Fountains and Swimming Pools

Swimming Pools
Swimming pools are like substantial fortunes, practically everyone would like one and few obtain them. In the case of the swimming pool, the problem is practically always one of cost. Compared to other things which homeowners can build or have built to enhance the recreation facilities of their properties, swimming pools are extraordinarily expensive. A few lucky persons have succeeded in building pools of fair, if not generous, size for $3000 or less, but not many homeowners are, or can hope to be, so fortunate. Prices of family-sized pools vary greatly. The variations are related not only to the region in which the pools are built but also to what is included with the pool. A simple pool which must be filled with the garden hose and which is drained into a near-by ditch or creek may cost one sum; whereas another pool built in the same community but equipped with accessories such as a bath house, provision for filtering, sterilizing and re-circulating the water, and with a more elaborate drainage system can cost several times as much. There is no such thing as a standard price. As this book is being written, two contracting firms are offering to build pools in the northeastern states at guaranteed prices. One is offering a 20 ft. by 40 ft. concrete pool with diving board, ladder, drains, gutters, etc., for $8300. The other is offering a 16 ft. by 30 ft. pool without accessories for $4775. Even the higher-priced of these two pools would be considered too small by many swimmers, and, of course, neither price includes much extra equipment. Some of the accessories which have been installed in conjunction with private swimming pools are strictly in the nature of luxuries. They include such equipment as heating systems for the water, elaborate lighting systems, elaborate buildings which contain not only lockers and dressing rooms but also bars, recreation rooms, kitchens, etc. On the other hand, some accessories are essential equipment. For example, some of the prices quoted by contractors cover the excavation work and the bare pool, but a water supply of some sort and a drain must both be constructed before the pool can be used. Few owners of pools wish to get along without a diving board, yet the minimum prices advertised often do not include this piece of equipment. In a considerable number of communities water from the municipal system costs so much that a pool which is emptied, cleaned, and refilled half a dozen times in a season can use up two or three hundred dollars' worth of water. In some regions where water supplies run short in the middle of the summer filling the pool might be forbidden. In such localities, the water must be filtered, sterilized, and re-circulated. Another accessory which may be required by law is a filter through which the drain water is passed before it is discharged into a stream or other drainage system. Accessories such as these can add considerable amounts to the cost of a swimming pool.

When building costs decline, the cost of constructing pools also goes down. Furthermore, with more and more homeowners installing private pools, contractors will work out simpler methods for their construction. Even when all of these factors are taken into account, however, it is not highly probably that the average price of private swimming pools will, in the near future, come as low as the average price of a good car. Nor is there much chance that prices of pools will become standardized as car prices are standardized. The cost of building a pool on your particular site will continue to be largely a matter of negotiation between you and your contractor; and such factors as soil conditions on the site, the dimensions of the pool, the accessories you desire, and the contractor's past experiences with pool construction will influence the final cost in such ways that you may pay a good deal more or a good deal less for your pool than some neighbor paid for his.

A major proportion of private swimming pools are constructed of poured concrete. Some pools have been made of plain concrete, that is, concrete without steel reinforcement embedded in it, but the massive walls which are required in this method of construction consume prohibitive quantities of cement and aggregrates. Concrete is an excellent material for pools. If due attention is paid to proportioning the ingredients, including the water, mixing and placing them and to thorough damp-curing, a high-strength concrete which will last practically indefinitely can be produced. A smooth finish which greatly facilitates cleaning of the pool can be given to the inner walls by using dressed lumber or, better still, plywood to face the forms in which the concrete is poured. Expansion joints, gutters, and drains are easily made by proper shaping of the forms. The natural color of ordinary concrete is not unpleasant in a pool, but if desired, the pool walls can readily be finished with whitewash which imparts a pleasant blue color to the water. Next to concrete, the chief material for swimming pools is steel. However, the number of concrete pools built greatly exceeds the number of steel pools. Steel pools are made of fairly heavy steel plates which are shaped at the factory or at a steel fabricating works before they are shipped to the site. The pool is put together by assembling the plates in the excavation which has been made for the pool. Some steel pools are formed with riveted joints but most of them are now made with welded joints. Even in thickly populated regions steel pools are usually offered by only a few contractors, and the ones built are constructed only by these firms. General contractors will not undertake them and they are quite beyond the capabilities of amateur builders. A steel pool is never cracked by frost heaving, although it is theoretically possible for the bottom of such a pool to be severely bulged if water should accumulate under it and then freeze. The weakness of steel pools is their susceptibility to rust, especially at the water line where air and water meet. Steel pools are usually painted with asphalt paint to retard rusting. It is important to see that this coat of paint is well maintained at the water line and also at joints.

Successful pools have been made by a variety of other methods and with numerous other materials. The most important variation to date is in the method of placing the concrete. Instead of pouring it in forms, some builders line the excavation with a suitable network of reinforcing steel, then apply the concrete with a pneumatic gun. The concrete mix must be specially proportioned for the process, and, of course, special equipment is required for its application.

This form of concrete and also the method is often referred to as Gunite. Strong, watertight pools can be made by this process when it is carried out by skilled workmen. Nevertheless, it is nowhere near so widely used as the traditional method of pouring the concrete in forms. Since much of the cost of building a swimming pool is due to the fact that the walls must be strong enough to resist the pressure of the earth upon them when the pool is empty, many attempts to lower the cost have been made by changing the traditional pool shape. All engineers know that if the walls of a buried structure such as a pool have the shape of a hemisphere, they can be made much lighter because a thrust at any point on the outer surface tends to be resisted by a considerable part of the structure. Accordingly some pools have been built in this shape or in shapes that lie between it and the conventional box shape.

Also pools have been lined with other materials such as brick, stone, and composites bound with asphalt. The catch in attempting to lower the cost of pool construction by using other materials is that few building materials which are adequate at all cost as little as concrete. When a pool is made of brick or stone laid up in mortar, it is always necessary to apply waterproofing material to the inside of the walls. Steel reinforcing may be required unless the walls are extraordinarily massive. A great many experiments have been made along these lines, and a few builders have successfully built a fair number of pools in their communities at prices somewhat lower than the pools would cost if built by traditional methods. Nevertheless, in spite of all the experiments no method has yet seriously challenged the standard one of building pools in the shape of an oblong box with straight sides, nor does any material yet threaten the supremacy of poured concrete. Private outdoor swimming pools range in size from those which are too small for pleasurable swimming to pools of the same dimensions as are built for swimming contests. Swimming pools on home sites have been built in the following lengths and widths (and probably also in others), the measurements being given in feet:

• 16 x 30 20 x 60
• 18 x 36 25 x 60
• 16 x 40 30 x 75
• 20 x 40 32 x 64

Depths vary also. Most pools are graduated in depth. The depth of the water at the deepest part, directly over the drain, is usually 8 ft., 6 in. or 9 ft. The depth at the deeper end ranges from 6 ft., 6 in. to 7 ft., 6 in., and the depth at the shallow end is usually 3 ft., 6 in. or 4 ft, the diving board should be placed so that the diver will escend into deep water. Three feet, 6 in. is a little too deep for small children, especially children who are just learning to swim. Some families with small children prefer to build a separate swimming pool for them. The depth of the water in children's pools should run from about 24 to 36 in. Wading pools for children should not be more than 15 in. deep.

There are three general systems for handling the water requirements of small swimming pools. The most common one, called "fill and draw," is the system of filling the pool, using it for an interval of time, ther draining it and refilling. Some owners vary the scheme by not draining completely but drawing the water down so that a thousand or so gallons can be added. Disadvantages of this scheme are that the water grows progressively dirty, draining and refilling are likely to be neglected, and a schedule of draining and refilling which is based primarily on time does not take into account the possibility of severe contamination of the water in the pool occurring at the start of the cycle. In spite of its faults, this is the system which is used for most small private pools. The initial installation costs very little for most pools supplied this way are simply filled with a hose. Everything considered, it is the best system when water is available at low rates and when restrictions are not clamped on the use of water during the swimming season.

The second scheme is called "flow through" because water enters constantly and drains away constantly. The pool is emptied only when it is necessary to scrub down the sides and bottom, usually not more than twice a season. For small pools the rate of flow need not be great, and often is as low as 3 gallons a minute. Springs, flowing artesian wells, and brooks are good sources of supply for flow through pools. The plumbing required is simple and adds little to the cost of the pool.

The third system is similar to what is required by law for public swimming pools in many localities. This is a re-circulating system with provisions for filtering and disinfecting. Pools which get only average use need be filled only once a season. The original water is used over and over again and water is added only to make up the loss due to evaporation. An adequate re-circulating system can cost $1000 or more, and there are other disadvantages. The chlorine used for disinfection of the water is irritating to eyes and nose. In climates where summer temperatures are hot for considerable periods, the water in the pool may become uncomfortably warm. The system requires a pump and motor, and, therefore, the purchase of a moderate amount of power.

Water inlets are required with both the flow-through and recirculating systems. The best location is at the shallow end of thepool about 1 ft. below the water line. Two inlets rather than one are recommended in order to obtain good distribution of the fresh water. Large pools are sometimes equipped with more elaborate sys- tems of inlets which are designed so as to distribute the fresh water immediately throughout the pool, but this is not an important consideration in small private pools.

The average homeowner has little opportunity for choice among these systems. If his property is located where a dependable supply or pure flowing water can be tapped, the flow-through system will be adopted naturally. Lacking a flowing water supply, the next best bet is a fill-and-draw system. However, if the price of water or other considerations make this scheme unfeasible, equipment for filtering, disinfecting, and re-circulating must be included in the plans for the pool.

Drainage systems
Disposing of the drainage water from a swimming pool is a simple matter in the majority of localities, but it can be complex in some. In some locations the pool can be drained into a public sewer system. Rather often local authorities will require its drainage into a storm sewer rather than a sanitary sewer, but this imposes no hardship on the property owner. Drainage to a sewer often involves the purchase of a pump and motor in order to raise the pool water to the level of the sewer. In rural communities, especially, the pool can be drained into a stream. However, such drainage is not universally permitted. States with strict sanitary laws sometimes require that the drainage from a swimming pool be filtered or otherwise purified before it is discharged into a stream. A filtering or disinfecting system for the drain water will add a not inconsiderable amount to the cost of the pool, but where it is required, there is no avoiding it.

Diving boards
No pool is complete without a diving board. A good many home pools are equipped with diving boards which are far from satisfactory, either because they are not properly dimensioned or properly mounted.

A simpler type of diving board
This is a more amply dimensioned board than is customarily built for residential pools. Its mounting must be planned when the pool is built and provisions made for the footings which are fixed in the masonry. The mountings are of poured concrete, and they are embedded in the soil outside the walls of the pool. The concrete anchors are, of course, concealed by the terrace paving or other ground cover. The board itself is preferably a commercially manufactured diving board made of some such material as laminated Douglas fir. Such boards are available in lengths ranging from 8 ft. to 16 ft. The diving board can be, on the other hand, a altogether a home-made product and is more adapted to swimming holes than to masonry pools. Of course, it is possible to make a mounting such as is shown in this figure and to use on it a factorymade diving board, but this is not ordinarily done. Instead, local sawmills or lumber yards are searched for a wide plank, 2 or 3 in. in thickness, which is springy, free of knots, and strong. If the plank selected turns out to be too stiff, it can usually be made limber enough by tapering it somewhat. The tapering is a tedious process. Usually the board is first shaped roughly with an adze and is finally smoothed with a draw shave and plane.

Gutters and drains
Public and other large pools are regularly equipped with scum gutters on all four sides. These gutters carry off floating dirt and debris. They are sometimes omitted altogether in private pools, and pool designers generally agree that in such pools they need be included, if at all, on only the two long sides. If they are included, it is very important to have them level throughout their lengths. In fact, they are often ground down to level after the concrete has hardened. The gratings which cover the openings in the gutters and also in the drain

Illumination
Many private swimming pools are not lighted at all. When used at night, starlight or moonlight proves quite adequate. On the other hand, some homeowners do desire more brilliant lighting. There are two systems of artificial illumination. In one the pool is lighted by means of fixtures actually under the water and arranged so as to make the water luminous. Some light is cast on the diving board and surrounding pavement by the luminous water, but, generally speaking, the surroundings of the pool are in darkness. In the other system, outdoor floodlights are supported around the pool in such positions that they illuminate the pool environs and the surface of the water. Because this arrangement does not light up the water, the two systems are often combined. Underwater illumination is best when it is planned before the pool is built. Niches must be cast in the pool sides for the recessed, waterproof fixtures, and conduits must be included for the wires. Switches for turning the lights on and off should be located conveniently. One good arrangement is to provide them at two points, one near the pool and another at the house. The location near the pool makes it possible to turn the lights on without going to the house when darkness comes on during a swimming party. The second location enables the host to turn off the lights after all his guests have left the pool. Illumination for a particular swimming pool should be designed by someone who has had considerable experience with it. An adequate system costs a fair amount of money, but it will not be efficient if it is inexpertly designed or installed. A simple outdoor spotlight fastened to the house or a tall post and placed so that it will not shine in the eyes of persons using the diving board is adequate lighting for small pools built on a limited budget. An important point in relation to the overhead illumination of swimming pools is to place the lights back of the pool and the curbing or pavement which surrounds it so that the swarms of bugs which are attracted will not find their way into the pool.

Other accessories
Of the variety of luxurious accessories that can be built in conjunction with a swimming pool, a bathhouse s probably the one most often needed. If bathers must go to the house to change out of their wet suits, some damage to rugs and floors is almost inevitable. The house is a particularly inconvenient place for clothes-changing when a large number of guests are being entertained.

A simple bathhouse
Structures of this kind are not inexpensive even when they are small because of the plumbing that is required. As we have already mentioned, people with plenty of money sometimes go much farther in the provision of facilities for clothes-changing, eating, recreation, etc., at the pool. A very good arrangement, if there is money available for it, is a building which combines dressing rooms, showers, and some form of indoor recreation such as a pool table to which a retreat can be made when a shower comes up during an outdoor party. Facilities for serving drinks are practically essential in a setup as elaborate as this. On estates outdoor recreation centers combining tennis courts, swimming pool, and a building of this kind are not uncommon. Elaborate buildings can include also kitchens, dining rooms, bars, and facilities for listening to music or looking at television. The design of swimming pools is properly a matter for engineers or contractors who have had a wide experience with them. There is no such thing as one design which is adequate for all locations or even a majority of them. The nature of the soil and the height of the water table must both be considered in determining how the pool should be based so as to avoid uneven settling and consequent cracking. Likewise, the nature of the soil which will press upon the sides of the pool is a considerable factor in determining how much strength must be built into its walls. For example, solid rock will exert little or no pressure on the sides of the pool even when the pool is empty, but wet clay will exert a great deal. The sides of rectangular pools are often designed on the same principle as retaining walls, but, more often, they are designed as panels and are given a considerable degree of tensile strength by incorporating a large amount of reinforcing steel into the concrete. Even the proportion of this steel and the best ways of placing the concrete around it are engineering matters which cannot be generalized. Although it is true that some homeowners, without previous experience in masonry, have designed and built fairly successful pools, the procedure is risky and is not recommended. Sometimes some money can be saved by having the excavation done separately from the actual construction. If the excavation is made, the builder will not have to allow for such expensive contingencies as the striking of bedrock or a strong flow of ground water. However, the engineer who is to design the pool should be engaged before the excavation is made; or if it is to be built by a contractor who does his own engineering, the contractor should be\ approached first even though no contract is to be signed with him until after the hole is dug. These preliminary contacts can save you money because an expert will have a fair idea of the condition that probably will be encountered underground and can perhaps suggest changes that will reduce the cost. An example of this occurred on a site where expert observation of surface features indicated that the bedrock under the soil sloped steeply in one direction. An expert suggested changing the pool layout to take advantage of this slope and save costly excavation of rock.