How To Determine If A Deck Can Support A Hot Tub


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Over recent years the popularity of hot tubs has increased greatly, with many homeowners having the luxury of owning their own. But wait, although all is straightforward when placing it onto a concrete pad, what if you want the hot tub on your deck. Do you know how to determine if a deck can support a hot tub? 

Because a hot tub weighs a lot when full, careful planning needs to be done for its placement. So, before you go rushing out to invest in your desired hot tub. Be sure that your existing deck will safely hold the weight of the hot tub. 

Please note, placing a hot tub on an existing deck should be done with extreme caution. Personally, if you are unsure I recommend that you use a qualified professional such as a qualified contractor or structural engineer. This way you will find out exactly how much weight your deck will take per square foot.

Remember, you will be endangering the lives of your family and friends should a deck collapse happen. 

So, keep reading this article to help you determine if your deck can safely support a hot tub. 

What Are The Benefits Of Putting A Hot Tub On The Deck

Generally, installing a hot tub on your deck can be an excellent way to enhance the aesthetic appeal of your backyard, as well as provide a place to unwind and rejuvenate. But, aside from these, it can also be beneficial in the following ways:

  • Increases the value of your home: Adding a hot tub on your deck can make your home more valuable. If you’re planning to sell your property in the future, the hot tub can be an attractive feature for your potential home buyers. As such, they’ll be willing to pay more money for the sale price. 
  • Provides you with a place to entertain your friends: If you love hanging out with friends, a hot tub on your deck can be a great place to stay. Given the natural ambiance and style, you and your friends can enjoy a bottle of wine while spending time in the hot tub. 

Gives you an opportunity to heal and relax: Aside from the relaxing effects, soaking in the hot tub can also have healing effects. For example, if you’re suffering from sore muscles or arthritis, a soak in the hot tub may help you heal and relax.

Can A Deck Support A Hot Tub? Load Bearing Capacity

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With modern hot tubs costing less to run and models becoming more affordable, more people are wondering if they can put a hot tub on wood deck boards.

Because of the obvious weight difference between permanent and inflatable hot tubs, the deck load capacity and structural support needed to take the total weight of a hot tub will vary. Therefore, the answer to can you put a hot tub on a deck will also vary.

Although most decks built to good deck building standards will support 100 lbs per square foot, the weight of a hot tub is not evenly distributed over the whole deck but is concentrated in a small area. Making how many pounds per square foot the existing beams are designed to take all the more important.

It’s worth noting here, that a standard deck lower than two feet, with support posts at least every six feet, will support more weight to square footage than decking that is raised above the 2 feet height.

To be extra sure, you may ask a qualified professional who’s familiar with the different types of hot tubs, their sizes, and their capacities. Doing so would be a great idea because they’ll be able to help you find the appropriate product that fits your deck load capacity. 

How Much Does A Hot Tub Weigh (Inflatable & Permanent)

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Once again, there is going to be a difference in weight between an inflatable hot tub and a permanent hot tub. For most hot tubs, you will be able to find both the dry weight and the total weight (filled) listed in your owner’s manual. 

For example, the weight when empty of an inflatable hot tub is minimal. Whereas, a large permanent spa can weigh as much as 800 lbs before any water even touches it. Put water and people into the equation and you are talking 2,700 lbs for a small 2/3 person inflatable. Compared to 3,000 lbs for a small 2/3 person permanent tub. 

Here’s a handy chart showing an estimate of each of those and how much they weigh (roughly) empty, full, and at capacity with occupants:

Type of Hot Tub Empty  Water Only People & Water 
Small 2-3 Person Hot Tubs 600 lbs 2,575 lbs 3,000 lbs
Medium 4-5 Person Hot Tubs 750 lbs 3,700 lbs 4,420 lbs
Large 6-8 Person Hot Tubs 800 lbs 4,300 lbs 5,500 lbs
Inflatable Hot Tubs (2-3 people) n/a 2,200 lbs 2,700 lbs
Inflatable Hot Tubs (4-6 people) n/a 2,700 lbs 3,700 lbs

How To Determine If A Deck Can Support A Hot Tub (Calculations)

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As I mentioned earlier, I would advise that you use a professional for advice on how much weight can a deck hold. Especially those of you that have a raised deck of over 2 feet. 

However, there are some calculations you can do for yourself to work out the weight of your new hot tub into pounds per square foot. 

Step 1. 

Find out what the weight of your empty tub is, (this will either be in the owner’s manual or on the manufacturers’ website). 

For the purposes of this example, I am using the Miami Lay-A-Spa, 68 lbs. 

Step 2. 

While you are at it, find out how many gallons of water your hot tub holds. A gallon of water weighs 8.34 lbs

The Miami holds 192 gallons, the sum would be 192 x 8.34 = 1,600.

Step 3. 

For the purpose of this calculation, the average weight for each person is taken to be 185 lbs. (When calculating this always allow for the most number of people likely to be in the tub at any one time). 

In my example, I am taking 2 people as the maximum 370 lbs. 

Step 4. 

Now work out the square footage of your tub. (For this, I cheat and use google). 

The Miami is 6ft round therefore 28.27 square feet. 

Step 5

Now for the final sum. 

Weight of empty tub + total weight of water + total weight of people divided by the square footage.

68 + 1,6oo + 370 / 28.27 = 72 lbs per square foot.

Can You Modify Your Deck To Support A Hot Tub?

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Although decks can be modified to take hot tubs, never attempt to do this as a DIY project. Unless of course, you are fully qualified how to reinforce a deck for a hot tub. If the deck should collapse under the weight lives could be lost. 

Choosing The Right Place For Your Hot Tub

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Yes, weight does play an important part when choosing the right place for your hot tub. But, there are other factors to be considered to achieve the best hot tub experience. Here are just a few pointers for you. 

  • Make sure you have a level surface.
  • Avoid placing under trees that are likely to shed leaves and twigs etc.
  • Think about how close you want it to the house, the shorter the walk is in cold weather the better.
  • Will you be in full sun or shade during the summer months?
  • Will you have easy access to the tub. Make use of outdoor furniture for towels and gowns.
  • You do need to change the water reasonably regularly. Do you have a drain close by?
  • Electrical supply. Have you got a lead long enough to reach the electrical outlet?

Final Thoughts

Remember, placing hot tubs onto decking that is not structurally strong enough is extremely dangerous and can put lives at risk. Please, if you have any doubts whatsoever, employ qualified professionals to check it out for you. 

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