Wooden Hot Tubs: What to Know Before You Buy One

A wooden hot tub is any outdoor tub with a wood exterior, and there are two very different things inside that exterior. In a traditional all-wood tub, the wood is the vessel: staves bound by bands, sealed by swelling. In a wood-sided tub, the wood is cladding over a structure of another material, and the structure is what holds the water. Both look like wooden hot tubs from the lawn. They behave nothing alike over ten years, which is why the first question to ask is what is holding the water.

This guide covers the types, the woods, the heating, the care, and the questions worth asking any manufacturer before buying one.

The two kinds of wooden hot tub

All-wood, or stave-built

The original. Vertical boards, usually cedar, held in a circle by steel bands, with a wooden floor. There is no separate vessel; the wood is the tank. It seals only because the boards have absorbed water and swollen against each other, which is also its central limitation. Leave it empty and it dries, shrinks and leaks on the next fill until the wood swells again. So an all-wood tub is kept full, which means standing water to treat, growth in the grain that a rinse does not reach, and a freeze risk in winter because draining is not an option. It is beautiful, and it is authentic, and it asks for constant attention.

Wood-sided, or wood-clad

The wood is the exterior finish, the seating and the lid, and the water sits in a structure made of something that does not move with moisture. That structure can be fiberglass, plastic, stainless steel or aluminum, and the choice matters as much as the wood. An AlumiTub is a riveted marine-grade aluminum structure clad in Canadian Western Red Cedar: it holds water without depending on the wood, so it can be drained between visits and left empty for the winter, filled from a lake or the ocean, insulated on every side, and moved by two people at 200 to 300 lbs. Every hot tub material compared sets the structures against each other, including where aluminum is not the right choice.

The wood itself

Western Red Cedar is the standard for good reason: naturally rot and insect resistant, dimensionally stable for a softwood, one of the better insulators among North American timbers, and it smells the way people want a wooden hot tub to smell. Thermally modified woods and some hardwoods appear on imported tubs; ask what species and where it was milled, since "Canadian cedar" describes the wood, not where the tub was built. Why AlumiTubs use Western Red Cedar covers the wood, and ours is milled by a neighbor on the Sunshine Coast from trees that have already fallen.

Whatever the species, outdoor wood silvers to gray over a couple of seasons. That is weathering rather than failure. It can be left, sanded back, or finished with a stain or clear coat, copper-free on any tub with an aluminum structure. On a wood-clad tub a board that weathers badly is replaced on its own rather than the tub being rebuilt.

How wooden hot tubs are heated

Wood fire is the traditional match and still the most common: a firebox submerged in the water, or an external stove with a circulation loop, heating from cold in a few hours with no electricity. Electric heating with filtration suits daily use at home and guest properties. A hybrid carries both. Gas and solar exist but are rare, and neither is offered on an AlumiTub. The heating options guide compares wood fired, electric and hybrid side by side, and on an AlumiTub the heating can change later rather than being decided once.

Living with one

• Water. An all-wood tub holds water continuously and needs a treatment routine to match. A wood-clad aluminum tub can be filled and drained around each visit with no treatment at all, or held for weeks to months with light water care and filtration. Either way the ranges are the same: alkalinity 80 to 120 ppm first, pH 7.4 to 7.8, calcium hardness 150 to 250 ppm, bromine 2 to 3 ppm if water is held.
• Winter. An all-wood tub must stay full and above freezing. An aluminum-structured tub is drained and left empty, or run through winter, or on an electric or hybrid held by freeze protection. Can you use a wood fired hot tub in winter covers both.
• Cleaning. Wood grain harbors growth and takes a brush. A smooth aluminum interior takes a soft cloth and a mild plant-based cleanser, never vinegar or abrasives.
• Moving it. An all-wood tub is assembled in place and stays there. A pre-assembled cedar-clad aluminum tub rolls on its side through a 38 inch gap.

Six questions to ask before buying a wooden hot tub

1. What holds the water: the wood itself, or a structure underneath it, and of what?
2. Can it be drained and left empty without consequence?
3. Where was the tub built, as distinct from where the wood came from?
4. How is it insulated, and where: the walls, the base, the water surface?
5. Does it arrive assembled, or as a kit, and who is responsible if the assembly leaks?
6. What is the warranty on the structure, in years, and who honors it?

The answers separate a wooden hot tub that is still in use in twenty years from one that is firewood in five. Five things most buyers never know about cedar hot tubs goes deeper on the points that catch people out.

Common questions

What is a wooden hot tub?

Any outdoor hot tub with a wood exterior, usually Western Red Cedar. In an all-wood tub the staves are the vessel, sealed by swelling. In a wood-sided tub the wood clads a structure of fiberglass, plastic, stainless or aluminum that holds the water, which decides how the tub behaves over time.

Do wooden hot tubs leak?

All-wood tubs seal only while the staves are swollen, so they leak after being left empty and can develop leaks as the wood moves over years. A wood-clad tub with an aluminum structure holds water without depending on the wood and can be drained and left empty.

How long does a wooden hot tub last?

It depends on what holds the water. All-wood tubs can last many years with constant care and never being left empty. A cedar-clad tub on a marine-grade aluminum structure carries a 25 year structural warranty, with replaceable cedar and owners at nearly twenty years of use.

Can a wooden hot tub be left empty?

Not an all-wood one, which dries, shrinks and leaks on the next fill. A wood-clad aluminum tub can be drained after a weekend and left empty for the winter with no consequence, which is what makes it workable at a cabin or a rental with gaps between visits.

Are wooden hot tubs hard to maintain?

All-wood tubs ask for continuous water treatment, band tightening and management of the wood's movement. A cedar-clad aluminum tub asks for four water readings a couple of times a week if water is held, a wipe with a soft cloth, and optional stain on the exterior every year or two.