Adding a hot tub or spa to an outdoor living area is an improvement that will afford much pleasure. A hot tub is less expensive than a swimming pool, uses less water, and is easier to install and maintain.
Either is conducive to relaxing and socializing. A hot tub or spa fits into a small space, making it an ideal choice for an out-of-the-way place. Whether purchased as a self-contained unit or as separate components, the equipment includes a tub, pump, filter, heater, thermostat, piping, and insulated cover.
Optional features include water jets and built-in lighting. Even if you buy a complete unit, you will need to do more than just hooking it up.
A spa without a deck around it, steps leading up to it, and a privacy fence around it will look ungainly as an unframed above-ground swimming pool. The whole point of having a spa is to be able to luxuriate in the soothing water. Therefore, you must design and build an appropriate setting.
Choosing The Location
There are many factors to consider when you choose a location for your tub or spa. One is privacy. Take advantage of plants, fences, walls, or existing screens, or build a fence or an enclosed structure similar to a Japanese bath house.
Another factor is convenience. Make sure the tub is closed to a dressing area. Take advantage of attractive vistas, and consider using the tub or spa as a focal point in a garden or patio.
Install lighting in and around the tub so you can use it at night. Climate is also a major factor, consider sunlight, shade, wind, and snow. Generally, an outdoor spa should take advantage of late afternoon sunshine (unless you are in a hot climate) and be sheltered from prevailing breezes.
In cold climates, the installation should have valves for draining equipment and tub separately, so you can keep the equipment from freezing without having to drain the tub.
Also avoid placing a tub or spa beneath eaves where snow will slide into it. Any outdoor installation requires an adequate foundation for the tub and proper ventilation to reduce condensation.
Tub Or Spa: Which One?
Basically, hot tubs are wooden barrels and spas are shells manufactured of plastic materials. This distinction is complicated by the fact that some hot tubs have acrylic liners and some spas are free-standing units with wood skirting or are made from concrete.
However, tubs and spas have other basic differences — in maintenance, durability, appearance, and operation — all of which are fundamental considerations.
Beveled wood staves held in place by iron compression hoops form the sides of a hot tub. A dado groove near the bottom of the staves holds the wood floor in place. Most tubs are made of redwood — usually vertical grain, all-heart grades.
Some are made from less expensive grades that include sapwood, cedar, oak, or teak.
Depending on the species and grade of wood, a tub will last from 10 to 15 years. Make sure the wood is kiln-dried so that it swells evenly when the tub is filled with water. The constant swelling of the staves renders the tub watertight.
A tub can be any size or shape, but round tubs 5 or 6 feet in diameter and 2½, 4, or 5 feet tall are most common. Some tubs are less than 4 feet in diameter and others are as wide as 12 feet.
A standard 5-by4-foot tub holds 500 gallons of water and weighs 5,000 pounds when full of water and bathers.
Install a hot tub at ground level or on a reinforced deck. A tub requires a substantial foundation — either a steel-reinforced concrete slab at grade level or a system of footings and piers for elevated tubs. The floor, not the sides, carries the weight of the tub.
Tubs have a rustic and natural appearance; they blend well with decks, gardens, greenhouses, or patios. Hot tubs are harder to clean and maintain than spas because of the texture of the wood and the angles and corners inherent in their design.
On the other hand, tubs are easier to transport and relocate and generally cost less. Early spas were made of fiberglass and covered with gelcoat. More modern materials include formed acrylic reinforced with fiberglass and formed Centrex® thermoplastic, which needs no reinforcement.
The outside of the spa varies. Some are designed to be installed in the ground or in a specially designed box that is filled with sand. Others are free-standing with wood skirting.
Spas present more design options than hot tubs, ranging from straight-sided squares and octagons to circular, free-form shapes. Spas are available in a wide range of colors, and their sleek texture helps make them a distinctive design element in any indoor or outdoor setting.
Typical sizes are 5 to 6 feet across and 4 feet deep, although spas are usually narrower across the bottom because of their contoured seats. The support equipment and installation are similar for hot tubs and spas.
Both are available as complete, freestanding packages, or as separate components that require assembly. The simplest installation is at grade level on an existing slab, and the most involved are in-ground spas or elevated hot tubs. Most building codes require a building permit for either installation.
Installation Of A Hot Tub Or Spa
Installation techniques vary for different models of hot tubs and spas, but they all include the same basic features. The tub or spa must be well supported. Tubs require a solid concrete slab, usually 6 inches thick, if they are installed on the ground. The slab needs to be only slightly larger than the tub.
A freestanding spa should have the same type of slab, but if it is a sunken spa, excavate a hole, then backfill it with sand. If you install the tub or spa on a deck, add extra beams below the deck and at least four independent posts and footings to support them. They should be cross-braced as well.
The tub or spa should also be convenient to pipe hook-ups. At the bottom is a drain that is the primary outlet for a pipe that goes to the pump. Most pumps are centrifugal, and must be large enough for the size of the tub and number of inlet jets (usually ¾ horsepower [hp] for 1 or 2 jets, 1 hp for 3 jets, 1½ hp for 4 jets, and 2 hp for 6 jets).
The pipe is plastic, usually PVC or CPVC, and 1½ inches in diameter. The pump keeps the water moving through the pipe, which goes to the filter. Filters vary in their effectiveness.
Cartridge filters have membranes of paper or fabric and are the least expensive. Replace a cartridge filter every year or two. Sand filters work better, and the best filters use diatomaceous earth (DE).
The water must be heated as well as filtered. In some systems, the heater is in the same circuit as the pump, usually between the filter and the tub.
In other systems, water goes directly from the filter to the tub, and the heater is on a separate loop of pipes. Water circulates through the heater by convection, sometimes boosted by a small pump.
With either system, the heater is powered by gas, electricity, or solar energy. Models vary widely in their output of BTUs and the speed with which they are able to heat all the water in the tub.
Water jets require their own circulation system. The system includes a blower that introduces air into the pipes to create greater water pressure.
The pipes that connect various units have valves for draining or isolating different parts of the system as well as jets where the pipes connect to the tank. The system is usually closed; it is not included in the supply system of the house.
In some cases, where codes allow, the filtering system may connect to house plumbing with a certain type of valve that prevents backflow. Wiring for a hot tub or spa must be in strict accordance with local codes.
Electric heaters and most pumps are on their own circuits, usually 240-volt. Lights and auxiliary water-jet systems use c120 volts. GFCI (ground fault circuit interrupters) must protect all wiring, and switches must be specific outdoor types that are out of reach of anyone in the tub.