DIY Hot Wood Fired Tub +20 for Relax in Garden

by woodenProjects

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Intro: DIY Hot Wood Fired Tub +20 for Relax in Garden

Everyone likes hot baths, but what about having them in Your garden, when You see the sunset or the stars at the sky ? That's an idea!

I'll show You how to built really simple hot tub in the garden/backyard. You can think about it as cheap jacuzzi ;-)

The project isn't hard, although time consuming, because You need to wait few days when the foundations will dry, the plastering will dry etc..


STEP 1: The Idea and a Tub

Hot tub construction should be safe and looking good to fit to the rest of the garden. In My garden there are lot of white elements, so I decided to have white frame for a bathtub.

The tub should be made from metal - steel or even iron - from obvious reason. It will be heated from the fire underneath it. The fire will be close and not visible from the outside (safety reasons, kids in the garden). I don't want to build the chimney because it would not fit to the rest of my garden/it would be to heavy construction). So, the entrance to the fireplace should be big enough to sustain fresh airflow for a fire and smoke outflow from the fire.

STEP 2: Foundations

I recommend to build pretty strong foundations. The brick frame will be heavy and when You put the tub on it, feel with many, many liters of water, it will be considerable heavy. To avoid the cracks, and tensions I recommend to make the steel reinforcement of the foundations.

To build foundations You need to dig a hole (30 cm is enough), put a wooden frame around it and make the reinforcement from the steel. Remember that steel has to be inside the foundations so put it on the stones (not on the bricks, because bricks in time will crack and the water will erode the reinforcement).

The frame is not only for the rectangular shape. It allows You to level the concrete surface.

STEP 3: Oven and the Chimney

I started the build from making the oven from the special bricks placed with the special mortar. Bricks and mortar are temperature resistant, they won't crack in fire. Moreover, such bricks can accumulate the heat - it's very good, because even when the fire would be over, the heat from the bricks will be steel heating the water for some time.

The purpose of the oven inside the frame is also, that it's wall will protect the normal, red bricks from the heat.

As I mentioned, there will be no chimney. So the entrance for the oven have to be big to allow air to go in and smoke to go out.

In my case, the entrance has about 50x50cm. This works great.

STEP 4: Bricklaying

Bricklaying seems to be something hard, but.. it isn't. You just need to keep the track of the level and the straight of the walls, so if You will use the leveling tool often - the construction will be ok ;-)

The weld between the bricks don't have to be perfect since the bricks will be later covered with plaster.

To make the roof for the oven entrance I used the frame from the boards and the mortar made from the cement, lime and some addition of heat resistant mortar. I also reinforced it with three steel rods.

STEP 5: Plastering

Plastering is the hardest thing to do. It looks easy, but in fact it could be iritating if You don't know how to do it.

The most important thing is that the mortar (made from cement, lime and sand) should not be to wet. It should hold to the walls and that's all. If it's to wet it will fall down.

After putting the mortar on the walls You need to wait some time, it will dry a little bit and then it's ready for flattening with Styrofoam float.

Oh, one more thing, before plastering You need to throw at Your walls the mortar to have 'bumpy' surface. The plaster will then have better grip.

STEP 6: Painting With Paint Ant the Ground

When plaster is dry, put the 'ground' on it. This is the white liquid which is the first coat before the paint.

It's application is for two reasons:

- it will close the pours and microscopic holes in the plaster, so the further paint will have better grip

- it will protect Your walls from soaking water and from cracks during winter

After protecting Your walls, they are ready for painting. Use any colour You want and the paint for the outside

STEP 7: Tub Montage

To mount the tub I used mortart and two kind of silicones.

I put the fresh heat resistant mortar on the top bricks in the oven, then I put the heat resistant silicone(black one) on the top of the frame walls. Next I put the tub on the frame so it fit's to the mortar on the oven and glued to the frame with a silicone.

The last step, for protection, was to put the water resistant silicone along the tub

STEP 8: The End - the Relax :)

That's all !

Now You are ready for the bath in the hot water at Your garden/backyard. Enjoy it:)

One more thing. Don't put the big fire, because even the small one is enough to heat several hundreds liters of the water in quite a fast time. Really! This construction is so efficient that I'm able to rise the water temperature for more than 20 degrees in just 35-45 minutes.

50 Comments

blkhawk 4 years ago

I had a nice old steel tub that I regret scrapping now. Great project!

compmend 4 years ago

Here in Florida we would have thousands of mosquitoes and maybe a couple of water moccasins wanting to share the bath with us. It is a really nice project though. I guess if you made something like that here, you could put a tent of some sort over it.

ooohlaa 4 years ago

Ya I am in FL and the mosquitoes are killer even in North Central FL. There is just about a 3 week winter period when they are dead. I saw a pop up tent that is all mosquito net on Amazon. That could work. Some have floors and some do not or you can cut out the moquito net floor. I love my outdoor shower I heat with Eccotemp propane heater, it has hose connection and could easily be used to fill the tub without fire. I have been wanting a tub for 20 years since I moved here from Hawaii and had the japanese soak tub made out of slate.

Mimikry 4 years ago

really interesting ...
I also have an old bathtub in my backyard to enjoy a hot bath while surrounded by nature :)
Until now I cooked water in a big kettle on a wooden fire -but thats kind of dangerous and not very elegant...
I'll think your solution through - but I might add a chimney anyway - cause smoke in my eyes while taking a bath sounds unpleasant… - and I would have to keep the fire alive while bathing - I like to take a bath for 2 hours or even longer if I have a good book and one or two glasses of wine :)
I'm also thinking of two bathtubs next to each other - for long philosophy nights ;)
Thanks for your instructable!

ooohlaa 4 years ago

what about using an Eccotemp propane water heater that has hose connections I have one in outdoor shower and it works great, water can get very hot. Maybe also build an insulating wall around the tub but I would miss the claw foot ambiance. BTW I thought clawfoot tubs were the designer rage and sold for like $2K and hardly available? Maybe just here in FL?

woodenProjects 4 years ago

You are right about the smoke, but You have two sollution:
- big chimney
- make fire, fire will heat the water&special bricks, wait until fire is gone and then make a bath with no smoke at all.

smoke is also good for mosquitos:)

manicmonday 4 years ago

Direct heat on your tooshy could cause unpleasant burns.

JP673 4 years ago

By glass’s I hope you mean bottles!?!? #LifeIsGood

GrahamH27 4 years ago

How do you fill and empty the bath please

woodenProjects 4 years ago

filling - with the water from garden pipe/sneak (i dont know exact word in english)
empting - with an outflow on the bottom of one wall

GrahamH27 4 years ago

Hi. We call them hosepipe

Grah

ewbray 4 years ago

Why not just go to a Salvage Yard buy an "old" claw foot tube and make a "poor man's" Scandinavian 'hot tub' something like the attached images by drilling a few holes in the tub and maybe a surplus 35 or 55 gallon drum. It even can be moved to match the outside seasons if you live in a temperate climate!

woodenProjects 4 years ago

this is not the best idea in my opinion.
- the efficiency is poor, You have to wait several hours (on forums people say that from 4 up to 7). In my project it takes only 30-60 minutes
- You have open fire which is not good when the kids are in the Garden
- You have the complicated design (how to drill in thick steel, how to secure it from water etc)

ewbray 4 years ago

Here is a "perfect" oversized "old" Claw Foot tub from Philly Salvage with straight side that would accommodate a M67 military surplus immersion heater and still have enough area to partition off the M67 military surplus immersion heater from the tub's occupants. Cost of tub ~$300.00 to ~$500.00 or what ever you can bargain or haggle it down to; Cost of M67 military surplus immersion heater ~$140.00. There are plenty ads of people renovating old houses that want to get rid "old" Claw Foot tubs.

Jobar007 4 years ago

Having the tub in contact with the fire doesn't create a hot spot in it?

woodenProjects 4 years ago

Yes there are hot spots, but water quickly takes the hot from them.
If You put very big fire it's impossible to seat on it. Then I'm using the sit made from sponge pillow.
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