What you need to know to shape, style, and install the floor of an outdoor sitting room
by GORDON HAY WARD
No matter what the size or style of your garden, sitting areas are central to its success. They are the destinations for paths and places to relax and entertain once you reach them. A sitting area can be as simple as two chairs under a tree off the back of your house, or as complex as a cooking and dining area deep in the garden.
CHOOSING THE SHAPE AND SURFACE
There is no such thing as a perfect location, but I always look for spots with some shade, interesting views, and the chance of a breeze on hot summer afternoons. After you have chosen a site for your sitting area, the first job is to decide on its shape and size. Use bamboo stakes or a garden hose to rough out the shape; when the design is set use stakes with twine to outline the edges. No matter what the shape, make the space larger than you first think it needs to be; you won’t regret it. The next task is to choose a surface material. Because a good garden echoes its surroundings, choose stone or brick that relates to your house and region: bluestone or mica schist in the Northeast; limestone in the Midwest; sandstone in the West. Brick fits in just about anywhere.
Each of these materials has its own shape and character, and therefore lends itself best to certain designs. Large pieces of geometric cut stone are best used to make a square or rectangular sitting area. Brick, also being rectangular but much smaller in size, is more versatile, so you can use it to form either geometric or free-form sitting areas. Randomly shaped fieldstones suggest irregularly-shaped sitting areas.
PREPARING THE BASE
The key to the usefulness and longevity of a sitting area is good drainage. Otherwise the year’s freeze and thaw, wet and dry cycles will cause heaving and sinking of your stones or bricks. Get a shovel and dig down at least a foot to see whether the soil under your new sitting area is gravelly and therefore free-draining, or clayey and therefore slow-draining.
If the soil is free-draining, excavate down six inches. Backfill the excavated area with three inches of finely crushed gravel (smaller than a quarter inch in diameter) or stone dust and tamp it with a hand tamper. Then add one to two inches of sand, depending on the thickness of your material, keeping in mind that the finished surface of the sitting area should be about a half inch above the adjacent grade in order to provide drainage.
If the soil in your intended sitting area is slow-draining, excavate the area eight to twelve inches deep. Backfill with five to six inches of crushed stone (three-quarters to one-and-a-half inch in diameter) and then put a layer of woven black plastic cloth on top of the crushed rock. The cloth will keep finer stone from clogging the spaces between the larger stones and inhibiting drainage. Cover the cloth with finely crushed gravel or crusher dust to a depth that will allow your paving stones or bricks to sit just above the surrounding grade. (If your budget is tight or you simply can’t decide on a type of stone, this gravel base itself, top dressed with one to two inches of pea stone, can be used for the sitting area. At some later point you can always remove the peastone and cover the gravel with stone or brick.)
Once you have spread the crushed gravel, tamp it well, and then level it with an eight-foot-long straight-edged two-by-four. This board will show you low spots to fill in and high spots to shave down. When the crushed gravel base is leveled, top dress it with two to three inches of sand so that when the stone or brick is laid atop it, x its surface will be about a half inch above the adjacent grade.
Although this final layer should be uniform, it should not be perfectly level. Your sitting area should slope ever so gradually away from your house–for every foot of length, your sitting area should slope an eighth to a quarter of an inch. You need to build this slight slope into your layer of sand. Use that same straight two-by-four board and a spirit level atop it to check the slope. Tamp down the sand, and you are ready to lay the surface material.
LAYING CUT STONE AND BRICK
Because each of these materials is flat on all sides and will fit tightly together, you can create patterns with them. It pays to spend some time with a scaled drawing of your sitting area to determine the best pattern; that drawing will help you determine the size and number of stones or brick you’ll need to order from a supplier.
Start the actual construction by laying one of the larger cut stones, or a pattern of brick, at the most important edge (by the back door of the house or at the entrance to the sitting area) and then lay three or four others in relation to it to get a sense of how it all will look. Once you’re happy with the layout, set each stone or brick onto the prepared base and then lift each one to be certain the sand underneath shows evidence that it is supporting the stone you set on it. If you find air pockets, sift a little sand into the cavity. Until they are properly supported, do not step on cut stones. Unlike brick, they snap easily if not uniformly supported.
If you are laying an irregular fieldstone sitting area, place six or eight stones on your sand base and see how the concave edge of one tucks into the convex curve of another. (If you need to shape fieldstone for a tighter fit, use a three-pound sledgehammer and a three-inch-wide mason’s chisel. Always wear eye protection and gloves.) Once you are happy with their arrangement, twist them down into the sand so they are settled snugly and about a half inch or three-quarters of an inch above the surrounding grade.
If you simply lay fieldstones without shaping them at all, you will end up with a number of gaps here and there between the stones. These are ideal places for planting low-growing plants, which will add to the character and color of your sitting area. Backfill those gaps with a mix of one part sand and one part topsoil and then plant these pockets with creeping thyme and other ground-hugging perennials.
Once you have the stones in place, tap them with a rubber mallet to set them firmly into your base material. Use a spirit level frequently to check that all the stones are level in relation to one another. A four-foot level will allow you to check the level across several stones.
To sit in one of these welcoming areas is a special pleasure, day or evening. My wife, Mary, and I gather with friends in our garden for a glass of iced tea or a meal, and when we do, it feels so right, so pleasant, and so rewarding to be able to sit in our garden, surrounded by the plants and natural materials and man-made objects that all go into making up a garden. H