Round wood hot tubs enjoyed popularity in the
1970s, but had largely disappeared by the late eighties. Although a
handful are still made to this day, modern self-contained portable
spas have for the most part replaced them in the evolution of hot
We're often asked to explain the difference
between a hot tub and a spa. Spas, typically rectangular in shape,
are larger and made of acrylic or a similar durable, lower maintenance
material, with advanced water features, jetting, and purification
systems. It's really a matter of semantics: all spas are hot tubs, but
wooden hot tubs are not
normally referred to as spas.
Construction of Wooden Tubs
Wood hot tubs, often made of redwood or cedar,
are assembled from many vertical boards called staves .The edges of
the staves, which look like a standard 2 x 4, are angled so that when
the staves are assembled edge to edge, the result is a round vessel.
The bottom of each stave is carved with a groove called the croze
which fits to the width of the floorboards.
||The flooring is constructed of horizontal
planks. One edge of each floorboard has two or more holes
drilled in it and the other edge has corresponding pegs. The pegs make
assembly easier by keeping the floorboards properly aligned. The ends
of each floorboard are curved slightly, with the center floorboard
being the longest and with each of the succeeding floorboards on either side
being slightly shorter. The final result is a round, flat floor surface.
The entire structure is held together in the
same manner as round wooden barrels. The staves are strapped in place by
several round metal bands, tightened with nuts.
||Wooden tubs use a lot of lumber to
manufacture. As the noble forests of North America have dwindled over
the years, supplies of quality redwood and cedar have fallen,
and the suitable grades of wood for hot tubs has been on a steep decline.
This has forced prices up, as the quality of available lumber has gone
A major disadvantage of wood hot tubs is lack of
comfortable seating. Lounge and bucket seats obviously cannot be molded into
wood as they can in an acrylic spa.
Standing upright in the water, or
sitting on wood plank benches are the main seating options in these tubs.
Jets & Hydromassage
Just soaking in hot water can have therapeutic
benefits, but the vigorous jet action of modern contemporary spas,
which mix air and water for stimulating hydro-massage of the entire
body, is at least half of the experience. By comparison, the
water circulation of wood hot tubs
might seem primitive to you, although jets can be added.
||Since wooden tubs do hot have a protective, insulated cabinet
like portable spas, any jet plumbing and water circulation pipes
must be mounted on the outside of the barrel. Aside from
the lack of aesthetic appeal, external pipes can freeze and break
in cold weather. Since the tubing cannot be properly
insulated, a huge amount of energy is lost as well.
Prepare for Higher Maintenance
Like wooden boats, wood hot tubs can be
esthetically pleasing. The other factor that they have in common with
wood boats is high maintenance. Unlike acrylic spas, wood tubs
require a break-in period. Wood tubs leak when first put into service,
and during break-in time must be allowed for the wood to absorb water, swell,
and seal the cracks between the staves.
||Two of the common woods used in hot tubs are
redwood and cedar. These woods contain naturally-occurring toxins
which to a limited extent help prevent the wood from rotting. These
compounds leach out into the water, especially in a new wood hot tub.
Bathing is not recommended until the tub has been drained and
refilled with fresh water, perhaps several times during the break-in period.
< Well broken-in wooden tub
Owners of wood hot tubs should be prepared for a
lot more periodic maintenance than acrylic spas require. We believe
this is the primary reason that their popularity dwindled so
dramatically after modern spas were introduced.
Leaks are the Norm
Wood hot tubs are much more prone to leaks than spas, in part because
there are so many more places for water to leak from. The planks must
never be allowed to dry out (and shrink) from low water level, or
leaking problems will definitely develop.
||Freezing weather can
cause moisture in the wood's cell structure to expand, microscopically
breaking the fibers apart, eventually resulting in cracks as shown
here. Exposure of one side of the hot tub to
direct sunlight in the hot summer sun, while the other side is shaded
and cooler, can sometimes cause warping, which is another cause of
|Termites & Carpenter Ant Infestation
Over time, even durable woods like heart redwood will rot and
disintegrate as a result of both microorganisms and vermin.
A wood hot tub is an appetizing target for
carpenter ants which are attracted by the moisture, and termites too, especially if there is ground contact.
These pests can devour the structure.
Wood is a naturally porous material, and
love to hide and multiply in the microscopic nooks and crannies.
Unfortunately the conventional disinfectants, bromine
and chlorine, not only oxidize bacteria, they also break down the wood
itself. For this reason, most local health codes prohibit wood hot
tubs for public or commercial use. The risk of disease being spread to
the public is considered too great because bacteria held in the wood
can easily be transmitted to others.
||If you already own a wooden hot tub or are
getting one, consider a friendlier alternative sanitizer such as
Blue sanitizer. It's an EPA registered copper ion based
bactericide & algicide-- a technology which does not rely on harsh
bromine or chlorine to purify the water.
Wood Decomposition Problems
The effects of chlorine and bromine can strip
lignin out of wood. Lignin is a pulpy white cellulose substance which
binds the organic structure of wood together. Over time, the tub will
look as if to be growing a milky fur on its interior surfaces which
can clog filters and cause a lot of other messy sanitation problems.
||The only solution to this recurring maintenance issue is to drain the
tub, allow the wood to dry out, and then sand all of the interior
surfaces by hand using coarse, then finer sandpaper until it has been
removed down to hard, sound wood. Then the tub must be refilled,
allowing time for the water to re-swell the dry wood to reduce
Algae Contamination in Porous Wood
Algae blooms can also be a serious problem in
wooden hot tubs. The common method to deal with this issue is to
superchlorinate the water and hand brush all of the affected interior
wood surfaces with a stiff brush. This forces the chlorine below the
surface where the algae is rooted. The process often has to be
repeated several times, completely draining the water each time, until
the algae is eradicated and the tub disinfected. Proper sanitizing
Although wood itself has some insulating
properties, it loses most of its R-value when it becomes saturated
with water. Because heat retention is such a major shortfall, a
cover is essential and will help to mitigate some of the expense
of this wasted energy.
hot tubs use a lot more energy to maintain
their temperature than today's super-insulated, low-maintenance portable spas
such as our quality
spa line (pictured right).
Beautifully durable LifeCast Spas are now more affordable than ever before!