Tuesday, August 29, 2017

short summer series. hot tub time (machine)!

This project began somewhere in March. Okay, maybe that is not entirely true: it actually began when I was sixteen years old, when my big brother -the most inventive engineer I know- crafted a wood burning stove with a water heating system to warm up our inflatable kiddy pool. Due to the enormous succes of the invention, he and my dad quickly replaced the inflatable pool by a more durable tub made from something that was previously used as a cattle watering tub, and hence the first DIY hot tub of our family was born.
When I first took Joost to my parents' house, and showed him the hottub made by my big bro and my dad, he immediately responded: "We should totally make something like that!

The idea lingered, and when we bought our house last year, one of Joost's first questions was: "shall we build a hot tub in the garden?"

Forwarding a few months to March, when Joost restated the idea: "we really should build a hot tub, it would be awesome for next summer!" He was right, and plus: we really had a corner in our garden that was in dire need of a bit of some serious redesigning:

"I don't see your problem with it, human" 
Okay, maybe Lieve liked it as one of her famous chilling spots, but we really didn't.

So, with my family's hot tub design in the back of our mind, we set to work.

We bought an old IBC container online. For those of you who don't know it - I didn't- an IBC container is a reinforced container used to store great amounts of liquids. It's strong, watertight and conveniently comes with a drain.  We made sure to ask that it hadn't been used for harmful chemicals, since it would possibly ruin the bathing experience a bit if chilling in the hot tub would make our skins turn green.

something like this! 
The container was about 40 euros.
At home, Joost got rid of the top bars, as well as the top part of the plastic container within, While I did some serious digging in the garden ( you know, for reasons), and finishing the shed we build, which you can see in the background of the photo.

Next up was a heating system.

like the one at my parent's house, we basically wanted a firewood stove, with a heat exchange unit in it, where you would pump the water through to heat it. To comprehend what I'm on about, this is what it looks like in schematics:

Now, While my big bro built the whole thing himself, made from parts he bought at the scrap heap and welded it all together, neither Joost nor me can weld, so we went online to look for a substitute. Amazingly, a second hand version was offered online for quite a modest price. So of course, we picked it up :)

see the heat exchange unit on top? 
We connected it to the tub with a simple pool pump in between, and gave it a quick try.

It worked, but especially this early in March, the water lost too much of its temperature to the cold air. So, a bit of insulation was in order!

We had a lot found a of polystyrene foam sheets in the old shed, and thought in to be quite a good, water proof insulation material. So Joost began insulating the tub, and finishing it all with wood.

like that!

Of course, we also needed a place to store the wood for the hot tub ( and the house of course ;)) so we also build a wood storage, mainly from salvaged wood, a few spare roof tiles, and some salvaged pavement slabs.

another days work! ( hmm, will it ever stop?)
We also build a wooden deck to go in front of it, with a foundation of old pavement slabs that we found in the garden ( there were loads of them) for stability and to prevent weeds growing through.

And the almost finished tub!

it only needs a lid!
With the tub as good as complete, a wood shed nearby, and a wooden "landing deck" to get out of the tub, we filled the tub, and gave it a proper try.

Joost is quite happy with the combo of soccer football and hot water... 
and me enjoying a morning swim!
All that was left to do were some final touch-ups, such as building a step to enable going in and out of the hot tub, and depositing some gravel around the tub for drainage.

like that! 
and voila!

I really dig it, and I think it looks quite cool too?
We try not to use any chemical products in the water, so that we can reuse the water for the garden when we need to refreshen the water in the tub. The wood we're using for heating the tub comes from our own garden, and since I'm a firm believer of planting a new tree for every tree you chop down, I kind of hope that I'm not damaging my environmental karma too badly on this one.

 and here are the expenses for the whole project!

Hot tub: 

IBC container:            second hand       40,-
insulation:                   waste material    0,-
wood:                          new                    50,-
pump:                          new                    30,-
installation material:   new                    20,-
heater:                         second hand      150,-

total: 290,-

new, comparable hot tub: approx. 1600,-

saved: 1310,-

I absolutely love it! and big bonus: not only did we improve a previous ugly part of the garden, and create a hot tub for a modest price, we also saved quite a few products that would otherwise have gone to the landfill, such as the reused insulation, pavement slabs, and the old wooden beams. so I very much think of this as a succes!

What do you think of it? I'd love to know!



  1. Amazing! I really, really like it! The tub and surrounding area look perfect.

  2. Loving your short summer series!

  3. Y'all did a fabulous job! I love how you saved other items from the landfill and put them to good use.