TubBlox Kits – Insulated Hot Tub and Pool Walls Made Easy

Tubblox Kits

TubBlox Kits from buildahottub.com are the easy way to create insulated walls for your DIY Hot Tub or Pool. This blog and YouTube Channel focus on helping the DIYer build their own Hot Tubs and Pools.

Easier to lay thank bricks. Better insulation properties than using PIR or Celotex style boards and super-fast to put together means that they are absolutely perfect for the DIYer.

What are TubBlox?

TubBlox are a formwork which is made from expanded polystyrene. TubBlox kits allow the basic hot tub or pool to be constructed from simple blocks, strengthen it with steel reinforcement rebar & then fill them full of concrete. Think of “Lego for adults”!

This method is quick, easy and perfect for the DIYer.

The accessory pieces allow you to create almost any pool or hot tub shape imaginable. The TubBlox Kits have an insulation value which is much greater than traditional construction methods, leading to lower heating costs & savings on energy. In the current climate, it is really important that our DIY Hot Tubs and Pools are fully insulated to keep the running costs down.

Tubblox Kits
Tubblox Kits

Advantages of using TubBlox on your Hot Tub or Pool Build

Constructing TubBlox walls is simple and not labour-intensive. As I have mentioned above, TubBlox are made with incredibly lightweight expanded polystyrene and are hollow in the middle.

The TubBlox are designed with grooves that interlock and allow for easy stacking. The entire construction process is very similar to building with ‘Lego’ blocks.

This building method reduces a significant amount of time compared to a conventional building style. Think about laying blocks. If you are a DIYer like me, you don’t do it very often and it takes forever to get it right. With TubBlox, it’s done in a fraction of the time. They are also much bigger than brick or cement blocks so you need to lay less of them. Again, when you don’t do it that often this is a complete blessing.

Forming up for a concrete pour not only is time consuming but also requires a large amount of timber to do so – timer costs are expensive at present so this can be prohibitive for some. You don’t need the timber for TubBlox – they just glue together – literally! – then fill with concrete!

You can either order in your concrete and have it pumped into the forms (up to 1.75m /5.75’) high or you can mix it yourself. I would recommend buying this in and ordering 4000psi concrete with fibres added for strength. If you must mix and pour it by hand or with a machine, make sure you vibrate it down well.

As you can pour the concrete into the hollow blocks using a concrete pump. You also do not need to stress over stripping and cleaning the forms when you are ready to continue with the project.

While this process can cost slightly more than traditional building techniques using concrete, the amount of labour and time you save using this process will generally make up the difference—particularly compared to the cost of other popular standard alternative insulation techniques.

Uses Less Concrete


You will generally notice TubBlox walls use a waffle-style blueprint as the design uses approximately 10 percent less concrete than if you construct a straight-form option.

Even if you like straight-form blocks when developing a structure, you’ll get better strength with six inches of concrete instead of a traditional eight-inch wall. This strength allows you to potentially save nearly 25 percent of the cost and materials when using this construction method.

 Offers Structural Integrity


Unlike other materials like wood, TubBlox are incredibly durable.

They are resistant to insect infestation, moisture, rot, and other elements that can threaten the structural integrity of your build. Moreover, TubBlox stand up quite well to seismic activity and rough weather conditions such as strong winds.

This durability is due to the rebar that is added into the provided slots of the interlocked TubBlox. The fact the units are glued and rebared together solidifies the structure and keeps it intact even during extreme conditions.

Creates a Healthier Environment


I’ve always warned DIYers about creating warm dry “attractive” places for rodents. TubBlox walls are one of the best and most effective ways of ensuring a rodent-free Tubs and Pools. This is because of the thick barrier of concrete that seals the structure and makes sure no insects or rodents can enter.

This quality is further enhanced because there’s no organic matter in the building material, meaning the insects don’t have anything to feed on.

Allows for Easy Installation of Plumbing and Wiring

Let’s take a minute to dwell on this as this bit is good :). If we build with block, we need to core holes in a 4-8” solid structure with a diamond tipped core drill.

If we use TubBlox, we can punch some holes in a polystyrene form and then fit the plumbing. Doesn’t quite fit? Sand a larger hole with a bit of glass/sand paper. Worst case, use a Stanley Knife to make it a little bigger. How easy is this!

Plumbing and wiring are not an issue with TubBlox. Since the foam is thick enough, Your Pipes and Gunite Bodies can fit straight inside the forms. Simple, tidy, insulated. Tt doesn’t get much better than this.

If you are looking for an easy way to seal things up around the pipes and Gunite bodies, then use a bit of spray foam that you can pick up in any hardware store. No need for

In Conclusion

  • Good insulation, allowing you to save energy
  • Quick construction method, reducing labour by 65%
  • Nice, smooth walls
  • No physical straining
  • Ideal for the “do it yourself” market
  • Hardness PS 40
  • 3,33 pieces/m²
  • 0.14 m³ concrete per m² formworks
  • Thermal rating 0,32W/M²/K
  • Dimensions : 1000 mm x 250 mm x 300 mm

TubBlox Step-by-Step Installation Process

  1. Carry out the Hot Tub or Swimming Pool excavation – essentially dig your big hole!
    hole dug
    hole dug
  2. Prepare your base just as you would for a regular block build.
    Hot Tub Concrete Base
    Hot Tub Concrete Base
  3. Lay the first row of TubBlox on a mortar bed
    TubBlox Kits
    TubBlox Kits
  4. Install the Rebar reinforcing bars
  5. Glue the following courses of Formworks together
  6. Complete the installation of the reinforcing bars
  7. Add your plumbing to the TubBlox during construction.
  8. When you are ready, pour your concrete
  9. Job Done!

Are you Interested in TubBlox Kits?

If you are interested in TubBlox Kits then please do get in touch. I am more than happy to quote your project.

Happy “TubBlox” Hot Tubbin

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

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