What Thickness Of a Concrete Pad Is Okay For a Hot Tub? 

So you’re ready to finally take the bold step of getting your hot tub set up, but you don’t know the actual procedures to follow? Not to worry, you will be given all the needed information towards the necessary concrete pad thickness needed to safely harbor a spa.

A hot tub needs a solid, level foundation. It is necessary for the area where the tub is placed to properly support the weight of the tub. If a hot tub placement platform is inadequate, it is likely to shift or cause severe stress to the hot tub’s shell and frame.

Let’s dive right into the things you can use to set up your hot tub.

Your spa’s placement surface is referred to as a “spa pad.” The spa pad can be made of concrete, pressure-treated lumber, synthetic lumber, bricks, or cement patio blocks. A solid concrete pad should be no less than 4 inches thick.

The concrete pad should be at least the same size as the hot tub. If you will be pouring a cement pad, ensure that there’s a slight slope so that the water will not pour beneath the hot tub. A 3/4 “slope in a 10 foot wide cement pad is adequate.

If you intend to use bricks or patio blocks, they should be set on a 3″ base of sand, pea gravel, or crushed stone. It is important you remove sod and roots before putting in the aggregate base, and also remember that the base will be under the tub.

When using bricks, there is no need to slope the pad because water will drain off in-between the blocks.

Can concrete hold a hot tub?

After selecting a suitable hot tub, the next important thing to consider is the foundation. The foundation is the support structure of the hot tub and is very important.

Remember that the weight of a hot tub in a show room and when in use is completely different because when it gets filled with water, adding to the weight of soaking people, it garners almost five times more weight compared to when it’s empty.

This is why more emphasis should be placed on the placement platform for the hot tub.

Now, let’s quickly look at the necessary criteria to follow for a suitable base for your hot tub.

  • A leveled concrete surface: Your concrete face level must be equal and not lopsided; it has to be flat without grade. Even though a slab made of multiple blocks can be used, it is advised to use a single slab because it is more durable.
  • Ensure your slab is in good condition: Your existing concrete slab has to be in good condition. Check for large cracks and uneven surfaces. It should be okay and durable to use.
  • Arrange the hot tub’s foundation placement: The base should be in range of the home breaker panel, which is the hot tub’s power supply. It should also be within reach of a hose or spigot so it can be filled with water.
  • Ensure the slab is large enough to fit your tub dimensions: The slab must be large enough that the hot tub can sit on it properly. Ideally, it should be larger than the hot tub, so there would be space to move around the hot tub or add steps.

How big or thick of a slab do I need for a hot tub?

Without much waste of time, the next big move is to get it set up. It is necessary to know the detailed process of mounting your hot tub, or else you might just be regretting why you didn’t take the time to learn about the process before going on.

Hot tubs, even when empty, are very heavy. Some hot tubs can even weigh up to 2-3 tonnes when they are completely filled with water. Therefore, having a proper ground base is important towards setting up your hot tub.

The most popular or common ground base for hot tubs is a concrete foundation. It allows for smooth installation and keeps it strong and sturdy. Your hot tub base can either be made to fit the size of your hot tub or even more than it to create space around the tub or add steps to it.

The concrete base needs to be a minimum of 4 inches thick so it is able to withstand the weight of the hot tub. It is also advised that the rubble should be placed on the foundation for maximum support or to reinforce the concrete base with rebar.

How much does it cost to pour a concrete slab for a hot tub?

According to a recent survey, the national average cost for pouring a concrete slab for a hot tub is ,925.

Concrete slabs are important for the hot tub‘s in-ground base.

How long after pouring concrete can you put a hot tub on it?

Although some hot tub owners say the concrete would be able to cure in one week, it is generally recommended that you allow the concrete slab to rest for two weeks before going on to install and fill up your hot tub with water.

How long should fresh concrete be kept wet?

Curing your concrete is one of the most important steps towards setting the base of your hot tub. A single mistake and you can leave everything in ruins. In this article, you’ll be given valid information on curing your concrete.

In the first week, after your concrete is poured, it is necessary to maintain the proper temperature and dampness for appropriate curing.

One of the problems that arises from not curing your hot tub is horizontal surfaces. An uncured slab will likely develop a pattern of fine cracks called crazing. This can make the surface weak once it’s in use, which can result in a dusting surface that has little resistance to abrasion.

What is the best base to put a hot tub on?

After buying a hot tub, the next real step is to set it up, and that is where the base comes in.

Do take note that hot tubs are very heavy and it is paramount to make sure that the support structure, which is the base, is strong enough to carry them appropriately. In this quick guide, you’ll become acquainted with what the best base for your hot tub is and how you can set it up nicely.

Let’s quickly look at the basic options available to you.

  • Concrete base: This is one of the most common tub bases for spa owners. In fact, most hot tub experts say it is the best base option. It offers strong support for the base and also keeps the area around the base clean and tidy. Concrete is not too expensive and it is easy to lay. A concrete pad that is at least 1 cm thick is highly recommended for a good base. Also, the concrete should be sloped at 1.5 cm per 3.5 cm. This is to ensure water runs off the pad and prevent pooling.
  • Patio: Most patios are reinforced and are likely to take the weight of a hot tub placement. One of the benefits of using an existing area is area of cost savings. It is also worth ensuring the stones are level and the drainage is okay to avoid pooling under the hot tub.
  • Decking: Decking is another popular option when it comes to hot tub base, the design makes it look great and it feels better underfoot when getting into and out of the hot tub. Unfortunately, like everything that has a good side, the bad side of decking is that it does not last long. Its durability is highly flawed. Another major drawback of the base is that a deck attached to a house can increase noise and vibration from the spa pump.

Having known all the bases available to you, we recommend that you go with a concrete base because it is cheaper and very affordable.

How flat does a concrete base need to be for a hot tub?

Framing a concrete base is important towards giving your hot tub’s support structure a proper balance.

The concrete base needs to be a minimum of 4 inches thick so that it is able to withstand the pressure and weight of the hot tub.

Here are easy steps towards building a concrete base.

The first step to take is to build a frame made from 2-by-4 lumber. Now, you can either pour the concrete directly onto the dirt, or lay at least 4 inches of gravel down first. Then pour the concrete into the frame and leave it to cure.

Allow the frame to cure for at least two weeks before going on to install your hot tub.

Also, take note that not allowing your concrete base to cure properly can spoil the process. Improper curing leads to reduced compressive strength development and increased drying shrinkage.

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