Everyone loves the idea of putting a hot tub on a deck and walking right out from the house to a private jacuzzi. Yet it’s not always as simple as just setting one down. Decks look strong, but they are usually not built to withstand the weight of a hot tub, plus all the water and occupants. So properly preparing your deck is vital to avoid a catastrophe.
A hot tub weighs 2,500 lb to 6,000 lb, with inflatables being lighter than acrylic. When deciding to put a hot tub on a deck, you want to look at the deck’s age, access, hot tub size, and cost. DIY reinforcement is doable but talk to a contractor before making any changes.
Putting your hot tub on the deck can be an excellent idea and add to its entertainment value and overall usage. Still, you want to consider if it’s doable and feasible before just going ahead and installing it on your deck. Thankfully, half the work is done if you already have a hot tub; you need to figure out if your deck can handle the weight.
Can You Put a Hot Tub on Top of a Deck?
The short answer is yes, but the long answer is maybe. Putting your hot tub on your deck is entirely possible, but there are many things to consider.
A deck, for instance, is designed to hold 50 lb per square foot, which is not even close enough to support a hot tub plus all that water needs.
Suppose you’re planning to build your deck before installing a hot tub. In that case, it is a good idea to calculate the load-bearing capacity first and adjust for joist spacing, joist overhang, footing size, and soil type, as they will all factor into how much weight your deck can safely hold.
Certain types of hot tubs are better suited to be installed on a deck than others. For instance, an inflatable hot tub has the least amount of weight due to the materials it is made up of.
Filled with water and with four adults inside, an inflatable hot tub will weigh roughly 2500 lb. In contrast, an acrylic hot tub will weigh over 5000 lb. So not only is it important to think about the deck, but also the type of hot tub you want.
How Much Weight Does a Deck Need to Hold for a Hot Tub?
Determining the weight of a hot tub so it can sit on a deck can require some thought. It’s not a simple one size fits all matter, but there are some basic measurements we can use to help determine the load-bearing capacity needed.
For a small 2 to 3-person hot tub, you are looking at 3,000 lb, including water and people. A 4 to 5-person hot tub is 4,420 lb, and a large 6 to 8-person hot tub is 5,500 lb.
Inflatable hot tubs weigh less, with a small 2 to 3-person hot tub only being 2,700 lb and a 4 to 6-seater weighing 3,700 pounds.
Other Considerations When Installing a Hot Tub on Your Deck
Age of the Deck
Over time, wood gets weathered and decayed, so if you plan to put a hot tub on an already established deck, it is important to consider how old the deck is and the condition of the wood. There is also the fact that construction standards might have differed when the deck was built as opposed to today.
Everything that goes into building a deck can determine the structural integrity, from lag screws to joist hangers. Therefore, it is crucial to ensure you know how old the deck materials are and how well they were constructed.
Most decks have stairs and access that lead out to a yard, which is a good setup for a simple deck. However, with a hot tub, there is the risk of someone wandering onto the deck and potentially falling in or getting hurt. This is the same risk for pets and children.
A good idea to think about when considering putting a hot tub on a deck is how it can be blocked off so no unwanted guests inadvertently hurt themselves.
Another thing to consider is a water source. You want to make sure a hose or another form of water access is available to your deck, or it will be a lot of trips with a bucket.
Hot Tub Size
Consider the size of the deck before putting a hot tub on it. You don’t want to take up the entire deck with just a hot tub and leave no room for sitting or entertaining.
Take into account other activities you do on the deck or would like to do alongside owning a hot tub, and decide whether or not a hot tub will fit comfortably in the space without compromising other tasks.
Many people are surprised by how much extra it costs to reinforce a deck so it’s strong enough to hold a hot tub. Hiring a contractor can add another $5,000 to the project budget, while even just replacing some boards and a railing can be an extra $500. Always consider the extra overhead cost before attempting to put a hot tub on a deck.
How Do You Strengthen a Deck for a Hot Tub?
Strengthening a deck can be easy or tricky, and it is best to consult a professional contractor before making any adjustments and placing the hot tub on the deck.
The last thing you want to do is end up with the hot tub going through the deck because of a miscalculation. However, to reinforce your deck yourself, you can follow these few simple steps.
Keep in mind that if you are in a location that results in frost heaving, you will need to perform additional steps involving cementing the posts.
What You’ll Need
- Four pressure-treated 4x4x8’s.
- Four pile-on blocks that hold a 4×4.
- Four galvanized twisted straps to hold the 4×4 to the deck joists.
- 4-8 2” wide flat straps to hold the legs to the cross beams.
- Hang two of the 4x4x8’s about 1’ in from the width of the hot tub across the joists, touching as many joists as possible.
- 1’ in from the other length of the hot tub, place the pile on blocks as flat as possible.
- Cut 4×4’s to the length needed to touch the already hung 4×4 and the blocks.
- Tap the legs into place with a 3-5lb hammer and install the 2” wide straps, connecting the 4x4s and the legs on either one or both sides to keep the legs from moving.