Choosing and Assessing Your Site
The contour is the most significant feature of your landscape. No site is perfectly level. Many are generally flat, however, and that will help keep construction -- especially of a patio -- uncomplicated. A slope might require grading the site or building a retaining wall to accommodate a patio.
Hillsides offer many design opportunities. Land sloping away from a high spot can create magnificent views, for instance. Land that slopes uphill from a patio site provides natural privacy and shelter from the wind.
If you have to level the ground to create a patio site at the bottom of a slope, you can remove soil to form a flat spot, fill in a low spot, or use a combination of both methods.
Grading and filling often creates a surface of unstable soil that settles unevenly. This can stress and crack a patio surface. Tamp and firm the loose surface thoroughly before building the patio.
If the slope's remaining soil is unstable, build a retaining wall to keep it from washing onto the patio. A retaining wall also increases the sense of enclosure produced on a patio nestled into a hillside.
Soil composition and compaction, characteristics that affect your site and how you prepare it, vary widely.
Loose, sandy loam absorbs water and drains quickly but erodes easily. In sandy loam and silted soil, local codes may require concrete footings under the perimeter of your patio.
Clay is dense and sheds water, which can create runoff problems. In this case, you may need to install swales or drainage lines that empty into a dry well or catch basin. Many local codes prohibit direct drainage of groundwater into the storm sewer system, and all codes prohibit routing drainage onto another person's property.Sun, shade, wind, and rain
To help ensure a pleasant and inviting patio instead of one that goes unused, pay attention to weather patterns. If the sun shines on the patio location throughout the day, for instance, it might not be a comfortable place to relax in the afternoon. Harsh winds will limit the use of the patio, but a wall with an open surface could transform them into pleasant breezes. Study the way the weather affects your site, and plan accordingly.
Solar heat and light on a patio varies throughout the day -- and seasonally. The earth's movement causes sunshine and shade to shift during the day. Working with nature is always more efficient than working against it, so place your patio where sun and shade patterns correspond to the times you want to use it.
Observe the sun's daily movement across your property during the warm months. Drive stakes into the ground to track the changing shade patterns. Make notes and sketches to use when you put your plans on paper.
Notice the wind patterns in your yard. If possible put your patio in a spot that's sheltered from strong prevailing winds. Build a slatted fence or plant a windbreak to buffer strong winds. For rain protection, install a solid roof over a part of your patio.Microclimates
If you've ever noticed a difference in temperature when you move from a patio into a yard, you've experienced the effects of a microclimate. Microclimates are small areas within a site where the weather patterns are different from the general area. Microclimates are the result of many factors, including terrain, landscaping, and the location and design of structures.
Different materials used in structures absorb and reflect different amounts of heat and light from the sun. Plain concrete, for instance, reflects more heat and light than dark bricks. Such a surface might feel comfortably warm, but reflected light could make it seem harsh and glaring.
A dark material like brick or precast pavers won't reflect sunlight as harshly, but it will absorb heat, which can make the surface uncomfortably hot underfoot during the day. The stored heat, however, radiates during the cool evening and extends the use of your patio after sunset.
A hilltop patio feels warmer on a calm day than one at the bottom of an incline because cooler air is heavier and flows downhill. Retaining walls, fences, or house walls built around a patio that's in a low spot can trap cold air, making the patio quite cool in the evening.
Walls and fences frequently create microclimates. Where you put a wall or fence and how you build it affects the force of the wind. Solid walls usually don't reduce winds. That's because a low-pressure area forms on the side away from the wind, drawing the wind into the very area you want to protect. The wind swirls over the top and drops back down -- with equal force -- at a distance from the wall roughly equal to its height.
Walls with lattice panels on top or open patterns laced into the surface will reduce the force of the wind and usually provide enough screening for privacy.
If your proposed site is already shaded during the times you'll use the patio, decisions about location are easier to make. But if you don't have much flexibility in patio location, you can alter the environment.
Plant trees and other plants to shade a site that gets too much afternoon sun. A pergola over the patio can filter the sunshine, or install a roll-up awning, which you can retract when it's not needed.
Roses or vines climbing up an arbor will create a private shaded spot for outdoor reading, without blocking the breeze. Vines climbing a lattice wall cool a site that gets hot in the late afternoon. Or you could try a compromise: Build the patio in a location that has partial shade and partial sunlight during the hours of greatest use.What to do with the dirt?
Landscapers often level other parts of the work site with the soil removed during grading -- a technique called cut-and-fill. Cut-and-fill eliminates the expense of disposing of excess soil, as well as the cost of purchasing fill dirt.
Cut-and-fill works best, of course, when the amount of soil removed roughly equals the amount needed in fill areas. If you have excess soil from grading, you can use it to construct raised planting beds or to fill planter boxes in walls.
Because you'll probably remove more than just topsoil, not all of the excavated dirt will be suitable for planting beds. Instead make berms -- low mounds of earth -- with it. Don't spread excess soil around trees even temporarily. Just a few extra inches of dirt over tree roots can suffocate roots and kill the tree.Choosing your site for shade
A north-side patio, in almost constant shade, may be too cool for comfort. Locating a large section of the patio beyond the shadow of the house produces both shady and sunny areas. Consider a detached patio for comfort in a climate that's cool year-round.
A patio with a southern exposure receives sunlight most of the day, but from different angles as the seasons change. Summer sun is high; winter sunlight is low. A lattice-covered pergola could filter the summer sun but allow full sun in the winter.
Sunlight warms an east-side patio in the morning, but this side of the house becomes shaded sooner than others. That's great for morning coffee but can make evening hours unpleasantly cool in mild climates. Here, too, a detached patio provides a solution.
A west-side patio starts the day in the shade, but by early afternoon, becomes too hot to use. Here's where a wraparound patio can help, offering you a chance to follow (or avoid) the harsh sun. Use natural or man-made shade to create a comfortable site.Picture-perfect plans
Take your camera along and snap plenty of photographs when you assess your site. Photographs call attention to details you may have missed because you see them every day. For example, you may have forgotten that the neighbors can see right into your living room window. Photographs will remind you that you need to correct this in your patio plans. You may have gotten used to how unattractive your utility shed is. A photo will tell you that you need a lattice screen.
Photos are especially helpful when you begin putting your plans on paper. Your site analysis will be a record of the characteristics of the landscape that need attention. Use the camera to help keep track of the ideas you want to include on this drawing.Fix foundation drainage first
If water gets into your basement, don't build a patio until you've determined the cause and fixed the problem. The problem may simply be that the ground slopes toward the foundation of your home instead of away from it. If so, the following is an easy solution.
Slope the soil next to the foundation away from the house at least 4 feet. You may have to bring in new soil to make a slope of this width.
Faulty or inadequate gutters and downspouts may also be the culprits. Check the joints in the gutters and the outlets where the downspouts connect to them. Seal any joints that are letting water through. Often adding an extension to the downspout -- or even just a splash block -- cures the problem.