If you own a deck and you’ve ever considered putting a hot tub on it, you’re not alone. What a great addition a hot tub is to anyone’s backyard area, although it does take a little planning ahead of time. The biggest question many deck owners have is, can I put a hot tub on my deck without it being dangerous to everyone around it?
The answer to that question is “yes,” you can put a hot tub on a deck. That being said, not all decks out there can accommodate a hot tub. As a general rule, if your deck runs two feet off the ground, it can support up to 100 pounds per square foot, which means it can support most hot tubs. But if your deck is more than two feet high, you’ll need to make some alterations first.
The Ins and Outs of Hot Tubs and Decks
The first thing to keep in mind is that many hot tubs can easily weigh more than 5,000 pounds when filled with water and people, so your deck has to be able to accommodate that. When your deck is higher than two feet off the ground, it will need some added support. That includes support posts that are preferably placed in some poured concrete and which are no more than 30 inches apart.
This way, the support posts are evenly spread out and can accommodate your hot tub without any problems. This is without a doubt the easiest way to give your deck and hot tub the support they need so that nothing goes awry.
Here is a very general way to tell if you need the extra support. First of all, if your deck is just above ground level, you likely won’t need any additional support. Second, if it is more than two feet off the ground, it will be easy to fit underneath the deck so that you can add those support beams and posts.
How can you know for sure? If your measurements are close and you’re not sure if the supports are needed, it’s a good idea to have a contractor come by your house and inspect everything so that you’ll know for sure what you need to do to make sure things are safe.
Is Deck strong Enough for a hot tub?
The average hot tub weighs about 500 pounds even when there’s no water in it, and it’s a lot of weight concentrated into a relatively small area on your deck. This is one of the reasons you have to be so picky about making sure your deck can accommodate it. In fact, here are some weights associated with different types of hot tubs, which include both water and people, but note that these are not in-ground hot tubs.
- Small two- to three-person hot tub: 3,000 pounds
- Medium four- to five-person hot tub: 4,420 pounds
- Large six- to eight-person hot tub: 5,500 pounds
As a general rule, the higher your deck is off the ground, the less weight it can accommodate per square foot. If you want to calculate how much hot tub your deck can handle, here is a simple formula you can use: take the empty weight of the hot tub and add 8.34 pounds per gallon of water to this number. So, if your hot tub weighs 500 pounds empty and it holds 500 gallons of water (8.34 x 500 = 4,170), you would add 500 to 4,170 to get 4,670.
Then, add the weight and number of people who will be sitting in the hot tub, calculating each individual at 175 pounds. So if five people will be sitting in your hot tub, add 875 (5 x 175) to 4,670 to get 5,545. If you divide that number by the number of square feet (let’s say, 64), it comes out to a little more than 86 pounds per square foot.
As you can see, this number is below the 100 pounds per square foot usually accommodated by most decks, so you likely won’t need any type of additional support posts and beams for your deck.
Inflatable hot tubs are also a possibility, and you can use the same formula described above when determining if your deck can accommodate a hot tub that is inflatable. In most cases, this will not be a problem because most inflatable hot tubs weigh next to nothing when empty, so you’re automatically starting with a much lower number.
That being said, you may want to add support if your deck is more than two feet off the ground, even when you’re planning to add an inflatable hot tub. After all, it’s very possible you may want to add a better hot tub in future years, and if you do, your deck will be ready for it.
Should This Be a DIY Project?
If you’ve been reading this and have a lot of questions or you’re feeling uneasy about completing this project yourself, just know that for many people, placing a hot tub on their deck is not the perfect DIY project. For many people, letting the experts handle the task makes a lot more sense.
Part of the reason for this is the different types of hot tubs available. Namely, they are hot tubs that sit on top of your deck and hot tubs that are set into your deck (in-ground). The latter, of course, is a little more complicated to plan and install.
If you have an existing deck and you’ll simply be adding the hot tub, the above-ground type is naturally going to be easier to install. Of course, you’ll have to consider the weight of the hot tub using the calculations described earlier. If you’re curious about the requirements for installing a hot tub on your deck, below are some things to consider:
- Make sure your deck has a flat, solid surface for the hot tub. A concrete slab four inches thick works great and can accommodate most hot tubs.
- Make sure you know the exact weight of your hot tub plus the water plus the people. This is not a number you want to guess at!
- If you can, choose your hot tub before making any structural changes to your deck. This way, you’ll know the hot tub will be accommodated.
- Think long and hard about where to put your hot tub. Against the wall of the house? Farther out on the deck? Once it’s set into place, it is difficult to move.
- Make sure you have plenty of room around the tub to enter and exit your hot tub easily and quickly.
- Consider adding some foliage or a pergola around the hot tub so you can have some privacy when you’re relaxing in it.
Conclusion
Having a hot tub placed on your deck can enhance the entire outdoor area, but you have to first be sure that your deck can accommodate the hot tub you wish to buy. Remembering the “100 pounds per square foot” rule is crucial, but it doesn’t stop there. There are other things to consider when you want a hot tub added to your deck.
Fortunately, the things you have to do to determine if your hot tub can be accommodated are simple. Still, if you feel uncomfortable or unsure about any of it, it’s best to hire a professional contractor to do the job for you.
