Sizing up the Landscape for Your Pool

Sizing up the Landscape for Your Pool

Before you make any decisions about the location of your pool, take a close look at how it will fit within the overall makeup of your property. A plot plan allows you to do this with ease. You will also need to consider such issues as access to the site by the contractor, landscaping elements, such as trees, your view of and from the pool, the slope of the site, the character of the soil, and any drainage problems.

Make a Plot Plan

Work with a plan showing all the features of your property. Later on, you can use the plan to draw in decks and other structures, as well as landscaping and lighting. Several companies offer excellent, reasonably priced computer software for this purpose. Otherwise, you can make a scale drawing on graph paper with provision for overlay sheets of tracing paper. The tracing paper allows you to sketch various pool ideas without redrawing the base each time.

Surveyor's drawings usually locate your property and show streets, property corners, and distances between corners, plus the locations of any structures on the site when the lot was surveyed. Available through your county recorder or title company, these plans make an excellent starting point for your base map; simply transfer information from the plot plan to your graph paper.

TIP: Save hours of complicated measuring by obtaining copies of a surveyor's plot plan, architect's drawings or house plans, and contour maps that illustrate vital statistics of the lot and buildings.

• Architect's drawings usually show site plan, floor plan, elevations, and foundation details.
• Contour maps show the slope of the land with a series of lines, each separated from the next by a fixed difference in elevation-very helpful if you are building a pool on a hillside lot.
• Ask for contour maps in the city or county engineer's office or in the department of public works.

Your Plot Plan

Your plot plan for a pool or spa should show the following:

• Dimensions of your lot Location of your house on the lot, as well as any doors and windows and the rooms from which they open.
• Location of decks, patios, walks, fences, walls, and other structures.
• Directions North, South, East, West.
• Location of easements or any other rights-of-way contained in your deed.
• Utilities (water, gas, and sewers) and underground wires that could affect your spa or tub location. (Units should never be located beneath utility wires.)
• Sun and wind patterns
• Potential problems beyond the lot lines that might affect sun, view, or privacy. For example tall trees or a neighbor's second-story windows or setback requirements.
• Contours of your lot. If you don't have a contour map, mark high and low spots, direction of slopes and natural drainage patterns.
• Natural features, such as rock outcrops, soil types, or wet spots.

Access for the Contractor

The minimum width for access to the pool site is about 8 feet, though 10 feet is preferable. Sometimes, small equipment can enter through a space only 5 feet wide, but because excavation will take longer, the cost will be higher. If equipment cannot be brought in, the pool must be hand dug at a prohibitive cost. This technique is still often used in southern California to excavate hillside lots with existing homes and landscaping.

You may have to remove fences and gates. If heavy equipment will cross a sidewalk, patio, or lawn, take measures to prevent damage. Again, this will be your responsibility. Though you don't want to build your pool over a gas or water main or under a power line, your pool site should have ready access to necessary utilities. Some pool contracts require additional payment for unusually long runs to utility lines. Check that these costs have been included in the builder's bid.

Trees and Shrubs

Don't build a pool or spa too close to trees and large shrubs. Leaves, blossoms, and fruit droppings near and in the water will add to your cleaning chores. And a tall tree or shrub may provide unwanted shade.

For trees or shrubs that you want to keep, try to locate your pool so that the prevailing winds blow the debris away from the pool. In addition, plot the shadows thrown by the trees; then determine whether or not you would welcome that shade in and around your pool during the swimming season.

Assessing the View

Pleasing aesthetics, privacy, and safety are concerns when you choose a pool or spa location. When seen from inside your home, the new installation should be an attractive part of the landscape. On the other hand, the view from a neighbor's upstairs window may infringe on your privacy. And if there's a beautiful view from your property, try to position the pool so you will be able to take full advantage of the view from poolside.

If children will use your pool or spa, you need either a clear view of their activities from the house or, as in the case of small children, you will have to be at poolside when they're swimming. Mark the fields of view on an overlay of your plot plan. If you've already decided on a potential site, use an enlarged plan of the proposed pool area to mark the fields; you will want a large plan when it comes time to mapping out your landscaping.

Slope, Soil and Drainage

Ideally, you want a pool site that's level and slightly higher than the land around it. The same applies for in-ground spas. The underlying soil should be stable and easy to dig. Also, you'll need a dry site, with good surface and subsurface drainage. Good drainage conditions will depend on the slope of the land and the nature of the soil.

By analyzing a contour map of your lot, you can determine where the land slopes and how steep the slopes are. You should also be able to locate any high spots, depressions, flat areas, or drainage paths. If you don't have a contour map, wander around your property and take note of any of these features; then mark them on your plot plan.

Even if your property has no ideal level area, remember that hillsides can become sites for magnificent swimming pools and spas.

Because soil conditions affect the ease of excavation and also have the potential for damaging or even destroying a concrete pool or spa shell, you must determine the type of soil underlying your property. Once you've zeroed in on a possible site, you can have the precise nature of your soil identified by having a core sample analyzed. Gravel, sand, silt, and clay require special design features in the pool or spa. Though the pool or spa contractor may have had experience with these conditions, you may want to consult a soils engineer.

Loam: Commonly called "garden soil," loam is ideal for a pool or spa site in many parts of the country since it's easy to dig. The walls of the excavation will be stable and not likely to collapse. In other areas, though, it may settle or compact causing damage to the shell.

Sandy soil: The bane of pool builders, sandy soil usually caves in during excavation. Because the walls must be shored up with wood or sprayed with concrete to prevent collapse, the construction cost is increased. Sometimes, a concrete pool in sandy soil must be built with a thicker shell, or closer spacing of steel reinforcing bars, or supported on pilings.

Wet soil: Whether waterlogged from surface runoff or in an area with a high water table, wet soil is best avoided, if at all possible. Excavating for a pool in wet soil is very expensive. And the pressure of the underground water can collapse an empty pool built in such soil, or float the pool out of the ground. This is also a risk with pools built near bodies of water where tidal variation can damage or even carry away an improperly anchored pool.

Expansive soil: Known also as clay, it becomes a problem only when a significant amount of water percolates into the ground. The pressure exerted on the sides of even a filled pool can cause it to collapse. Some communities ban pools that cannot be reinforced to withstand the pressure of wet expansive soil.

A concrete pool in expansive soil may have to be built with a thicker shell; it may also require expansion joints inside the pool between the shell and coping (the lip around the edge of the pool), the coping and deck, and within the deck. A trench dug around the pool and filled with loose material can help absorb the soil expansion. Surface drainage must be directed away from the pool area and any drainage lines must be made leakproof.

Corrosive soil: Despite the advent of plastic plumbing pipe, corrosive soil can still present a problem when constructing a swimming pool. Though metal pools and the metal wall panels used with some vinyl-lined pools are treated against corrosion, special precautions may be required in highly corrosive soil. Your pool contractor or soils engineer should be aware of any problems in your area.

Other considerations: Rock beneath the soil requires drilling and blasting and may add substantially to the cost of construction.

Filled ground is unsuitable as a pool site unless the soil was compacted properly (this is difficult to assess) or unless the bottom of the pool will be deeper than the disturbed soil. Even though you may not see evidence of fill, dig some test holes on your potential sites. If you find layers of different kinds of soil or any manmade debris, you can be sure that the area was filled.

Dealing with drainage: Usually, any natural drainage on the surface of your property or a neighbor's property can be diverted away from a pool or spa site. Surface drainage need not be a problem if you avoid building your pool or spa in a low-lying area from which water cannot drain. During storms, muddy water collecting there can spill over into the unit.

Water running off a slope or down a drainage path can fill your pool or spa with debris. If you can't find a site free from runoff, you can landscape the area to divert the water.

Sometimes, a soggy low spot or especially lush vegetation will alert you to an area of poor underground drainage on your property. Most of the time, though, the condition is hidden until you dig a test hole or start excavating your pool.

Ask your pool-owning neighbors if they had any subsurface drainage problems; you can also consult local soils engineers, pool contractors, and building inspectors.

Water drainage involves disposing of the pool or spa water if you have to drain it, and disposing of the water from the filter when it is serviced. Dumping 30,000 gallons of chlorinated pool water in your garden would kill all your plants-not to mention the damage it would inflict on neighbors' yards. For information on correct drainage and disposal of pool water, contact the state or regional office of the U.S. Environmental Protection Agency.

Whether you plan to install a spa or a pool, designing and building on a sloping site requires the services of experts. The steeper the hillside, the more important these experts are. The angle of the slope, the nature and stability of the soil, the design of the pool shell, and the method of anchoring the shell to the slope all must be considered.

Despite the problems, a hillside can allow a designer to create impressive designs. The pool can appear to soar into space or be nestled in a grove of trees. Few hillsides are too steep for a pool builder pools have even been suspended from the edges of cliffs.

Support and drainage: A hillside pool needs to withstand earth pressure on one side and have well-engineered support on the other. Downslope supports for the pool should be built on a solid foundation, preferably rock. Retaining walls on the upslope side, sometimes incorporating the pool structure itself, must be sufficient to contain a possible earth or loose-rock slide and resist earthquakes.

Surface water must be routed around the pool to a lower slope, and decks must be designed to prevent water from seeping into the ground near the pool.

Special considerations: Hillside sites also pose special construction problems for spas. For a portable spa, a level cut has to be made in the hillside and a retaining wall built to hold it up. Any retaining wall over a few feet high should be engineered by a professional. A slab made of reinforced concrete is then poured to support the spa.

An in-ground spa on a hillside also requires a retaining wall, but one on the downhill side. The wall supports the spa shell and helps to contain the sand base on which the shell rests.

Pool or spa access and adequate decking can be a challenge. It's a good idea to plan the area completely on paper, including all steps, decking, and structures. If the site is too confined, any installation may be impractical.

Finally, consider the costs involved. The additional expense of building a pool or spa on a steep hillside can occasionally equal and even exceed the cost of the unit itself. But if your lot is not excessively steep, expect only a moderate increase in cost.

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