How to Build the ULTIMATE DIY Wooden Hot Tub

Building your own DIY Wooden Hot Tub is arguably one of the great DIY projects you can undertake. It requires skill. It requires attention to detail. The end result however, is just fantastic! There is nothing more satisfying that sitting in your own home made wooden hot tub.

If you are a regular reader of my blog, you will know that I have made my own DIY Hot tub. Not out of wood, but in fact bricks and concrete. You can read about it here. What I wanted to do in this post was compile everything that I have read from around the internet and combine that with my knowledge.

I would then put my own twist on the design adding my DIY Hot Tub plumbing knowledge and come up with a guide for building the ultimate wooden DIY Hot Tub.

DIY Wooden Hot Tub Design Considerations

The considerations for building your own wooden DIY Hot tub are really no different from a regular Hot Tub. You need to think about where you are going to locate the wooden tub. What is the base going to look like? Can the base take the weight of the tub?

Remember, water is heavy when you fill a large vessel with it – we’re probably talking over a ton for sure.

How many people is this going to seat? How am I going to heat this up to temperate? This point is kind of key as the bigger the body of water, the more power is needed to bring it up to and maintain the temperature.

The worst thing that you could do is design something that is too large to ever get up to temperature. At one point, I thought that this was going to be the case on my own build. Thankfully, I had the guidance of “pool man John” who reigned in my size expectations. That advice is advice I pass on to my own clients now.

Yes, you can have a big hot tub but you need to make sure you plan and design correctly so that you can actually heat it up!

Don’t Fancy Building a Wood Hot Tub from Scratch? No Problem! We can Provide it in Kit Form.

Use our configuration tool below to put together that dream wooden Hot Tub package. Choose the size of the tub, how it is powered, whether you would like stairs or jets. We’ll cost out the package and even show you what your Hot Tub will look like.

What Wood Should I use for my DIY Hot Tub?

Cedar

Cedar is a beautiful timber and is certainly my favourite. I actually made my own decking with Cedar Timber. The most difficult part of a DIY cedar hot tub is finding an affordable source of clear cedar lumber. You don’t want any cedar with knots for your hot tub as these can blow out and cause a major leakage! That said, clear cedar (#1 grade) is expensive and most lumber yards don’t stock it, so it’s somewhat rare to come by.

You are going to need to fund a lumber yard that probably stock the Grade 2 Cedar. You also are going to need to find one that will let you sort the timber yourself. These are quite hard to come by for safety reasons so its probably a case of ringing around.

Larch, Beech, Oak, Pine

All of these are cheaper options for building your own DIY Wooden Hot Tub. The timber is much cheaper than the Cedar so if you are trying to do this on a budget, then we would highly suggest that you use one of the above.

How do I Make a Cylindrical Shaped Hot Tub?

In order to make a cylindrical Tub with your timber, you are going to need to use bead and cove joinery to do it. Using a router, you are going to need to make the edges look like the image below. This is not something a first time wood worker can probably have a go at successfully. Especially if you have shelled out on the expensive Cedar timber, it would make for really expensive fire wood if you get it wrong and don’t know what you are doing.

You are then going to need to strap it together to your cylindrical base. To hold the tub together, use a 3/16″ vinyl-coated cable which shouldn’t cause any harm to the wood. You will need two clamp sets for each cable to give the ends a nice finish. You then need to attach the two ends with a stainless steel turn buckle

You tub is going to swell as the timber absorbs water and it is also going to leak the first time you fill it. This is totally normal and it may take a few days for it to swell enough to seal all of the leaks. What you also have to consider is that if you leave it unfilled and in the sun, the timber is going to shrink. Again, this is normal.

Do I need a Cylindrical Hot Tub?

Absolutely not. Building the ultimate wooden hot tub doesn’t mean that it has to be cylindrical. Conversely, it is actually easier to make a cube or square shaped Hot Tub. Yes, there is still an amount of skill that is required to building any wooden hot tub, but arguably it is much easier to make a square tub.

This tub below is being built (at the time I am writing this post) by one of my customers Brandon in the USA. He actually set out to have a Stock Tank hot tub but couldn’t find the supply of the tank he wanted, so decided to make it out of wood.

Just as a side note here, there are also different ways of waterproofing your wooden Hot Tub.

How do you Waterproof a Wooden Hot Tub?

In the cylindrical option that we have explained above, the design of that tub is that it is “self-waterproofing”. The joints you make are designed so that when the tub absorbs water, the wood swells, the joints become tighter and as such, so tight that it is waterproof.

The option that Brandon is going to use above, is a pool liner inside of his wooden shell. There is no reason at all that why this option is not viable. It actually works really well and is much easier to do.

How will I heat my DIY Wooden Hot Tub?

DIY Wood Fired Hot Tub

You can’t argue with the fact that the wood burning stove-powered Hot Tubs just look cool. Never mind the fact that they are not costing you a fortune to run. The lure of a hot tub that doesn’t hurt you in the wallet is certainly something that some aspire to having.

There are two different types of wood burning hot tub heaters. There are the heaters which sit in the tub with you and the fire is basically on the other side of a metal wall. Usually, there is a cover over it to stop you touching it. These heaters do on the flip side take up some space in your tub that could be used for another person for  example.

The other type of wood burning Hot Tub heaters are external. If I were going to build one of these, this would be the style that I would go for. Built the fire on the outside, and let the heat flow into the tub.

Lastly, there are the “cooking pot” style that have a hot tub sitting above a fire. I just don’t like the idea of this and it looks to me more like a witch’s pot cooking a human rather than a hot tub. Not for me. But each to their own of course.

Propane of Natural Gas

Propane or Natural Gas heaters are nothing new to the swimming pool world. The are more suited to a swimming pool because of the sheer power that they can generate. To give you an idea, my Hot Tub heater is a 3KW heater. In the USA, I design systems that run on 5KW heaters.

There is no shortage of Propane heaters that will generate a whopping 32KW of heat. That is a serious heater!

I guess the argument is the same with electric, you are going to need a supply to your tub in order for this to work. This really depends on a lot of things but running gas pipe isn’t something you can do yourself as a DIYer, you do have to get someone in (or risk voiding you home insurance policy!)

Depending on the placement of your tub, this could be somewhat problematic. That said, if you are going to need a “big boy” heater as you are basically building something the size of a swimming pool, then this might be an option for you.

Electric

Call me predictable, but this is the option I would choose. Yes, it costs more to run, but there is reliability. There is predicability. There is just less hassle. The idea that I would have to go out and build a fire, get it going, then wait for the tub to heat up before I can use it just to me seems like too much hard work.

Use the control panel. Set the temperature and let technology do the rest.

For me, this is what I am going to us in the design of the ultimate DIY wooden Hot Tub.

Do I need jets in my wooden Hot Tub?

The “traditional” wood burning or wood fired DIY Hot Tubs generally don’t have jets. In my mind, this kind of design is more like a bath than a Hot Tub. Therefore, when I was coming to design the Ultimate DIY Wooden Hot Tub, it just had to have jets. In my mind, it was going to be exactly the same as if I was designing with a Stock Tank Hot Tub or a Concrete tub.

The pluming, although slightly different parts are needed, does remain pretty constant. My ultimate wooden hot tub was going to have jets. It was going to have a heater, a filter and a pump. It was going to be a proper (again, of course, this is subjective, but proper in my mind) Hot Tub.

To answer the question, yes, you need jets in a wooden Hot Tub.

Do I need a Filter?

There are a lot of tubs out there that you can find by Googling on the internet which are as I describe above, simply wooden baths. If you dont put a filter and a pump in, it is a bath. Again, this is in my humble opinion.

If you are filtering the water, adding chemicals to it, not changing it every time you need to use it, then this is a proper hot tub. A bath is just that. It is a one time use and then you empty it.

For something that is arguably much larger than a domestic bath, it doesn’t make sense to have it only as a single use tub. Firstly, it is a waste of water and secondly, you are going to be heating up what is quite a large body of water just to throw it away afterwards. Doesn’t make sense.

So, in answer to the question, yes, you do need a filter if you are building a wooden hot tub.

What is the Ultimate DIY Wooden Hot Tub?

In my mind, the Ultimate DIY Wooden Hot Tub comprises of a cedar tub, combined with the “mod cons” of Jets, a Filter, a 2 speed pump, an electric heater and a blower.

It will look something like the below image.

We can Supply you a DIY Wooden Hot Tub Kit – Everything you Need for your Own Custom DIY Wood Hot Tub

Use our configuration tool below to put together that dream wooden Hot Tub package. Choose the size of the tub, how it is powered, whether you would like stairs or jets. We’ll cost out the package and even show you what your Hot Tub will look like.

How do I Assemble the DIY Wooden Hot Tub Kit?

All of our Wooden Hot Tub Kits come with assembly instructions and can be put together over a weekend. You normally only require common house hold tools such as screw driver, an electric drill, 1/8″ wood drill bit, rubber mallet, 2 adjustable wrenches, saw or utility knife.

This is definitely a two person job so you will need to ask a friend!

Assembling the Kit is a six step process. Step 1 you can do in advance of your kit arriving.

Step 1 – Preparing the Ground / Foundations

Having a solid, flat base that can take the weight of the tub is essential. You can prepare a concrete slab, lay some flags, fill a gravel base, there are lots of options. The general rule is it needs to be flat and be able to take at least a tonne in weight. Water is heavy remember!

Step 2 – Position the base

The base that we ship with the kit is pre-made. This is to ensure that you get off to a great start with your DIY Hot Tub. Position the base where you are going to have your final tub. Remember, the Tub itself is quite heavy once you have assembled all the parts so you don’t want to be moving it once it is assembled.

Step 3 – Install the Stave

The staves have all been milled and routed so they are ready to be tapped into place with a wooden mallet. The angles are perfectly crafted so that the staves will slot into place and create that water-tight seal needed for a DIY Wooden Hot Tub. Using only 100% Clear Western Red Cedar! No Knots! Our tubs stand 48″ high with 47″staves (sides), this allows for nearly 43″ of interior depth, giving the ultimate soak experience!

Once the Staves are in place, you will then add the straps. We use only 304L grade stainless steel straps and screws to eliminate any rust or oxidization.

Step 4 – Install the Seats

Adding the seats is just a case of screwing the pre-cut parts into place. It really could not be any easier. Bi-level hexagon seat structure, allows for different heights and soaking levels, great for kids! The upper seat makes entry into the tub easier.

Step 5 – Install the Plumbing

All of the holes are pre-cut for the jets and full plumbing diagrams are provided. The plumbing is screwed and cemented into place. It is very much like following a set of instructions from our favourite kids block maker – lego! Adjustable Industrial Cedar Jets designed specifically for wooden hot tubs ensures durability, and include 1″ air valve for maximum adjustable jet pressure. The dual air controls allow for individual adjustment of jet pressure.

Step 6 – Complete the build, fill with water and Enjoy!

There is nothing more satisfying than climbing into the DIY Wooden Hot Tub that you built yourself! They simply have so much more character than the plastic shell tubs on the market. With the wood burning options, you can also be totally off the grid if you wish.

Specifications

	Small	Medium	Large	X-Large
Max Users	4	6	8	10
# of Seats	3	6	6	6
Diameter	56″	65″	74″	84″
Height of Ground	48″	48″	48″	48″
# of Jets Standard	4	4	4	4
Max # Jets	6	8	10	10
Gallons (IMP)	294	400	523	687
Gallons (US)	352	480	628	825
Liters	1334	1819	2378	3124
Pump size HP	1	1	1	1
Heater	5.5kw/Chofu	5.5kw/ Chofu	5.5kw/Gas	5.5kw/Gas
ElectRequired Service Required	2P-40A GFD	2P-40A GFD	2P-40A GFD	2P-40A GFD
Weight (Including Tub)	3300lbs	4400lbs	5750lbs	7700lbs
Chofu Wood APRX Heat Up Time	3-4	5	6	9
Electric APRX Heat Up Time (Hours)	9	11	15	19
Natural Gas/Propane APRX Heat Up Time (hours)	2	3	4	5

Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi

 

Hi, Andi here. I own Buildahottub.com and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Today, I've helped over 1000 DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi