmly on the felt or plastic, pressing them tightly against one another. Use a 2-by-4 board or run a string across the patio to keep the joints aligned. Level the bricks by tapping them lightly with a rubber mallet. Be careful not to shift the bricks. Put in the other two borders last.

Pour sand on the bricks and sweep with a broom to fill the joints. Dampen with a fine spray. Wait 15 minutes and repeat until the joints are filled. It’s a good idea to repeat the sanding at two-day intervals until the joints are filled and the bricks are stabilized.

For more permanence, substitute a bed of hard-tamped limestone dust for sand. Put one-half-inch of sand on top of the weed barrier for leveling the bricks. Then fill the joints with a dry mixture of one part portland cement and five parts sand. To avoid staining the bricks, apply the mixture when the bricks are dry and brush off all traces before wetting.