How to Determine if a Deck Can Support a Hot Tub?

By Calvin | Last Updated: June 1, 2021 | Guides / Space Planning

If you just got a hot tub, and you have a deck. You must be wondering if the deck can support the hot tub weight. After all, hot tubs weigh a lot. So, how to determine if a deck can support a hot tub?

If your deck was installed less than 2 feet from the ground level, then chances are the deck can support your hot tub. If your deck was installed higher than 2 feet from the ground level, then you would need to modify the deck.

A deck installed below 2 feet from the ground level can support about 100 pounds (45.3 kilograms) per square foot of weight You don’t need to be discouraged. My deck was installed about 4 feet from the ground and it still bears the weight of my 6-person hot tub. I just had to modify it.

Can you place your hot tub in a deck? Yes, you can. But, you need to reinforce the deck so it can handle the hot tub weight.

Can a Hot Tub Be Placed on a Deck?

Absolutely, but it needs to be reinforced to do so. It is advised to have a professional come and check it out to verify that you can place a hot tub on it. With the proper support, your deck can bear the weight of your hot tub at full capacity of water and bathers without any stress. You just have to choose the method of installment that you want.

Before we move on, here is a quick heads up for you. Placing your hot tub on your deck is not a project you want to take on yourself. While there are parts of the project you can do, the bulk of the calculation and placement should be left to a professional.

I probably know more about hot tubs than you do and I still consulted help for mine. A poorly installed hot tub on a deck can lead to serious injuries to the bathers and damages to the house. So, get help.

Methods of Hot Tub Installment for Decks

When it comes to placing hot tubs on decks, there are two methods of installment. Both methods require a strong and leveled surface.

There two ways you can put your hot tub on your deck. You can put it on the deck (literally), or inside the deck. If you put it inside the deck you will have to create a hole and fill the hole with concrete and then place the hot tub.

Related Read: Can I Put My Hot Tub on Ground?

What Should I Consider Before Placing My Hot Tub on My Deck?

Before placing a hot tub on the deck, you should consider a few factors such as:

Can I Put My Inflatable Hot Tub on My Deck?

Provided the deck is in good condition which means it has no splinters, breaks, or rots that can puncture or damage the tub eventually, yes you can.

Inflatable hot tubs at full capacity weigh about 3500 pounds. Divide that number by the square feet of the hot tub which is about 38 sq. ft., you will get 92 pounds per square feet in weight.

That is very much suitable for a deck installed 2 ft. above ground level. If the deck was installed higher than that, you might need to install a few extra beams. Regardless, you should be fine with an inflatable hot tub on a deck in good condition.

The weight of the inflatable hot tub makes it possible for them to be placed on just about any deck without serious concern.

What you need to consider is the condition of the deck. While most inflatable hot tubs are engineered to be puncture-resistant, you shouldn’t test the level of resistance by placing it on a damaged deck full of splinters and broken wood.

Related Read: Do Inflatable Hot Tubs Have Seats?

How to Determine if a Deck Can Support a Hot Tub?

Remember when your teacher said something like, “pay attention in math class, you will need the knowledge in the future”? Well, your teacher wasn’t lying.

To know how much weight your deck can support, you will need to do a bit of calculation. There are different ways to go about this, but let’s consider an easy one.

To calculate how much weight your deck can support, you need the following in numbers:

For this explanation, we’ll be using the figures of a 6-person hot tub.

Note that even with this, there are still different models of a 6-person hot tub out there. The figures below are mere representations of just one type of the 6-person hot tub. The figures of your 6-person hot tub or any other hot tub you have could be different. You can just substitute the figures below for yours.

Related Read: Why Should You Use Cold Water in a Hot Tub?

How Do I Make My Deck Strong Enough for a Hot Tub?

There is a golden statement with decks and hot tubs. “The higher the deck is from the ground, the lower the weight it can supportIn other words, a lower deck can support heavier weight than a higher deck.

First, you need to know if your deck can hold a hot tub. If it doesn't, then there are some stuff that you can do to make that happen. So, if you are asking yourself how can I modify my deck to hold a hot tub then it's easy. You just have to reinforce the base or install extra support beams

If your deck is higher than 2 feet from the ground, then you should consider modifying the deck. So, how do you go about modifying your deck to hold a hot tub?

There are usually two ways to modify a deck when it comes to hot tub installation. Both methods depend largely on the method of installation you want.

Install Extra Support Beams

If you aim to place your hot tub directly on the floor of your deck, then your installer will advise you to Install extra support beams so the deck can support the weight of the tub.

For this method, thick wooden posts or beams are installed about 30 inches apart from one another. The number of posts required will depend on the posts previously installed, the size of the tub, and the weight of the hot tub.

Usually, about 7-9 extra posts should be enough. The posts will go into the ground and be placed underneath the area of your deck where you want to place the tub.

Install a Concrete Slab Below

If you aim to place your hot tub inside the deck, then you would need to install a concrete slab below your deck.

This method is common among people that have decks that are already high, usually 4 feet and above. The height of the deck from the ground makes it possible for your installer to go underneath the deck easily.

For this method, you might be required to create a space in your deck for the hot tub to sit. This means saying goodbye to a part of that fancy woodwork. Not to worry, something even fancier is coming in its place.

When space is created, the ground is dug and then filled with crushed stone, gravel, and sand to serve as the foundation. Then a concrete slab is installed on it.

The concrete slab is what your hot tub will sit on. The slab is usually 4-6 inches thick and that is more than enough strength to support your hot tub.

After the hot tub is set in place, the spaces between the hot tub and the deck will be covered with hardwood to make the space look even and neat. The bonus point of this method is that your deck is doing nothing. The concrete slab is doing all the work while the deck just houses the hot tub.

Related Read: Can I Put an Inflatable Hot Tub on My Deck?

Can a Trex Deck Hold a Hot Tub?

The term “Trex” sounds like those tough German or Russian names you hear in movies. Like “Victor”, “Vladimir” or “Rusev”. That’s just me joking around, let’s get serious.

A well-installed Trex deck can support the weight of a hot tub provided it is strong enough. Trex is also called “composite decking.” The Trex deck is not stronger than normal lumber or wood, but it is more resistant and durable. A Trex deck will not rot, will not splinter, and will not crack for a long time. Trex is usually advised for outdoor wooden structures like decks because of its high resistance to harsh conditions.

In terms of strength, a Trex deck matches the normal wooden deck so don’t misinterpret durability for strength. If you want to install your hot tub on a Trex deck, you can but you should take into consideration what we discussed above.

As long as the Trex deck is strong enough, it can support the weight of a hot tub.

There you have it. If there is anything else about hot tubs you aren’t sure about, you can let me know below in the comment section and I’ll answer your questions as soon as possible. Have a nice day.

Hi, I'm Calvin Hall, the owner of Hot Tub Wiki. I worked at a local Spa Service for a few years before creating this website. I have owned several hot tubs and fixed a thousand of them. So, I know a thing or two about hot tubs.