Wooden Hot Tub FAQs

How often should I change the water in my hot tub?

You should change water in a domestic environment every couple of days. If there are lots of different bathers and intensive use, you might want to change it every day. If you’d prefer to leave the same water in the tub for longer periods of time, we recommend installing a filtration system.
Please note, when not in use, never leave your tub empty of water.

How do I clean my wooden hot tub?

We recommend only using natural cleaning products. Depending on the manufacturers instructions, add disnfectant to the hot tub about an hour before emptying. While the timber is still wet (you can wait for it to drain, or start during draining) scrub all acessible areas with a soft brush or sponge. Rinse thoroughly

Are they difficult to keep clean?

No. It’s a myth that hot tubs go all green and slimy. This only happens if you really don’t look after them. Wood has a natural, mild antiseptic in it so as long as you follow our simple maintenance instructions you’ll have no problems – and it doesn’t take much effort.

How long do wooden hot tubs last?

With good care, a cover and maybe a yearly coating of Danish Oil (or similar) on the exterior, it will last indefinitely. The tight-grained, naturally seasoned Douglas fir that we use doesn’t rot easily. In short, in optimum conditions your tub will last for many years.

Why doesn’t the hot tub leak?

This is our most commonly asked question. The truth is, it does at first, but as the water swells the wood, all the joints close up forming a watertight seal.

How long does the water take to heat up?

About one to four hours, depending on tub size, the surrounding air temperature and the quality of the firewood used. Stir the water every now and then to get an even spread of heat.

Is it noisy?

Not at all. An occasional crackle from a log and snap of a log and light rumble from the flame in the flue is all you hear. It just adds to the atmosphere…

Is it smoky?

There is some smoke until the wood gets up to optimum temperature. After that, there is very little – if you use dry wood. The smell of a wood fire is wonderfully romantic and again, part of the atmosphere.

Can I use any type of wood or other solid fuels?

No. Only dry wood. Don’t use solid fuels or fresh, green/wet wood.

How much fuel is used per session?

Wood-burners are very fuel efficient and our timber tubs insulate the water. So, you need about two bags of dry logs to get the water up to a good temperature and keep it there while you bathe. Once you’ve heated your hot tub in the evening, it will still be hot enough to get into the next morning if you keep the lid on.

How often do I have to clean out the boiler?

Every now and then. Wood burns fine on a bed of ash. You don’t have to clean it completely out either, just enough to ensure air flow. When you do clean it out though, make sure the embers have died out completely and use a long-handled shovel.

What should I do with the ash?

It’s great for your garden. Compost it or mix directly into your soil.

Does the wood fade?

Douglas fir ages naturally to a slightly silvery colour. You can deepen colour by adding suitable oils (only to the exterior) such as Danish Oil


Cashen wins 2014 Royal Cornwall Show Forestry Competition

Against stiff competition, we won this great award for the quality of our hot tubs. Here’s what the judges said:

'Jeremy Cashen's business based near Menheniot, produces hot tubs, saunas and garden structures from locally grown Douglas fir. Not only does Jeremy manufacture all his products, he also harvests, transports the timber, mills it and then kiln dries it. This demonstrates an exceptional level of vertical integration to ensure high quality products which showcase the beauty and versatility of cornish timber.


Each aspect of timber processing and manufacturing is undertaken with great efficiency using low cost but effective machinery. A four-side planner is at the heart of the manufacturing process, and adds sufficient value to make the whole process worthwhile. We hope his customers appreciate the skill and commitment which goes into Jeremy's products.'

Find out more about the care we put into our hand-crafted hot tubs, gazebos and saunas. Call Jeremy on 07710 257 834.

Cashen keeps them warm at The World Belly Boarding Championships.

100s of competitors braved the waves on 2nd Sept at Chapel Porth Beach, St Agnes in Cornwall. Conditions were ‘lively’ and some got a bit more than they bargained for, including comedians Rory McGrath and Will Mellor. But at least they had our steaming hot tubs to welcome them in from the cold.

>> See Rory McGrath & Will Mellor in Cashen hot tubs on Facebook