Wood Hot Tub FAQs

Q.  What are the Advantages of a Wood Hot Tub vs. an Acrylic Spa?

A.  Although acrylic spas are by far more prevalent today than wooden hot tubs, it was the wooden hot tub that began the experience of social bathing in America. Whether to purchase an acrylic spa or a wooden hot tub depends mostly on personal preference and each individual situation.

There are however many reasons for choosing a wooden tub over a plastic spa.
Because they are assembled on site, a wooden hot tub can be carried through any doorway, down stairs or through any other narrow access.  With a spa, you have a large one-piece vessel which can be unwieldy or impossible to move into its final location.

The vertical walls and greater depth of the wooden tub surround the bather with more water than would be found in a spa, so there is a greater effect of buoyancy in the hot tub. In addition, there is typically much more leg room since you can stretch out under the bench, and taller bathers are more comfortably accommodated.

The overall size of the hot tub, depth and diameter, can be customized to fit anything you can imagine. The exact height of the bench, and the location that the jets are installed are exactly as you like.

Because of a wooden hot tub’s greater depth, a smaller diameter hot tub will seat the same number of people as a larger plastic spa. For example, a 5′ round hot tub will seat as many people as a 7′ square spa.

And a smaller surface area means less heating expense.  Then there’s the natural rustic look of a traditional wooden hot tub. From an aesthetic point of view, nothing matches the appearance of a wooden tub.

Q.  How Do Roberts Hot Tubs Differ from Other Wood Hot Tubs?

A.  Thickness of Wood – Roberts Hot Tubs Western Red Cedar and Alaskan Yellow Cedar hot tubs have a finished thickness of 1-3/4″. While all hot tubs are constructed of what’s commonly called 2×6, other hot tubs frequently have a finished thickness up to 1/2″ thinner. Thicker wood provides more stability, less warping, more insulating value and a longer life.

Round vs. Flat Bands – Roberts Hot Tubs use bands made of 1/2″ cold rolled circular steel with a tinsel strength of 10,000 pounds. The bands are polyethylene coated and held together with solid steel lugs and stainless steel nuts to eliminate corrosion.

Flat bands, though quite attractive, greatly shorten the life of a hot tub. Water accumulating under a flat band can cause pockets of dry rot in as little as five years.

Bench Design – The unique bench design of Roberts Hot Tubs is completely supported from the side of the hot tub. Because the bench has no legs you can stretch out in comfort without the possibility of stubbing your toes or entangling your feet. The bench can be installed at the height of your choosing, or split into multiple heights to accommodate different people.

Quality & Power of Equipment – Roberts Hot Tubs uses “pool grade” equipment rather than under-powered or discontinued spa equipment.

Thicker & Better Insulated Covers – Roberts Hot Tubs was the first to design and implement the use of a 6″ thick tapered insulating cover with an insulating seal along the entire hinge.

These covers, that come with every complete hot tub system, have an insulation value of R-21 and provide up to 60% more insulation value than the “normal” spa cover.

Precision Manufacturing Process Makes for Easy Assembly – Technological advances in computer aided milling makes Roberts Hot Tubs easy to assemble. Proprietary manufacturing equipment produces allowable tolerances of less than 3/1000 of an inch.

This insurers that there’s no need to shave or alter the finished staves. It also eliminates searching through stacks of uneven staves trying to find one with the right specs so that you can finish assembling the hot tub.

Tub Bottoms – Our tub bottoms are thicker than most standard hot tubs which allows for better insulation, less chance of warping and prolongs the life of your hot tub. In addition, we computer stamp the exact placement of each stave on the bottom of the tub so you’ll get a perfect fit every time.

Tongue & Groove Staves, Not Ball/Socket or Flat Sided – Roberts Hot Tubs uses tongue and groove on the edge of our staves, while many tub manufacturers use cheaper and less precise methods of holding their staves in place.

It takes more time, patience and skill based on the numerous diameters of tubs requiring different angles on the sides of the staves, but it allows for better surface contact, a smoother finish and easier assembly. As an added benefit, the staves are self aligning and eliminates staves from splintering due to thin edges.

Strong Chine Joists – Roberts Hot Tubs sit on strong 4″ x 6″ chine joists rather than standard 4″ x 4″ chine joists. It would cost less to use 4 x 4’s, but the bottom edge of the tub would be so close to the ground that it could easily collect dirt and debris that could prematurely promote dry rot.

4″ x 6″ chine joists lift the tub high enough to allow for optimum air circulation and gives the tub additional ground clearance. The additional height also allows enough room to install a drain fitting in the floor so that when you do need to drain your tub, all of the water will drain out.

The bottoms of Roberts Hot Tubs are so thick that only 3 chine joists are required on tubs up to 6′ in diameter for proper support. Using 3 chine joists instead of the normal 4 or 5 makes installing and leveling your tub easier and faster.

Q. What are the Therapeutic Benefits of Hot Tubs?

A. Hot Water Hydrotherapy provides both physical and mental benefits for a wide range of aliments, injuries and good health in general. Hot Water Hydrotherapy is best described as the medicinal use of hot water for positive health benefits.

These health benefits come from the mechanical and thermal effects of water interacting with the body. Soaking in a hot tub improves circulation, and when properly equipped, can provide a powerful and soothing massaging effect on sore muscles and aching joints.

Stress is often the underlying factor of many ailments and a good long soak in a hot tub can do wonders for your mental and physical well being.

Unlike the limitations of plastic and acrylic spas, you can personalize the jets in a wood hot tub anywhere you want. We can concentrate the installation of the powerful jets to better suit your personal needs.

Whether it’s your legs and feet, your back or your neck and shoulders, you have the option of focusing on specific areas of your body or your entire body in general.

Q. Why is the Quality or Grade of Hot Tub Wood So Important?

A. Unlike plastic spas, the requirements necessary to build a quality long lasting wood hot tub are more extensive and much more stringent. Plastic is plastic, but each species of wood is different and they each have a unique set of qualities that may or may not make them good candidates for hot tub construction.

The type, grade and quality of the wood plays an important role in the life expectancy, beauty and maintenance of a wooden hot tub as well as your overall hot tub experience.

One of the most desirable and sought after qualities of timber for hot tubs is a clear, heart, vertical grain, but that’s just one of many properties that a timber species must possess to even be considered for use in high quality wooden hot tubs.

Natural resistance to decay is another top concern when choosing a species of wood to use for a hot tub. Different cuts from the same wood species, or even the same tree, can have vastly different rot resistance qualities.

The ability of the wood to properly swell is order to maintain water tightness is also an important consideration. The proper wood must also have an agreeable grain pattern to eliminate any possibility of warping, pealing, de-laminating or splintering. Needless to say, knots are not welcome and must be completely avoided.

Q. Does the Thickness of the Wood Make a Difference?

A. Absolutely! While other manufacturers finished thickness is as thin as 1″ – 1-1/4″, our wooden cedar hot tubs are a full 1-3/4″ thick. The extra thickness adds a much greater insulation value and over time there is much less proneness to warping and more importantly, dry rot. The thicker the wood, the longer the life span of the wooden hot tub.

Q. Are Wood Hot Tubs Difficult to Clean & Maintain?

A. Absolutely not ! This is another common misconception about wood hot tubs. In fact, unlike plastic spas, wooden hot tubs don’t crack, chip, blister, bubble, fade or stain. To clean a hot tub all one has do is drain the water and rinse it out.

If necessary or desired they can be gently scrubbed with a soft brush and a mild bleach/water solution . Also unlike a spa, wherein 8 to 10 inches of water remains, when you drain a wood hot tub all the water drains out.

Most people leave the outside of a wooden tub natural bare wood. As with any type of wood, over time it will naturally gray from the elements. If you choose to put a finish on the outside of the hot tub, the directions for that finish will need to be followed carefully and most likely reapplied annually.

Q. How Much Does it Cost to Operate a Wood Hot Tub?

A. The cost of operating a wood hot tub varies widely depending on the size of the tub, the climate, the configuration and equipment of the installation and the price of gas or electricity in your area.

What we can tell you is that heat rises and over 80% of hot tub heat loss takes place on the top. Wood hot tubs may hold more water than a spa, but due to the fact that a comparable sized wood hot tub has a smaller surface area than a plastic spa, they generally cost about the same to operate as a plastic spa.

To help reduce the heat loss and heat costs, we’ve developed a 6″ to 4″ tapered, fully insulating hot tub and spa cover with an R value in excess of R-22. We include this with all our complete hot tub systems and it reduces heat loss from the top of the hot tub by as much as 50% compared to the average insulated spa cover on the market today.

Q. Should I Get a Gas or Electric Heater?

A. There are generally two things to consider when deciding between gas or electric heat. The speed at which the water will heat, and the cost to heat the water. The smallest gas heater (100k BTU’s) heats more than twice as fast as the largest electric heater (11kW).

In general, this will only be noticed when you refill the tub with cold water, however, with the smaller electric heater (5.5kW) the system may need to operate for a longer than normal period of time each day to maintain temperature.

The cost to operate can vary widely as gas and electric rates greatly vary in different parts of the country. Typically though, natural gas will be much cheaper than electricity. Heating with propane tends to run about the same as with electricity.

You can roughly figure a cost comparison based on your power bill. In comparing a 100k BTU natural gas heater (82% efficient) with an 11kW electric heater (100% efficient), you’ll want to compare a “Therm” of gas (generally how natural gas is billed) with 24Kwh of electricity (1 therm natural gas = 29.3kW electricity, however gas heaters are only 82% efficient). Propane is typically billed by the gallon, and 1 gallon of propane is equal to 22Kwh of electricity.

Q. How Quickly Does the Water Heat?

The rate at which the water heats depends on two things. The size of the hot tub, and the size of the heater. Below is a chart, showing the size of hot tub, size of heater, and how many degrees per hour the hot tub will heat.

Gas Heat Electric Heat

100k btu 200k btu 5.5kW 11kW
5×3 25° 50° 5.5° 11°
5×4 20° 40° 4.5° 9°
5×5 17° 34° 3.5° 7°
6×3 17° 34° 3.5° 7°
6×4 14° 28° 3° 6°
6×5 11° 22° 2° 4.5°
7×4 10° 20° 1.5° 3°
8×4 8° 16°

Hot tub size…diameter x height Figures are based on covered, straight sided hot tubs, conical tubs will heat approx. 10% faster. Your “mileage” may slightly vary.

Q. Do Wood Hot Tubs Leak?

A. Wood Hot Tubs springing leaks is the #1 common misconception or urban myth among people that don’t own one.

Wooden hot tubs are supposed to leak ever so slightly for the first few days after assembly, but the amount of leaked water is generally not even noticed. After the first few days, the wood in your hot tub will have swollen properly and formed a tight seal.

After almost 40 years of manufacturing wood hot tubs, we can say that there are basically only two reasons why a well built natural wood hot tub would leak.

1. Overuse of Chlorine & Bromine – The overuse of chlorine & bromine sanitizers is categorically the #1 cause of leaks in wood hot tubs. Excess chemicals will attack and destroy the wood causing leaks.

This issue is easily avoid by using non-chlorine based sanitizers, ionizers or ozonators for hot tub sanitation and by not exceeding the safety levels of chlorine and bromine sanitizers.

2. Improper Tub Assembly – Leaks due to chemical overuse are much more common than leaks due to improper assembly. If your hot tub never seems to totally seal, then improper assembly is the most likely cause.

All of our hot tubs come with a comprehensive, fully detailed and easy to understand set of installation and assembly instructions. We find that the vast majority of leaks due to improper assembly come from installers that failed to read and follow the assembly instructions.

Q. Are Wood Hot Tubs Unsanitary?

A. This is common misconception #2. The fact is, wood hot tubs are no less sanitary than plastic or acrylic spas. When improperly sanitized, wood hot tubs and acrylic spas can both represent a health hazard, but there is absolutely no evidence whatsoever that natural wood is more likely to harbor more bacteria or micro-organisms than plastic or acrylic spas.

In fact, a university study of kitchen cutting boards found that while bacteria multiplied and prospered on plastic cutting boards, it quickly died on cutting boards made from natural wood.

It’s important to remember, that regardless of the material that your hot tub or spa is made of, proper sanitation is the key.

Q. What Accessories & Options Are Available?

A. You can find all kinds of options, upgrades, accessories and more just by browsing on our user friendly website. We asked some of our long time customers for their opinion and they felt that the following list of upgrades and options improved their overall hot tub experience the most and gave them the Biggest Bang for Their Buck!

1. Larger Pumps, Extra Jets – All 5′ and larger hot tub systems come with a 1-1/2HP, 240v, 2 speed pump and four massage jets. This is generally adequate, but adding more jets and a larger or additional pump made a huge difference in the amount of soothing massage and stress relief that their hot tubs provided them.

2. Air Blower System – The next accessory to consider is a Bubbler System. The bubbler, or air blower, blows bubbles through a small holes in a ring of pipe that is attached beneath the hot tub bench.

The effect it creates, sometimes called a Champagne effect, can be very soothing. The Bubbler System comes with a 1-1/2 HP, 240v compressor, along with additional plumbing and controls.

3. Larger Gas Heater Option – The standard gas heater provided with our hot tub systems is a 100k Btu gas heater. Larger heaters are a great option for those who hate waiting for their hot tubs to warm up or for those who want to be completely spontaneous and use their tub whenever they want to.

4. Upgraded Insulating Covers – There are two different types of covers that you should put on your hot tub. One is an inexpensive floating blanket that rests right on the water.

The other is an insulating cover which fits over the top of the tub. These two covers and the layer of air between them virtually eliminate surface energy losses and will pay for themselves in a short time, even on indoor installations.

Our complete hot tub systems come with a UV inhibited marine grade vinyl covered 6″ thick foam cover. Some of the available cover options and upgrades are wooden covers, aluminum covers, roll covers and upgraded insulating covers. Please see our section on hot tub covers for descriptions in more detail.

5. Low Voltage Lighting – Low Voltage Lighting Systems for hot tubs have become very popular and provide subdued lighting inside the tub. The light is supplied with a separate spa side switch and a set of five colored lenses to suit your particular mood. The colored lenses can be changed from inside the tub without any need to drain the water.

Hot Tub Installation FAQs

Q.  How difficult is it to assemble a wooden hot tub?

A.  Hot tubs are not at all difficult to assemble, at least ours aren’t. Our assembly instructions are written with the do-it-yourself installer in mind and take you step by step through the basic hot tub assembly process. No special tools or skills are required.

The computer accuracy we use in manufacturing our wooden hot tubs means that not only is there no need to cut or modify the final stave to fit, but the bottom is also computer stamped to indicate the exact placement of each stave (vertical side board).

We can generally assemble a hot tub, on site in under 30 minutes. Figure about 2 hours for the novice, a little less if you have some help.  Included with the complete assembly instructions is a phone number to call for 24 hour, 7 day a week technical assistance regarding installations.

We can also ship a hot tub fully assembled, but beware, this adds to the shipping costs and can be rather difficult to move into location on your site.

Q.  How easy is it to install a complete hot tub system ?

A.  Besides assembling the wooden hot tub (listed above), the complete system also includes the necessary equipment along with most everything else needed for a basic installation. While many people do hire a contractor to do the complete hot tub installation, a good many do the majority, if not the entire installation themselves.

The three more difficult aspects of installing a wood hot tub are, providing a concrete pad for the hot tub and the equipment, running the gas line to the gas hot tub heater (if so equipped) and running the electrical circuit to the time-clock.

Excluding these 3 aspects, installing a complete hot tub system should be just a weekend project for a “home handyman”.

All of the hot tub plumbing is accomplished by gluing together PVC piping, and the support equipment is shipped complete with everything necessary to install your system. The instructions included contain complete plumbing diagrams and a simple to follow wiring schematic. We even provide the PVC glue and a special mallet for assembling the hot tub.

Q.  What type of base is needed for the hot tub to sit on?

A.  A wooden hot tub needs to sit on either a deck engineered and reinforced to carry the weight, or solid concrete. Anything else could allow the hot tub to settle unevenly and possibly cause leaking.

The necessary thickness of a concrete pad may vary depending on different soil conditions. Generally a 3″ thick, wire reinforced cement pad on stable ground will suffice.

Footings may or may not be necessary depending on local conditions (freezing, rain, ground movement etc.). Consultation with a local concrete contractor is advisable.

Minimum Hot Tub Pad Size

Straight Sided Tubs

4′ Diameter —– 42″ x 42″
5′ Diameter —– 54″ x 54″
6′ Diameter —– 66″ x 66″
7′ Diameter —– 78″ x 78″ Conical Tubs
5′ Diameter —– 42″ x 42″;
6′ Diameter —– 54″ x 54″
7′ Diameter —– 66″ x 66″

Q.  At what distance can the equipment be placed from the hot tub?

A.  National building codes call for the equipment to be a minimum of 5′ from the hot tub, or separated by a permanent solid barrier so that the distance from the water line, around the barrier, to the equipment is at least 5′.

The maximum distance is limited only by your imagination and individual requirements. 20′, 30′ or even 50′ from the hot tub to the equipment is perfectly acceptable.

The only downside to the equipment being a great distance from the hot tub is that if the system hasn’t run for a few hours the water in the pipes will have cooled down. Jumping in the hot tub, then turning on the pump, you’ll feel the cool water coming out of the jets.

This is easily overcome by turning on the pump a minute or so before entering the hot tub. Additionally, if the equipment is further than 40′ from the hot tub, the size of the piping should be increased one size so as to not cause a reduction in jet flow and pressure.

Q.  What are the electrical requirements?

A.  The standard complete hot tub system, which included a gas heater and 2 speed pump, requires a 20 amp 240v circuit including a ground and neutral. If an electric heater is opted for rather than a gas heater, and additional 60 amp circuit is required for the 11kw heater, while a 30 amp circuit is required for the 5.5kw heater. Options such as an additional jet kit, or an air bubbler system require additional power.

Q.  What are the considerations for constructing a deck around a hot tub ?

A.  Many people design and build a deck around their hot tub. There are a number of things that should be considered and designed into such a deck. The decking should not run over the top of the tub, but should be flush to the top of the hot tub.

On round hot tubs a small gap should be left between the decking and the hot tub. ¼” to ½” is sufficient. The exception to this is oval hot tubs. In oval hot tubs, over time, the pressure of the water will try to round out the top of the hot tub.

Slight contact between the long side of an oval hot tub and either the decking or deck framing will prevent this.   Many people choose to have the top of the deck ¼” to ½” below the top of the hot tub. This helps to prevent dirt and debris on the deck from blowing into the hot tub.

An additional consideration is future access to the exterior of the hot tub. At some point in the future the exterior of the hot tub may need to be accessed for inspection, maintenance or possible for repairs.

Dirt and debris should also be cleared out from around the sides and bottom of the hot tub. If a deck is going to completely seal in the hot tub, screwing down the decking, or providing a trap door or other type of access is advisable.