Hot Tub On Deck

Hot Tub On Deck

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Our outside deck is an ideal spot for entertaining friends and family, dining al fresco, or just relaxing and reading a book. However, you want to take things a step further. You’ve decided to install a hot tub on your terrace.

Before continuing, it’s vital to realize that installing a hot tub on the deck is generally not a do-it-yourself effort. Rather than that, we advocate a strategy that combines meticulous preparation with the assistance of skilled specialists. Otherwise the hot tub, sometimes bearing a weight of more than a thousand pounds, could be collapsing

regarding the installation of a hot tub on deck, we have two there are two types: those that sit above your deck and those that are built into it. The embedded hot tub is an alternative for individuals who do not want to spoil their view or who just do not want to get into an elevated (called also “above-ground”) hot tub on a deck.

Elevated hot tubs are simpler to accommodate into an existing deck, making them a superior option for some. However, you must consider the weight capacity of your deck.

A hot tub on a deck is perfectly feasible, and your deck may already be outfitted to accommodate one. A deck with a minimum load capacity of 112 lbs per sq. ft can sustain practically any style of hot tub on the deck. Nevertheless, many decks are only built to sustain an average of 49 lbs per sq. ft this will not support certain hot tubs, necessitating the modification of the supports under the deck.

The homeowner intending to construct a new deck might be required to start by calculating the load-bearing capacity of the envisaged future deck. This is dependent on a variety of elements, including joist spacing, joist overhang, footing size, and soil type. Then calculate the total weight of your intended hot tub on deck with all its gross weight. 

There are several structural concerns to make when designing your backyard if you want to include a hot tub on the deck. We recommend that you have a licensed specialist assess your decking initiative. The contractor will inspect the structure for structural soundness and ensure that it is capable of supporting the hot tub.

To precisely calculate the joists and beams for such a huge weight, homeowners must contact a structural engineer or will utilize beam-design charts, algorithms, or software programs designed specifically for decking and terrace building. If the deck is elevated, municipal authorities often need an engineering design.

If you already have a deck built that, however,  cannot support the additional weight of the prospective hot tub it is not a big issue. it is perfectly feasible to adjust the supports for your deck to accommodate it.

We will discuss how to arrange the design and the structure for a hot tub on a new deck and how to alter an existing deck to support a hot tub in depth below in this article.

Hot Tub Weight

We have to know the gross weight of the hot tub to calculate if the deck can resist it.

Furthermore, we have to consider the lateral forces produced by the shifting of the water flow laterally when the users move inside. This lateral pressure has to be calculated by the structural engineer when determining if the current or planned deck can support the hot tub we plan to acquire.

The Michael Phelps Legend Series LSX 900 is, for example, one of the largest hot tubs. This 8-person hot tub can be loaded with 500 gallons and has seventy-two jets. It has a gross weight of about 6,900 lbs at its full utilization.

Hot tubs with a smaller footprint, such as the Twilight Series TS 6.2, weigh about 3,739 lbs. The TS 6.2 is a five-person hot tub. 

Condition Of The Deck

If you are contemplating the installation of a hot tub on a deck, it is critical to examine the deck’s condition.

An older deck’s timber may have deteriorated and should be replaced.

Additionally, the building code standards may vary from those in use today.

Everything from lag screws to joist hangers to the placement of the major beams may have an effect on the deck’s structural stability.

Available Footprint

If the installation of the tub takes up too much space and leaves little room for chairs or other accessories, this may not be the ideal solution. Consider if you are willing to sacrifice room for a sofa, tables, and other patio furniture in order to accommodate the hot tub on deck.

Availability Of Water For Filling And Draining

A deck in a second floor might be a problem for filling and draining the hot tub on deck. You should have a spigot or a garden hose that you can utilize.

It is recomended that the water is changed once per month. Thus, the problem of filling and draining the spa will appear relatively frequently.

Hot Tub On Deck Cost

A contractor could offer you a design for strengthening the deck in order to support the gross weight of a hot tub. But the determining element may not be the structural engineer´s approval. It might be the costs.

The reinforcement of a deck to support an eight-person hot tub might cost over $5,270. Even a basic railing and changing planks and sistering deck joists may cost $600 on average.

The project costs should not have to ruin your expectations. You may want to consider installing the hot tub on a concrete pad or similar flat, level area that can hold the required weight.

Recessed hot tub in deck

A recessed hot tub on the deck can be an option that might however require a reinforcement and a fully recessed installation can facilitate the access to the spa for older users.

The service provider will perform a cutout of a determined area of the deck to accomodate the hot tub required by the homeowner.

Furthermore, this recessed installation requires a reinforcement with footings in order to handle the structural load of the planned hot tub with consideration of its gross weight at full utilization.

The homeowner must consider if the requirement is of a fully recessed hot tub on deck or a partially recessed installation wherein the users can seat at its edges. This has to be decided before planning the reinforcement of the deck.

Hot Tub On Deck Support

The optimum kind of support for a hot tub on the deck is a concrete slab at least four inches deep under the decking to withstand the vertical loads and the lateral forces provoked by the shift of water mass.

With an elevated deck, additional support joists and beams might well be required underneath it to increase the deck’s load capacity. Typically, a deck elevated less than a few feet can support an average of 96 lb sq. ft, which is sufficient for the majority of hot tubs.

A structural engineer is often required prior to installing a hot tub on any kind of decking. They will inspect your deck to ensure that it is robust enough to support the required hot tub will make recommendations for any necessary adjustments.

Apart from structural support, it is critical to ensure that your deck is entirely leveled prior to installing a hot tub. You do not want to have all of the water weight concentrated on one side of the hot tub, as this might cause damage to the inner layer due to the lateral forces triggered by the shift of the water mass.

A hot tub on deck encompasses a huge weight distributed in only a small surface of a few square feet. Therefore, it is possible that the homeowner is obliged to reinforce the structure and provide support.

A deck raising two or more feet above the ground level, which typically might have supporting posts with a six-foot span is not enough to support the structural vertical force of the gross weight of the hot tub.

If the deck raises less than that or it is just an elevated platform, you might not require reinforcement.

If the deck raises above the ground much more, a person can crawl below and install the support beams and posts required, as when it happens when sistering joists in a crawlspace.

Obviously, in the case of inflatable hot tubs, we should rarely worry as the weight of the hot tub is much lower.

To establish the amount of structural support required for your hot tub, you must first compute the JGW (Jacuzzi Gross Weight). This measurement may be accomplished by multiplying the empty weight of the hot tub by its water capacity (1 US gallon is roughly  8.34 lbs) multiplied by the total weight of the occupancy at its maximum hot tub capacity according to the manufacturer specifications.

For the latter, we will take the standard US weight for a person that for 2022 was 187 lb.

We will multiply this weight for the maximum number of users according to the manufacturer specifications and then perform an algebraic sum of the net weight of the hot tub + water capacity + maximum occupancy weight for US users.

A practical example will clarify everything. Let´s see

Let´s take the most common hot tub in the US, which is the four-person capacity hot tub.

So we have a four-person, 44 sq ft hot tub (671 lb) that requires 281 US gallons (unit of volume) of water which is 2344 lbs (unit of weight).

The gross weight is approximately the algebraic sum of

  • 748 lb: weight of the occupants
  • 671 lb: net weight of the hot tub (just look at the manufacturer specs to know)
  • 2344 lbs: weight of the 281 US gallons (unit of volume) required at full utilization

So we have a gross weight of 3763 lb.

The gross weight requires to be divided by the surface of the required hot tub on deck in order to establish the determination of its structural load per sq ft.

3763 lb divided by the 44 sq ft is 85.53 lb per sq ft. This is what the deck needs to support.

The structural engineer will put these measurements on paper and this is what you will need to apply.

So as a conclusion, a solid, leveled surface, such as a concrete slab, is perfect for your hot tub’s placement. For homeowners who have chosen to construct a new deck on which to install their hot tub, a slab must be prepared and poured in addition to the concrete deck footings. A slab of around 4″ will be adequate for the majority of hot tubs.

Can You Put A Hot Tub On A Deck?

Can you put a hot tub on a deck?

You can put a hot tub on a deck that can withstand a structural load of at least 98 psf. As construction standards for decks have lower requirements, homeowners must reinforce the structure adding support beneath the deck to enable the installation of a hot tub in a safe manner.

If you are building a new deck, the first step is to figure out how much weight your deck can handle.

There are a slew of variables to consider, including the distance between joists, the overhang of joists, the size of the footing, and the kind of soil.

Determine after that, the total weight of the hot tub, including persons, when it is fully occupied.

If you already have a deck, it is not a big deal since adding a new hot tub to your deck will not be an issue thanks to deck support modifications. Adding a hot tub to an existing deck or building a new one from scratch is covered in the sections below.

Types Of Hot Tubs for Decks

Portable Hot Tubs

Portable hot tubs are actually huge and cannot be transported easily by a single person.

These hot tubs are called “portable” because the hot tub package contains all the devices required to operate it and they can be easily uninstalled and installed elsewhere.

Nevertheless, they are lighter than standard hot tubs and make our calculations much easier.

Inflatable Hot Tub On Deck

Can I put an inflatable hot tub on my deck?

Yes, is the short answer.

Because inflatable hot tubs weigh almost nothing when empty, they are quite a bit lighter than a permanent hot tub.

we see that even a large inflatable hot tub will likely be about 2,000 lbs lighter when full of water and people than the equivalent regular hot tub.

If we apply the formula I mentioned above for a large inflatable hot tub, we have:

  • Weight of the spa (empty) = virtually nothing
  • # of gallons of water (290) x 8.34 lbs (how much a gallon weighs) = 2,418.60
  • Add those 2 numbers = 2,418.60
  • # people (6) x 175 = 1,050
  • Add that number to the previous total = 3,468.60
  • Divide that by the number of square feet (38.37) = 90.40

So, again, for decks that are basically ground level, most likely you’ll be just fine with no added support for a large inflatable hot tub.

For a deck that is 2 or more feet above the ground, even though it’s not nearly as heavy as a full-sized, non-inflatable, I would still recommend adding the extra support; who knows? You might eventually want to add a full-sized hot tub later on!


Inflatable hot tubs are just that – they come in a (large) box and need to be inflated. Often they come with proprietary pumps, such as the Coleman inflatable line of hot tubs.

These hot tubs are anywhere from 60 – 100 pounds when deflated, making them a truly “portable” hot tub. Typically these are made from a multi-ply vinyl – a.k.a PVC. Imagine a giant, really, really sturdy inner tube – that’s an inflatable hot tub.

Inflatable hot tubs, of course, don’t come with a pump, filtration, or any other equipment within. There is a standalone unit that comes with inflatable hot tubs that connects to the tub, functioning as the pump, filter – if there is one – and other plumbing required for the inflatable hot tub to function.

Since the weight of these tubs is far less than the other tubs, you can put one on a deck. For instance, a four-person inflatable hot tub holds around 220 gallons of water. That’s around 1700 pounds without people. Add 4 medium-sized people, and you are looking at nearly 2500 pounds.

If you have 2500 pounds of hot tub and person on your deck, and your hot tub’s diameter is close to 7’, then you are looking at roughly 75 pounds per square foot on your deck. Most decks must be built to withstand at least 50 pounds per square foot. So there is a 25 pound per square foot discrepancy.

However, with some modifications to your deck frame and foundation, your deck can safely hold a fully inflated and occupied inflatable hot tub.


An acrylic hot tub has an inner shell made out of acrylic, with an outer shell made of another type of material that covers the insides of the hot tub. One of the most common types of “portable” hot tubs, these are popular because they come in copious amounts of different styles since the outside shell can be customized for a wide variety of looks.

The acrylic shells are often made with either fiberglass layers or ABS layers beneath for added reinforcement. Top of the line models has thin sheets of steel in areas of the tub that need extra-reinforcement.

Acrylic hot tubs can be heavy. It is not unusual for an empty hot tub to weigh close to 1000 pounds. A 7 or 8 person hot tub filled and occupied can reach upwards of 6000 pounds – that is no easy weight for a deck to hold.

Can a deck hold an acrylic hot tub? Absolutely. However, special considerations must be taken when framing and installing footings. The deck structure will need to be reinforced significantly before you plop a larger acrylic behemoth on your deck.


Also known as polyethylene, these types of hot tubs are all one unit of molded plastic. There is a mold filled with plastic powder, then the mold is turned as the exterior of the mold is heated. The powder melts and is evenly distributed throughout the mold.

In many aspects, a molded – or “roto-molded” – hot tub is similar to a giant plastic bin with jets. It is far more lightweight than an acrylic hot tub – anywhere from just under 200 pounds to over 400.

The portability of these tubs, combined with their toughness, makes a good option to place on a deck. Since these hot tubs are a fairly simple design, they are also cheap. While not quite as cheap as inflatable tubs, they can still check in at around $2000. Higher priced models are bigger and offer more features, but still don’t compare to the hefty price tag of an acrylic.

A roto-molded tub runs on a regular household, 15-volt outlet. That means they are not huge drains on your electrical bill. The downside is that it takes a long time to heat them because the pump and heater are designed to work on the said outlet. Also, they lose heat quickly due to their all-plastic body.

Do You Need a Permit for a Hot Tub?

Sometimes. A permit is fast becoming a requirement for many municipalities across North America. Check with your local building services department to find out if it is required where you live.

For instance, you do not need a permit for a hot tub if you live in Houston. In Tampa, you don’t need a permit if the hot tub is not hooked up to plumbing or hard-wired to your electrical system. However, you do need one if you live in Toronto or Los Angeles then you do need a permit for a hot tub.

Remember, you do not need to erect a fence around your hot tub if you have a cover that locks. This will ensure your hot tub passes code.

A deck with a railing over 6 ft. from the ground, with locking gates at all entry points, will also suffice for a hot tub on a deck without a locking cover.

Lastly, some jurisdictions only require permits for hot tubs that have an 8 foot or longer stretch of open water. Smaller hot tubs in those places do not require permits.

Hot Tub On Deck Weight

Luckily, determining the weight of your hot tub empty, filled, and fully occupied by a group of people is fairly simple. Since we know that water weighs about 8.3 pounds per gallon, we can accurately calculate hot tub loads.

Therefore, we’ll simply be taking the manufacturer’s specs for the dry weight of hot tubs and the average weight of the North American adult – 178 pounds. Combine those two factors with our weight of water per gallon, and we can easily discern if your deck can handle any type of hot tub.

Below we’ll take a look at the weights of several different types of the hot tub. All weights are in pounds (lb.)

TypeDry Weight (Empty)Weight with Water onlyGross Hot Tub Weight Rating
2-Person Acrylic60016852035
5-Person Molded44524103765
7-Person Acylic80043405586
8-Person Acrylic58945005924
Inflatable, 2-4 Person7015402250
Inflatable, 6-Person5622403308

How Much Weight Can a Deck Hold

A deck’s load-bearing capacity can get confusing, so we’ll try to make this as clear as possible.

The construction of a deck is made easier with charts that outline the maximum lengths of your joists, posts, and beams. They also include variations for different joist spacing, lumber type, and footing type.

If you build your deck to code, abiding by all the structural requirements as outlined in your local building code, then you’ve only built your deck to support 50 pounds per square foot. Why? This is the default – and most common – standard for deck building, and it won’t be enough to support most hot tubs.

Since deck load charts only include loads of 50 pounds per square foot, decks will need reinforcement to hold a larger hot tub. Luckily, there are deck load calculators available online that can help you adjust your joist span and sizes to accommodate a heavier load.

Unfortunately, these are only helpful for new deck builds. Plus, you also have to know the maximum weight of your new hot tub.

Remember, a standard deck built to code is only rated for 50 pounds per square foot – that includes a 10 pound/square foot dead load (the weight of the actual structure) and a 40 pound/square foot live load (anything on the deck surface, such as people or a hot tub).

When you put a 4000-pound hot tub on a deck, your live load doubles, at least. Therefore 50 pounds per square foot will not work. Also, keep in mind that the weight of a hot tub is concentrated in one area, so it is likely that you’ll need even more reinforcement in that one area because the weight is not spread out and can skew your support calculations.

How To Determine If A Deck Can Support A Hot Tub

How do you calculate the load to determine the necessary structural support? Add up the tub’s dry weight plus the water capacity (1 gallon of H2O equals roughly 8.3 lbs.) plus the number of recommended occupants multiplied by an average weight per person.

Decks built ground level up to 2 feet off the ground can support up to 100 lbs per square foot; sufficient for most hot tubs. But decks 2 feet or higher will need added support. The added support posts should be no more than 30″ apart & ideally placed in poured concrete.

The best way to explain if an existing deck can hold a hot tub or not is to compare an existing 10 x 10 deck built to code without a hot tub on it. Standard deck beam charts show acceptable spans with various types of lumber and plys, that will support a 50 pound per square foot load.

As I’ve already explained, that calculation will not work for a hot tub. Remember, it doesn’t matter how high off the ground your deck is or not. If the deck is off the ground by even an inch, the same thinking applies – you’ll need to reinforce your deck.

To determine the load-bearing capacity of your deck, you’ll want to know the tributary area of your deck posts. That’s how much weight each post can hold. Let’s say your 10×10 deck is supported by 3 posts plus a beam at one end, and a ledger board on the other with joists running perpendicular to your house.

To find the tributary load of a post, multiply half the length of the joist – including any distance the joist cantilevers over the beam – by half the distance of the beam on both sides of the post. If our beam is at the end of the deck, with no cantilever, then half the distance of the joist is 5’ and half the beam length on either side adds up to 5’, too.

So, if we multiply the two together, the tributary area of the middle post on our 10×10 deck beam is 25 square feet. Now, multiply that by 50 pounds/square foot and you get 1,250 pounds. If you were to place a 7-person hot tub in that tributary area, with a total weight exceeding 4,000 pounds, then you could risk structural failure and injury – or worse.

If you look at this tributary load chart, it will show that if you keep your tributary area low – meaning you include more beams and/or posts – then the maximum length of a post of any size will be quite high – 14 feet. This means that the most effective way to reinforce your deck is to add more posts and beams.


Dimensional Lumber Deck Beam Spans Supporting a Single Span of Joists with or without Overhangs:


 Joist Spans
 Species Size Beam 6′ 8′ 10′ 12′ 14′ 16′ 18′
Southern Pine  2-2×6 6′-8″5′-8″5′-1″4′-7″4′-3″4′-0″3′-9″
 2-2×8 8′-6″7′-4″6′-6″5′-11″5′-6″5′-1″4′-9″
 2-2×1211′-11″10′-4″ 9′-2″8′-4″7′-9″7′-3″6′-9″
 3-2×6 7′-11″7′-2″6′-5″5′-10″5′-5″5′-0″4′-9″
 3-2X12 15′-0″13′-0″11′-7″10′-6″ 9′-9″9′-1″8′-7″
Douglas Fir-Larch,Hem-Fir,Spruce-Pine-Fir,Redwood,Cedars,Ponderosa Pine,Red Pine  3X6 OR 2-2X6 5′-2″4′-5″3′-11″3′-7″3′-3″2′-10″2′-6″
 3X8 OR 2-2X8 6′-7″5′-8″5′-1″4′-7″4′-3″3′-10″3′-5″
 3X10 OR 2-2X10 8′-1″7′-0″6′-3″5′-8″5′-3″4′-10″4′-5″
 3X12 OR 2-2X12 9′-5″8′-2″7′-3″6′-7″6′-1″5′-8″ 5′-4″
 4X6 6′-2″5′-3″4′-8″4-3″3′-11″3′-8″3′-5″
 4X8 8′-2″7′-0″6′-3″5′-8″5′-3″4′-11″4′-7″
 4X109′-8″ 8′-4″7′-5″6′-9″6′-3″5′-10″ 5′-5″
 4X12 11′-2″9′-8″8′-7″7′-10″7′-3″6′-9″6′-4″
 3-2X6 7′-1″6′-5″5′-9″5′-3″4′-10″4′-6″4′-3″
 3-2X8 9′-5″8′-3″7′-4″6′-8″6′-2″5′-9″5′-5″
 3-2X10 11′-9″10′-2″9′-1″8′-3″7′-7″7′-1″6′-8″
 3-2X12 13′-8″11′-10″10′-6″9′-7″8′-10″8′-3″7′-10″

Assumes 40 psf live load, 10 psf dead load, L/360 simple span beam deflection limit, cantilever length L/180 deflection limit, No. 2 Stress grade, and wet service conditions.

As I’ve already explained, that calculation will not work for a hot tub. Remember, it doesn’t matter how high off the ground your deck is or not. If the deck is off the ground by even an inch, the same thinking applies – you’ll need to reinforce your deck.

To determine the load-bearing capacity of your deck, you’ll want to know the tributary area of your deck posts. That’s how much weight each post can hold. Let’s say your 10×10 deck is supported by 3 posts plus a beam at one end, and a ledger board on the other with joists running perpendicular to your house.

To find the tributary load of a post, multiply half the length of the joist – including any distance the joist cantilevers over the beam – by half the distance of the beam on both sides of the post. If our beam is at the end of the deck, with no cantilever, then half the distance of the joist is 5’ and half the beam length on either side adds up to 5’, too.

So, if we multiply the two together, the tributary area of the middle post on our 10×10 deck beam is 25 square feet. Now, multiply that by 50 pounds/square foot and you get 1,250 pounds. If you were to place a 7-person hot tub in that tributary area, with a total weight exceeding 4,000 pounds, then you could risk structural failure and injury – or worse.

If you look at this tributary load chart, it will show that if you keep your tributary area low – meaning you include more beams and/or posts – then the maximum length of a post of any size will be quite high – 14 feet. This means that the most effective way to reinforce your deck is to add more posts and beams.

For single-level wood-framed decks with beams sized in accordance with Table R507.5, deck post size shall be in accordance with Table R507.4.

4 × 46-9c
4 × 68
6 × 614
8 × 814

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.

  1. Measured to the underside of the beam.
  2. Based on 40 psf live load.
  3. The maximum permitted height is 8 feet for one-ply and two-ply beams. The maximum permitted height for three-ply beams on post cap is 6 feet 9 inches.

And then there is snow load to consider. However, if you’ve accounted for the total weight of your hot tub and reinforced your deck accordingly, then snow shouldn’t be an issue simply because a deck built to code will take into account snow load based on typical winter conditions for that specific geographic area.

Lastly, remember that the height of your deck isn’t as important as how far apart your posts are spaced and the size of your posts. If you have a deck close to the ground, you could still encounter issues if you don’t have enough posts.

Deck Load Calculator For A Hot Tub

if your deck is ground level or under 2′ off the ground, you should be just fine with no additional support.

  • Weight of Empty Hot Tub = Varies depending on the chosen model
  • 1 Gallon of Water = 8.34 lbs
  • Average Weight of Person = 185 lbs
  • Square Feet of Hot Tub = Varies depending on the chosen model

Using the values above, use the following formula to calculate the weight a hot tub will put on your deck:

[Weight of Hot Tub + (Number of Gallons of Water x 8.34 lbs) + (Number of People Spa Can Seat x 185 lbs)] / # of Square Feet = Pounds Per Square Foot

Here’s a link to a hot tub we’ll use as an example in the formula. It seats four people and holds 195 gallons of water. 

[375 lbs + (195 x 8.34 lbs) + (4 x 185 lbs)] / 29.17 = 93.97 lbs Per Square Foot

In general, most decks can withstand 100 lbs per square foot. So if a hot tub like the one in the example is under that weight, the average deck should be able to support it. Of course, this isn’t something you’ll want to guesstimate. It is always wise to contact a professional to get an accurate estimate of what your deck can safely handle.

How To Reinforce A Deck For A Hot Tub

Modifying an existing deck will require more posts, and perhaps another beam. But how do you accomplish this without tearing up your deck and starting fresh? There are several ways you can go about altering your deck without starting over – here are a few methods below:

Add A Beam

Adding a beam to fit between two existing beams – or a beam and a ledger board – is possible, and potentially easier than simply adding a post to an existing beam.

To add a beam, you’ll need to remove deck boards. Once removed, you’ll have to operate between your joists. If they are 16” apart or more, this is possible.

If you are installing patio stones with deck blocks on top, then your job is fairly easy. You can also install screw piles, working around the joists.

What you cannot do is dig a footing beneath an existing deck unless your deck is high enough off the ground for you to fit under. If you can, then digging is probably your best option to support a post.

Add a Post

Adding a post beneath an existing beam is tricky, simply because if your deck is within 5’ of the ground, then getting underneath the beam and digging isn’t an option. At best, digging in those circumstances is extraordinarily uncomfortable. Therefore, you need to find another way to support the beam.

One way is to level the earth beneath the existing beam for a patio slab, deck block, and adjustable post holder or post.

This does not give the same amount of added capacity that a new beam would, but adding several to a beam can reduce the tributary load tremendously and increase the deck’s load bearing capacity at the same time.


The added support posts are 30″ apart from one another. Posts ideally would be placed in poured concrete and run at least 1 foot below the frost line.

Hot Tub Deck Design

Keep in mind that when designing a new deck with a hot tub on top, you’ll only need to add extra reinforcement to the area right below the hot tub. So instead of overbuilding the entire deck to account for the added weight of the hot tub, you build a deck to standard code and reinforce the area beneath the hot tub.

On the other hand, it may be easier to add another beam to your new deck, even if it spans beyond the footprint of the hot tub, just for peace of mind and consistency in design.

Whichever method you choose, you’ll need to consult with the calculators linked above from the AWC, as well as the span tables, to see how far apart your joists need to be, how many posts you’ll need, and how to size your deck beam.

Overall, the best way to hold a hot tub is a concrete pad. A pad with a deck built around the hot tub will let you rest easy at night because this is by far the best way to support a hot tub, particularly a larger one that gets experience loads beyond 5,000 pounds.

Materials For A Deck With A Hot Tub

Pressure-treated wood is an inexpensive option to use for decking. This kind of wood is prone to warping and only has a life expectancy of around 15 years. It can be recycled after use.

Western red cedar is a recommended option when it comes to hot tub decking. It is softer, which reduces the chance of getting any splinters. It is also insect and fungus resistant. This wood will last on average 30 years. If you want a certain color you will have to stain it every 2-3 years. Otherwise, it will turn a natural gray.

Ipe wood is an exceptionally long-lasting wood with a life expectancy of around 40-50 years. It comes from Brazil and has very few knots to contend with. It’s also low maintenance, only needing upkeep in the form of oiling it once or twice a year.

Hot Tub On Composite Decking

Can a Trex deck hold a hot tub?

Yes, is the short answer.

Trex is simply a brand name for what’s called composite decking. That’s a fancy way of basically saying fake wood or plastic decking.

Now, I’m not knocking it, but since most of us don’t speak contractor-ease, I wanted to be clear about what Trex is as most of us have seen it.

Composite decking is roughly 20% more expensive than traditional pressure-treated lumber, so it doesn’t fit into every budget.

Now Trex isn’t stronger than traditional wood, so to calculate whether or not you need additional support under your deck to hold the weight of a hot tub, follow my calculations above.

The advantage of Trex comes from the fact that it, like all brands of composite decking, won’t splinter, crack, or rot. Further, it also is highly resistant to mold, mildew, and moisture in general.

While a traditional wood deck might last up to 15 years, Trex and most brands of composite wood will likely last 25 years or more and most come with a 25-year warranty.


If you are building a deck with Trex composite lumber, then you’ll have to keep in mind that a standard 12’ Trex deck board is almost double the weight of a standard treated deck board. Be sure to reference a Trex-specific beam span chart when planning a deck and hot tub using Trex lumber.

Cedar framing will have considerably less weight-bearing capacity compared to SYP structural lumber and somewhat less than SPF – reference this load bearing chart. This will have to be considered when adding a hot tub to a deck made completely from cedar lumber.

Using a composite material made from wood fibers and other products is a low maintenance route to take for your deck. While it only needs to be washed a maximum of 3 times a year, it also tends to take on damage easily. This kind of material can’t be recycled or sanded. Newer composites are much better for staying cooler if you have a full sun deck.

Placement For A Hot Tub On Deck

A flat, level surface such as a concrete slab is the ideal location for a hot tub. If you’re building a new deck, the slab should be formed and poured at the same time as your concrete footings. A 3-1/2 to 4 inch slab is usually sufficient, experts say; however, larger tubs may require something more substantial.

Distance from the House

Ensure there is a door nearby (or a well-lit path) for quick dashes indoors on chilly evenings.

Placing your hot tub against the wall of the house gives you some extra privacy and blocks wind so that you can be more comfortable on chilly nights. And the closer the tub is to a door, the faster you’ll be able to dash inside and warm up! 

If cold weather isn’t a concern and you’d like to place your spa farther out on your deck, make sure you have slip-resistant decking or mats leading from it to the house. Even with mats, it’s also a good idea to keep your wood deck properly sanded so no one ends up with a splinter in their foot when they’re getting out of the tub. 

Accessibility And Safety

You’ll also want to make sure there is plenty of space around the tub so that you can easily enter, exit, and put on/remove the cover.

No matter how or where the tub is installed, there must be access to the motor for servicing. Access panels or removable steps are easy solutions for tubs placed on the deck’s surface. If the spa is partially recessed, we suggest leaving at least side accessible. For a recessed spa, your builder may opt to frame out an access hatch or otherwise leave room around the tub’s edge so that the unit may be lifted straight up from its space.

The last thing anyone wants while walking to and from the hot tub is to get a splinter in their foot. Make sure the surface of your deck is smooth to prevent one.

With careful planning and the help of qualified professionals, a hot tub/spa can be a great addition to your new outdoor space. To learn more about hot tubs – and to download valuable safety information – visit the Association of Pool and Spa Professionals website.

if you want to keep leaves out of your hot tub, avoid placing it underneath a tree.

Ensure there is adequate room around the spa for the cover lift to function and air to circulate. On larger decks, consider traffic flow around the space.

Take note of prevailing winds. Locating the unit near the corner of the house tends to accentuate the wind, some builders say.

The spaces between the deck boards should be wide enough to let any sloshed-out water through, but not wide enough that someone might catch a toe in it. 1/4 an inch is usually a good way to go.

Many builders recommend installing the hot tub so that its edge is 17-24 inches above the decking. Guests can sit on the rim and swing around into the water more easily. For spas located on top of a deck, stairs are in order.

No doubt you’ve seen spas that are flush with deck surfaces – an elegant look but one that can prove hazardous. Children, in particular, are more likely to step on the cover or even fall into the spa. Of course, if you have children or expect young guests, a cover with a lock – and, of course, vigilant adult supervision — is essential.

Factor in the orientation of the sun and location of trees.

Hot Tub Deck Privacy

Don’t forget about the neighbors. A privacy screen, pergola or other design element will shield your space from the people next door.

No one wants their neighbors peeping on them when they’re relaxing in the spa – consider adding a privacy fence, foliage, or a pergola to give yourself some privacy. 

Orient your spa to maximize backyard scenery, but be sure the unit itself doesn’t interfere with that view when you’re inside looking out.

Different Names For Hot Tubs On Decks

There are a wide variety of hot tubs, and even this is an understatement. You may have heard of portable hot tubs, vinyl, and even inflatable hot tubs.

We’ll also only be using the term “hot tub”, and not “jacuzzi” or “spa” because Jacuzzi is an actual brand and a spa often references a more advanced type of in-ground hot tub with more features.

Hot Tub On Deck Ideas

Patio, Recessed, & Raised Decks

1. Raised platform hot tub design with horizontal stainless steel cable railing.

Spa Platform on a Modern Deck

Photo via Long Island Hot Tub

When building the new deck, a platform was made to hold the hot tub at a height conducive to regular use. When dining or lounging, the inviting hot tub is just steps away: ready and waiting. Integrate a horizontal stainless steel cable railing to give the design a modern look and feel. – Tip provided by Bill Renter, Long Island Hot Tub, New York

2. Small space with a deck.

Hottub Deck for a Small Space

Photo via Love Chic Living

For those who have a small space to work with, a simple deck around the hot tub is great for creating a more spacious look. Include plants, outdoor furniture, and other decor to make the space uniquely you…one you’ll love spending time in after a long day.

3. Think ahead before building a deck with recessed hot tub.

If you wish to “recess” the spa in the deck, you may want to consider how deep. Fully recessed hot tubs may actually make entering the spa a challenge. Homeowners may only want it recessed half way to allow easy access. Also make sure to allow clearance to the access panel for the spa to be serviced. – Mel Higgins, Aquarius Pools and Spas, Maine

4. Ensure your structure can support a hot tub.

Space Saving Deck with Inset Hot Tub

Photo by Better Homes and Gardens

For saving sight lines around small spaces, sinking the hot tub in the deck area is an excellent idea. When recessing your hot tub into a deck, leave about 16-18” rise above the deck to allow for the cover to fit over the hot tub when not in use. Keeping your hot tub covered when not in use will save energy, prolong the life on the spa and avoid unnecessary hot tub maintenance.

Key insights:

  • Sunken decks, if not structured correctly, can create additional stress you don’t want. When installing a hot tub in your deck, ensure the structure is stable to support the weight of a completely filled hot tub safely without shifting.

5. Adopt a short deck design to enlarge your backyard.

Short Deck with Integrated Hot Tub

Photo via Azek

Avoid harsh lines by designing a short deck which flows through a circular design. This short deck, composite design is stunning for creating a relaxing space for hosting dinner parties, enjoying time with family, or creating a space for relaxation.

6. Build a bench surrounding your hot tub.

Hot Tub Surround Bench

Photo via Archadeck of Central GA

If the sunken hot tub is too much work (or too high a cost), another option is to build a bench around the spa for a nice clean, modern look. For most people, composite materials are more functional to use when constructing an area outdoors or around a hot tub. If you decide to use wood instead, make sure the wood is properly sealed (i.e. tar paper). Your local home improvement store or contractor can assist you in what options fit best for your area’s climate.

7. Utilize a stunning elevated two step design for easy access.

Steps Around In-ground Hottub

Photo via Charles Hugo Landscape Design

Accent your spa with an elevated two step design for a more modern feel around your hot tub. The steps around the hot tub are not only excellent to assist you to enter or exit the hot tub, but can be a great spot to place a towel or drink.

Key insights:

  • Choose your location carefully, considering your access needs, landscape tastes, and lifestyle. One excellent option is to position the spa in a corner on your patio near your home for easy access all year long.

Maximize your views but don’t sacrifice function.

Incredible View from the Hot Tub and Deck

Photo via Arizona Hot Tub Company

Many folks love the idea of sinking a hot tub into a deck. This allows them to see a 360 degree view and really completes the outdoor living area. This style makes the hot tub appear like it was custom designed for you and your life, resulting in an amazing finished look. However, it’s important to not sacrifice function over form. Having an adequate access area to the equipment area is imperative to long-term happy hot tubbers! – Tip provided by Nick Kasten, Arizona Hot Tub Company, Arizona

9. Construct a multi-layered platform deck with gazebo.

Hot Tub in Deck with Gazebo

Photo via Allscape

Gazebos are an attractive addition to include in your deck design. This multi-layered short deck with gazebo is perfect for any space. Use various levels to enhance your deck’s appeal and to create specific areas for entertaining guests.

Key insights:

  • When building a platform deck, like the one above, measure the height and depth of the hot tub, then cut the pieces 2 by 4 material to construct the frame. Include the same number of pieces for the vertical pieces of the frame.

10. Raised short deck with accented seating.

Modern Short Deck with Benches

Photo via Fine Decks

Another stunning, modern design is this raised short deck design with accented bench seating. Incorporate greenery, outdoor furniture, and even a fire pit, to design a space to entertain guests. In addition, the built-in seating can be used as low railing to prevent against accidentally falling off the deck edges while conversing.

Wood, Composite, & Other Deck Materials

“Think outside the standard wood platform with smart design ideas for a range of settings and budgets.”  – This Old House

11. Skip the cost of stone and use travertine instead.

Travertine Pool Deck

Photo via Long Island Hot Tub

Incorporate travertine and black stone veneer panels to create a more elegant hot tub look. In this hot tub deck design, Long Island Hot Tub sunk the spa halfway into the ground then built a stone wall around the spa. – Tip provided by Bill Renter, Long Island Hot Tub, New York

12. Explore exotic hardwood materials.

Gorgeous Modern Hot Tub Deck

Photo via Nick Leith-Smith

Durable hardwoods like Iroko, Acacia and Ipe are ideal for exterior use and will stand the test of time. – Tip provided by Nick Leith-Smith, Architecture and Design, London

13. Capped composite decking.

Hot Tub Deck Rendering with Levels

Photo via Fine Decks

These days the majority of decking around hot tubs is composite decking. All capped composite decking is particularly popular.

Key insights:

  • When deciding on a composite wood, take into consideration the pros and cons of uncapped and capped composite. Uncapped composite is more vulnerable to staining, fading, mold, and mildew, whereas capped composite has a surface cover (similar to that on a golf ball) which contains UV inhibitors, anti-oxidants, and other products to enhance the longevity of the wood.

14. Wood gives your outdoor space warmth.

Modern Wood Decking Material

Photo by Jeffrey Gordon Smith Landscape Architecture via Houzz

Use wood to “…give the space warmth and rhythm while also distracting the eye from the different window heights. Interest is created by building out off of the existing walls, which have given depth to the space through the use of light-box windows.” – Tip by Jeffrey Gordon Smith Landscape Architecture, California

15. Blend wood and brick together in your deck design.

Deck and Patio Design with Wood and Stone

Photo via State-Homes

Mix the more industrial look of stone and the warmth of nature to create a stunning outdoor patio area. Accent the space with a trellis for plants and other greenery to add to the beauty of the space. Or, position your hot tub between the wood trellis for additional privacy.

16. Include a flowing fountain feature to amplify peace and relaxation.

Gorgeous Garden Elements inset in Patio

Photo via Madison Planting & Design Group

Water features are a wonderful focal point to include in your outdoor design. Plus, by incorporating the four elements (earth, fire, wind, and water) into your space, you’re involving all your senses and adding value to your property.

Key insights:

  • Add a foot path in your backyard design (earth), install a fire pit of tiki lamps (fire), hang wind chimes (wind), and include a fountain, pool, or hot tub (water) to enhance your outdoor space and reconnect with your senses.

17. Go modern with wood, multi-level decking.

Modern Hot Tub Deck with Lighted Steps

Photo via Nick Leith-Smith

By installing a multi-purpose, multi-level decking area, everything from seating, storage, outdoor showers, bbqs, bars and planting areas can be incorporated into a seamless design. – Tip provided by Nick Leith-Smith, Architecture and Design, London

18. Set your hot tub within a natural setting.

Natural Setting Hot Tub Patio

Photo via Long Island Hot Tub

Water features and backyard ponds are an excellent focal point for any time of year. With the right environment your hot tub can become its own sort of pond or feature. Add some natural boulders and planters around the hot tub to raise the spa up and make the hot tub experience an art form. – Tip provided by Bill Renter, Long Island Hot Tub, New York

Key insights:

  • This jagged rock faced design is perfect for creating a more natural feel around your hot tub. Mix in some plants and other succulents to make the area pop with color and appeal.

19. Incorporate faux stone in your design.

Stone Fencing Around Hot Tub and Deck

Photo via Genstone Products

Faux stone gives you the real stone look without the high price. Use faux stone in your hot tub deck design to create a unique look to your backyard patio and hot tub.

Hot Tub Electrical Requirements

For the installation, we also need to consider the hot tub electrical requirements.

We have discussed those requirements in this article, that are independent from all the calculations needed to install a hot tub on a deck from the structural point of view.

Source And References

  1.  “Tips to Improve Hot Tub Energy Use” (PDF). Retrieved 18 February 2022.
  2. Pacific Gas and Electric Company (May 12, 2004), Analysis of Standards Options For Portable Electric Spas (PDF), California Energy Commission, archived from the original (PDF) on 2006-10-06, retrieved 2022-03-09 (archived from the original).
  3. Katherine Wang and Joshua Keim (September 2007). Turning Up the Heat. Retrieved on 2022-03-10.
  4. “List of portable electric hot tubs approved for sale in California”. Archived from the original on Oct 27, 2008.
  5. California’s current appliance efficiency regulations. (2006).
  6. Megan Geuss (January 13, 2020), Updated hot tub standard could bring surprisingly big energy savings to states, Appliance Standards Awareness Project, retrieved 2022-05-14
  7. ANSI/APSP/ICC‐3 “Permanently Installed Residential Spas” (PDF), American National Standards Institute, January 8, 2018
  8. BBC (12 March 2013). “Stoke-on-Trent Legionnaires’ deaths: Report calls for hot tub review”BBC News. Retrieved April 20, 2022.

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