Hot tubs are a fantastic way to increase both the utility and appeal of your outdoor space. They’re a great way to pass the time, no matter the season. But can your wooden deck support the weight of a fully-filled hot tub? The answer to that question depends on a few different factors. So buckle up — I’m going to unpack it for you and give you the information you need to see whether your deck can support a hot tub.
Hot Tub Weight
First, we need to figure out exactly how much the hot tub will weigh. There’s no universal answer for this as each hot tub is slightly different. However, you can use the following formula to determine how much your fully-filled hot tub will weigh.
Empty Weight of the Hot Tub + (Hot Tub Capacity in Gallons * 8.34)
Why 8.34? That’s the approximate weight of a gallon of water!
You might be wondering how much the empty weight of your hot tub is. You can find this information in the manual or on your specific manufacturers website. To give you a general idea, I’ve put together this handy table.
|Model||Empty Weight||Water Capacity||Filled Weight|
|American Spas 2-Person Hot Tub||600 lbs||130 gallons||~1,684 lbs|
|Laguna 3-4 Person Hot Tub||425 lbs||230 gallons||~2,343 lbs|
|AQUA 6-Person Hot Tub||800 lbs||425 gallons||~4,344 lbs|
|American Spas 7-Person Hot Tub||800 lbs||425 gallons||~4,344 lbs|
As you can see, filled hot tub weights can range anywhere from 1,500 to 4,500 lbs. This is large range! Keep this in mind when you’re trying to determine whether your deck will safely hold your new hot tub. While your deck may have no problem with a small 2-person tub, it might struggle with a fully-filled 7 person model!
Deck Load Capacity
This brings us to the next part of the puzzle. How much weight can your deck safely handle? I have to again state that many factors are involved when calculating this number. Few decks are in optimal, brand-new condition and you should take that into account. If you’re wondering, here are some factors that may impact the total weight capacity of your deck:
- Age of the deck.
- Type of wood used.
- Level of rot / mildew / mold.
- Space between the joists.
- The size of the beams / support posts / joists.
- How secure the foundation is.
Each of the above items can drastically impact the total capacity of your outdoor deck. I can’t guess how much it will effect the capacity. I can only give you the load capacity of a well-built, newly constructed deck. From that, you can make the determination about the condition of yours and adjust accordingly.
So, what’s the load capacity of a standard deck? Generally, we’re talking about 50 pounds per square foot. This means that if you had a 100 square foot deck (10′ x 10′), you’d be able to hold 5,000 pounds above it (assuming the weight was evenly distributed). For comparison, a 7-person hot tub is roughly 7′ x 7′.
Can Your Deck Support a Hot Tub?
So, will you be able to support a hot tub on your wooden deck? Probably! However, you might have trouble if your deck is older or in poor condition. Even still, there are steps you can take to reinforce your structure to ensure it’s sturdy.
For instance, you might add additional struts around the location of the hot tub. An extra beam or support post wouldn’t hurt either.
Try It Out
If you’re still unsure, you should still consider trying it out. It’s very unlikely that you’ll sit the hot tub down and cause the deck to collapse. The deck will generally start to bend/sag before it will completely break. You can simply monitor the situation and move the hot tub if you notice any problems. Keep a level handy to check for sagging and be sure to look underneath the crawlspace for bulges.
Have any more tips? Share them in the comments and help out your fellow patio enthusiasts!