Hot tubs are great additions to your yard space and provide a place to relax and unwind, even in the colder months. A deck seems an ideal place to put your hot tub, considering it’s a flat smooth surface.
However, not all decks are created with the weight of a hot tub in mind — it can be hard to tell if your deck will support it.
A deck can support a hot tub if adequately reinforced to handle the weight. Decks built to code can support 50 pounds (22.6 kg) per square foot; however, hot tubs typically weigh more than this. Some modifications may need to be made to your deck to strengthen it.
In this article, I’ll help you determine whether you can place a hot tub on your deck. I’ll cover how to calculate the weight-support ratio and help you find a solution for your hot tub deck setup.
How Much Do Hot Tubs Weigh?
This is a question that features many variables. You need to consider the hot tub itself, the water it can hold, and how many people you can fit in it. All of these factors can add up to a considerable amount of weight.
For the table below I’ve selected three different hot tub sizes. An adult’s average weight is 180 lb (81 kg), so I’ve used this for the calculations.
| Hot tub | Empty weight | Water Weight | Weight of max people | Total weight |
| Bestway SaluSpa St. Lucia AirJet (available on Amazon.com) | 67.9 lb (30.7 kg) | 160 gal (605 l) =1332 lb (604 kg) | Max 3 people =540 lb(245 kg) | 1939.9 lb(879.9 kg) |
| Intex Simple Spa (available on Amazon.com) | 89.8 lb (40.7 kg) | 210 gal (795 l) = 1749 lb (793 kg) | Max 4 people = 720 lb (326.5) kg | 2558.8 lb(1160.6 kg) |
| Essential Edgewater 28 Jet (available on Amazon.com) | 500 lb (226.7 kg) | 300 gal (1135 l) = 2499 lb (1133 kg) | Max 6 people = 1080 lb (490 kg) | 4079 lb(1850.2 kg) |
As you can see, it’s not the hot tub itself or even the people in it that creates a lot of weight. The water adds bulk weight, which can be a lot, especially for the larger hot tubs.
How Much Weight Can a Deck Support?
Modern decks have to be built to the same weight-bearing standards as the floors of your house. This means they have been created to withstand 50 lb (22.6 kg) weight per square foot. Some decks are built to withstand up to 100 lb (43.3 kg) per square, but this is far less common.
Unless you have the deck’s weight capacity stated in your house documents, the only way to truly tell how much weight your deck can withstand is to get a structural engineer to take a look at it.
Of course, you could try and wing it and place your hot tub on the deck and hope for the best. However, I don’t recommend this. You could end up with a hole in your deck and a damaged hot tub!
Can a Deck Support the Weight of a Hot Tub?
If you know which model of hot tub you want and your deck’s load capacity, you can do a simple equation to understand if you can place your hot tub there. First, you need to gather the dimensions of your chosen hot tub to determine the square footage.
For this example, I’ll take the smallest size tub in the above table — The Bestway SaluSpa. This particular model is round, so the width x length measurements are the same: 5.57 x 5.57 ft (1.7 m x 1.7 m). You can use this handy calculator to determine the square footage.
The total square footage for this hot tub is 95.06 ft² (2.8 m²). We have already determined that the total weight of the hot tub at full capacity is 1939.9 lb (879.9 kg).
Now you simply divide the total weight by the total square footage to get the result:
1939.9 lb (879.9 kg) / 95.06 ft² (2.8 m²) = 20.40 lb (9.25 kg)
In this case, you’re in luck! The weight per square foot is less than 50 lb (22.68 kg), so a deck built to code will easily withstand the weight of this hot tub.
What Can You Do if Your Deck Isn’t Strong Enough?
If you’ve got your heart set on a large hot tub, then there are several solutions you can consider. All of these are effective—it all depends on your budget. Of course, the overall look also plays a part.
Reinforcing Your Deck
Having your existing deck reinforced is a popular option. Adding additional support under suitable materials will strengthen it to the desired level. This option does depend on the condition of your deck to begin with.
Old or damaged decks may need to be replaced entirely, so bear this in mind before starting the project. Here’s a great YouTube video from The Spa Guy showing how to reinforce your deck:
Building a Sunken Hot Tub
If your deck is close to the ground, you could consider cutting an area out of your deck and inserting the hot tub to achieve a sunken effect. This is often cheaper than reinforcing your deck and can look really sophisticated.
Adding a Deck Extension
A specially reinforced deck extension is an excellent way to increase your deck space and accommodate your hot tub. You will likely find that the extension will be further from the house, so consider this for the electricity supply.
If you do find you need to run a cable to power your hot tub, here are some useful ways you can do this.
Depending on where you live, you may also require a building permit for an extension. Always check with your local authorities before choosing this option.
Select an Inflatable Hot Tub
As demonstrated in the example above, inflatable hot tubs weigh far less than more traditional hot tub styles. They’re often a lot cheaper too. Modern inflatable hot tubs are pretty robust and have all the features you would get with a rigid tub, such as lighting and fancy jets.
Why Place Your Hot Tub on the Deck?
If you’re wondering why you would want to place your hot tub on the deck first, you should know that this location offers several benefits for a hot tub.
Most hot tubs require electricity to run, so you will need to reach a power supply easily. Situated close to the house will enable you to plug it in without running a new cable anywhere.
The proximity to the house also offers a degree of shelter. Since hot tubs have been designed for use in bad or cold weather, the house’s walls will prevent too much wind chill from reaching you and increase your privacy. Decks typically have some kind of overhead shelter or roof, too, so this will protect you from the rain.
Final Thoughts
Your deck may support the hot tub of your choice. However, if it doesn’t, there are several solutions you can consider.
When installed, deck-based hot tubs create a fabulous ambient space, perfect for sharing romantic evenings or as a place for friends to gather. I always say that hot tubs are great investments and worth the effort.