Does a Hot Tub Have to Sit on Concrete? (In Detail)

If you are planning to install a hot tub in your bathroom or backyard, knowing some basic facts about its installation is essential. One of the biggest misconceptions is that hot tubs can only be set on a concrete base. But the reality is totally different. So, does a hot tub have to sit on concrete exclusively?

Concrete is not the only suitable surface for installing hot tubs. Almost any strong base that is level and smooth enough can be used. The surface, however, cannot get damp or distorted by the moisture. Some of the perfect bases for a hot tub include wooden decks, spa pads, gravel beds, paver stones, cinder blocks, and so on.

I’ve talked about some of the basic surfaces that are suitable for hot tubs, and now I'd like to provide some valuable insights into this topic. Reading the complete article you’ll learn more on your options when deciding a base for your hot tub and understand your choices. So, let’s begin. 

Is Concrete Slab Mandatory for Hot Tub Installation?

There is absolutely no doubt that concrete slabs are the best base option for a hot tub. However, it definitely isn’t the only option. Different bases would work best for different circumstances.

While choosing the base, most people consider using a concrete slab since it works fine on almost every surface. But it is not the most efficient option as making a concrete slab is pretty expensive.

For example, many people out there want to install a hot tub in their backyard. Feeling the natural beauty while soaking into hot water takes the bathing experience to another level. Now, are you willing to make a concrete slab in your beautiful backyard? In this sort of scenario, there are better choices.

So in short, no. Using a concrete slab for setting the hot tub is not the best option for every situation either. Later on, I will explain how you can choose the perfect base depending on the surrounding of the hot tub.

What Hot Tub Bases Can you Use Besides Concrete?

It cannot be denied that setting up a hot tub and maintaining it is not very cheap. The electricity cost alone can take a big bite from your wallet if you use it regularly. Although the price of the hot tub has significantly decreased, the whole process still takes a good amount of cash to complete.

On top of that, concrete slabs are by far the most expensive base option for hot tubs of any size. So, for cutting the overall cost, using an alternate base option would be smart. Some of the bases I will talk about below might even work better than a concrete slab depending on your situation.

Paver Base

Paver stones are a good option for the hot tub’s base. They are strong, unbendable and moisture does not affect them at all. In fact, in my backyard, the hot tub is set on a paver slab and it is working flawlessly. Paver slabs are an even better option than concrete ones if you are planning to install the hot tub on a grass surface.

But before starting the installation process, there are a few things that you need to keep in mind. First of all, all the paver stones should be of the same size. Stones with ridges will make the hot tub shaky and water might leak. You will find pre-constructed paver slabs on the market, buy the flat one.

Ever heard of the term efflorescence? It basically means loss of water or salt from a hard surface due to exposure to a very dry environment. In normal words, the structure loses its overall strength with time. Another great advantage of using a paver surface is, they have a very low absorption rate. And due to that fact, they are pretty much immune to efflorescence.

While installing the hot tub, you will have to hide the electrical lines under the surface. Imagine the hassle you will have to face if you use a concrete slab and some sort of electrical malfunction occurs. If you, however, use a paver slab, the maintenance would become simple. Even if some malfunction occurs, all you have to do is remove the paver slab, repair the electrical lines, then put the slab back.

Pros

• Very strong.
• Have a lower absorption rate.
• Easy maintenance.

Cons

• Not very cost-efficient.

Wooden Deck

For those who are tight on budget, a wooden deck can be a perfect base for hot tubs of any size. But you will have to keep in mind that wood is very fragile, so the deck must be strong and thick enough to support the weight of you, the water, and the tub. A weaker base will break and might lead to a disastrous accident.

Although, if the deck is 2 feet up off the ground, having additional support is not a necessity, but still recommended. But if you want to place the tub even higher, multiple support posts are required and all of them should be set at a distance of 30 inches or less. Making a wooden base is sensitive work, so if you are not an expert, don’t do it yourself.

One of the biggest advantages of owning a wooden deck is, they are very cheap compared to paver surface or cinder blocks. Also, if you want to place the tub high up from the ground, then a wooden deck is the most obvious choice. They are very customizable and the overall maintenance cost is much less than other available options.

If you are determined to use a wooden deck, then be very cautious. First of all, most of them are fragile, so you will have to use the best wood you can find. Using supporting posts is a must. As we all know, woods get heavily affected by water and moisture, so the longevity of the wooden base is poor and you might have to replace the supporting posts once in two years.

Pros

• Very cheap compared to the other bases.
• Highly customizable.
• Looks great.
• The maintenance cost is high.

Cons

• Fragile.
• Easily gets affected by moisture.
• Can be used only on the grass surface.

Cinder Blocks

Cinder blocks are another fine option for a hot tub base as they are relatively strong and can carry a significant amount of weight. Especially, if you don’t have budget issues, they might be the perfect option for you. All the blocks that will be used as a base should be smooth and of the same size.

Now, placing the cinder block directly on the grass surface wouldn’t be ideal. You should dig the ground to 4-6 inches, then level the soil with a shovel so that the cinder blocks do not move. Then, pour the hole using a sand bed. You don’t want a watery mess after every bath you take, and a sand bed is perfect for sinking. Finally, place the cinder slab on the sand bed and you are good to go.

One of the biggest advantages of using cinder blocks is, they are much stronger than a wooden base or a concrete slab. The density of the cinder block is higher than most other materials, so you can install heavier hot tubs on them. In particular, if you are planning to install a hot tub for your whole family, then using a cinder block base would be good.

Keep in mind that there are some undeniable disadvantages of using cinder blocks as a hot tub base. First of all, finding the perfectly smooth blocks is a challenge itself, and if they are slightly uneven, the tub might crack. They don’t look as good as paver base, in spite of costing almost the same, and installation costs are much higher.

Pros

• Very strong.
• Supports heavier tubs.
• Quite cheap.

Cons

• Expensive.
• Doesn’t look good.

How to Choose the Perfect Base For Your Hot Tub?

I have already talked about various base options for a hot tub. They all have different advantages and disadvantages. But how can you choose the perfect surface for your hot tub? It actually depends on your budget and the surroundings of the tub. Keep in mind that all of the mentioned options would work, so if you are tight on budget, just go for the cheaper one.

But, if budget is not an issue for you, then choose the base depending on where you would like to set the tub. For instance, paver slabs are by far the best option for installing a hot tub on a grass surface. Cinder blocks can also be used, but I personally recommend using paver stones as they are stronger and look much more premium.

Now, let's say you want to install the tub six feet above the ground. In such cases, using paver slap or cinder blocks would be very expensive and concrete won’t work whatsoever. So, using a wooden deck would be ideal. Keep in mind that they are very fragile and using the right type of wood is absolutely essential.

Finally, if you want to set a hot tub in your bathroom, just use a concrete slab. As you might have guessed, setting a paver slab or cinder block in your bathroom is possible, but very impractical.

As you can see, there are various options available when it comes to the base of the hot tub. In this article, I have extensively talked about whether or not does a hot tub have to sit on concrete exclusively. Hopefully, after reading the whole article, you will be able to find the base option that suits you best. Until next time, farewell.