Installing Your Own Spa
- The Good Life -
How to install a hot tub in your backyard
TEXT AND PHOTOS BY MERLE HENKENIUS
You don't need to spend much time luxuriating in a hot-tub spa to discover its relaxation benefits. And while you'd expect all that warm swirling water to be soothing, it can also work wonders on sore muscles and joints and it's a great all-around stress reliever. Backyard spas are ideal for families on the go. They can slow us down, help us refocus and drain away the tensions of the day - all in about 20 minutes.
Hot tubs are not for everyone, however. All those warm, massaging bubbles can raise blood pressure and heart rates, while decreasing blood sugar. As such, they're not recommended for infants, the very old or those with diabetes, hypertension or heart disease.
Choosing Your Tub
Shopping for hot tubs can be a little confusing. There are so many brands and models, and every salesperson seems to highlight a different set of features. As usual, price is a good indicator of quality. Spas range between $1500 and $10,000, with the better models starting around $3500. These are three- and four-person tubs. Larger spas cost more, and those with lots of specialized jets, DC-powered pumps and ozone-generating water purifiers, can soon reach $6000 to $8000. Add accessories and you can easily pay a couple thousand more.
A few companies offer two-person spas, but most start with three- or four-person seating and go up to the eight-person size. At least one lounge seat with back and neck jets is typical. Four-person models measure about 5 x 6 ft., and are roughly 30 in. deep. A full-size tub can measure 8 x 8 ft. and 42 in. deep. Big tubs are great for large, active households with plenty of space, but smaller tubs are no less appealing or therapeutic.
Large tubs can also limit your placement options. Filled with water, a full-size tub can weigh 5500 pounds - more than most conventionally framed floors and decks can safely manage. If you can't beef up the floor, you'll either need a smaller tub or an installation on concrete. Your spa dealer and building codes office can help you work through the options.
Most spa shells these days are made in two layers: a reinforced fiberglass base and a formed acrylic shell laminated over it. Fiberglass brings strength, and acrylic adds durability and more color and texture options. The shell is piped and fitted with pumps and jets, and is insulated. The shell is free-standing, so the wooden skirting is largely decorative, though it does conceal and protect the machinery.
Most spas are wired with 240-volt electrical equipment and some include DC converters. DC motors run more quietly and DC circuit boards are very reliable. A few economy tubs are available with 120-volt circuitry to make the electrical connections easier - you just plug these models in. However, these tubs are small, their heaters are less efficient and they shut down when the jets are turned on.
Companies typically offer 10- to 20-year warranties against leaks through the shell, but these types of leaks are unlikely given the thickness of the laminations. More probable are surface problems such as blisters, cracks and discoloration. Look for a five- to seven-year surface warranty and three- to five-year protection on the pumps.
The spa we chose is a Jacuzzi Triton - a large model with all the bells and whistles. Powered by two 4-hp DC pumps, it sports 42 jets - 10 fully adjustable and 16 directional, 10 air injector jets and a set of lounge jets that offer full back massage. Other features include a remote control for the tub operation, an AM/FM/CD player, underwater lighting, four headrest cushions and dual waterfall fixtures. Most importantly, it includes a built-in ozone generator and a water purifier that saves time and money by reducing the amount of chemicals needed. At 42 x 91 x 91 in., it's not the largest tub, but it comes close. Jacuzzi's Triton has a sticker price of $10,000, but typically sells for less.
Locating The Tub
Our backyard is small, extending only about 20 ft. beyond a large deck. The grade also steps up about 2-1/2 ft., roughly 10 ft. away from the deck. To fit the tub, we cut away some of the bank and built a small retaining wall. When deciding where to place your unit, keep in mind that spas need service access on all sides.
|We planned for one side of our tub to be 18 in. from our deck, then measured out the
width of the tub plus an additional 18 in. to establish the face of the new retaining
wall. To accommodate the depth of the retaining-wall blocks, plus a foot for drainage
gravel, we cut into the bank an additional 24 in.
To build the retaining wall, first dig out the bank. Using some of the removed soil, grade the installation area just enough to allow drainage away from the tub. For the first row of landscape blocks, excavate a trench about 4 in. deep and fill it with pea gravel or crushed rock.
Level the gravel and compact it with a hand tamper or gas-powered sand-plate tamper. String a level line to guide the first row of blocks. Use a 4-ft. level to make sure the course is level (Photo 1).
|With the first course in place, set the remaining blocks. The type of block we used has a lip along the back edge that locks over the block below. When turning a corner, you'll need to break off this edge to maintain the same setback between the courses. To keep these blocks from sliding forward over time, glue them in place with masonry construction adhesive (Photo 2). When you finish the wall, backfill with gravel. Cover the top of the gravel with weed-guard fabric and soil.||
|Next, set the form lumber for the concrete pad, and level it in all directions. Check
that the form is square by making sure the diagonal measurements are equal. Spread sand
inside the form to fill any voids and tamp it. Fill the form with concrete and screed it
with a straight 2 x 4. Then, float and trowel the slab smooth (Photo 3).
While an adequate pad might consist of 2500-psi concrete, beefed up with iron rebar or wire mesh, local electrical codes would have required us to ground this reinforcing metal back to the electrical service panel. To avoid this problem, we upgraded to 3000-psi concrete and added fiberglass reinforcement to our 4-in.-thick pad.
We moved our tub from the driveway to the site on a small trailer. Carefully slide the tub off and position it on the slab.
Setting The Tub
If you buy your hot tub from a spa dealer, the company will usually set it in place for you. If you buy through a home center or discount store, however, you may need to move and install the tub yourself. Large tubs weigh close to a thousand pounds, so this can seem a daunting task. With five or six friends and a small trailer, however, it all becomes manageable. Assuming your tub is in a crate in the driveway, remove the packing and slide the tub onto the trailer. Then, wheel it to the site and carefully slide it onto the concrete pad (Photo 4). If you need to pass through a gate or narrow side yard, stand the tub on end atop a furniture cart. The right side of our tub, as you face the front, is built for upright travel.
Water and electricity don't mix, so if you're not comfortable with your wiring skills, this is a good time to hire an electrician.
In our case, local codes required a continuous bond wire from the tub to the service panel. This is in addition to the electrical ground. Codes vary on this point, so be sure to ask your local inspector. We also needed a disconnect box at least 5 ft. from the tub and a GFCI breaker protecting the entire circuit.
Because of the DC converter, we used only two hot wires, a grounding wire and a bonding wire - no neutral was needed. Our spa was close to 70 ft. from the service panel, so we ran 6-ga. stranded wire for the two hots and the ground wire, and an 8-ga. bond wire. While all outdoor wiring needs to be in conduit, we decided to install the entire run from the main panel in 1-in. PVC pipe.
|Begin by running the conduit from the service panel to a house rim joist near the tub. Bore through the siding and the joist with a hole saw (Photo 5) and feed the conduit through the joist.||
|Glue an LB conduit box to the conduit and extend the conduit up to a disconnect box. Dig a channel at least 18 in. deep for the buried conduit from the tub. At the tub, join an LB to the conduit with a slip coupling to allow the ground to shift seasonally without stressing the conduit connections (Photo 6). We carried the conduit underground to our deck. Here, we brought it up to the deck with another slip coupling and LB, and then ran it to the disconnect box.||
|With the conduit in place, pull the four wires from the main panel to the disconnect box with a fish tape (Photo 7).||
|Then, pull them between the disconnect box and spa. Bind the hot wires to the hot terminals (Photo 8) and the ground wires to the ground terminals. In our case, it was required that the bonding wire continue uninterrupted through the disconnect panel. Mark the ground wires with green tape. Then, install the disconnect box and LB covers.||
|Finish the outdoor wiring by making the hot, ground and bond connections in the spa's equipment box (Photo 9). You'll find the terminals clearly labeled.||
|Finally, connect the circuit hot wires to a 50-amp GFCI breaker in the service panel (Photo 10) and connect the bond and grounding wires to the panel's grounding bus. Leave the circuit's power off until after you've filled the tub with water and your work has passed inspection.||
To make steps for our hot tub, we first poured a 31-in.-wide concrete pad, and then built two 30-in.-wide step boxes out of cedar. Make the box frames out of 2 x 6 lumber. Size the depth of the bottom box for two 2 x 12 treads, and the depth of the top box for one 2 x 12 tread. Assemble the boxes with screws (Photo 11).
|After the bottom box is built, secure the top box frame to it with screws driven diagonally from the inside (Photo 12)||
|Then, add the top tread (Photo 13) and stain the assembly to match the skirting.||
|To secure the spa cover, set it in place and straighten it. Hold the bottom portion of each clasp in place and secure it with the screws provided (Photo 14).||
|Finally, install the polyester filters in the filter housings (Photo 15) and fill the tub with a garden hose.||
|Insert the hose into one of the filter housings and tape it in place (Photo 16). Expect the tub to fill in about 45 minutes.||