Installing a hot tub on decking looks stylish and is practical to boot. But there are a few things you should be aware of before you place a home spa on any old deck.
Here’s everything you need to know about placing a hot tub on decking – as well as some design ideas for inspiration. Also view our garden ideas post for more hot tub ideas from the latest home spa installations.
Can you put a hot tub on decking?
A deck is the perfect base for a hot tub. It’s a smart and tidy location where your hot tub will look the part and flow with the rest of your outdoor space.
However, there are a few boxes your decking needs to tick if you’re going to sit a hot tub on it:
It needs to be reinforced
Your decking needs to hold up to the weight of your hot tub when it’s full of water and people, which means it will need reinforcing with extra support beams (more on this later).
It needs to be completely level
A deck needs to be completely flat if you want to install a hot tub on it or the water won’t be level in your tub – and might even tip out of one of the sides if things are seriously skew-whiff! In addtion, you’ll be putting unnecessary stress on your decking if it’s not level, which could cause you some serious problems down the line.
It needs to be made from strong and sturdy materials
A hot tub full of water and people is going to put your deck under considerable strain. If you’re sitting a hot tub on an existing deck, make sure to replace weathered decking and components like lag screws and joist hangers with new, strong, and sturdy equivalents so they’re up to the task.
Make sure existing decking is reinforced enough to support your deck as well by adding support beams.
It needs to be anti-slip
Water and any kind of decking that gets slippery when wet don’t mix. So, be sure to use anti-slip decking around your home spa to prevent any nasty accidents.
It needs to be near an electric supply
Your new tub will need to be wired up to a dedicated 220v power supply, so you’ll need one installed in your garden by a licensed electrical contractor.
It needs to be near a water source and drainage
Your hot tub needs to be within easy reach of a hose pipe and ample drainage for when you empty and fill it as part of your hot tub maintenance routine.
You need access to the electronics
Wherever you put your hot tub, you need to be able to access the electronics for maintenance and repairs and make sure it’s not a squeeze to get in and out of. So, leave at least two feet between your hot tub cabinet and any surrounding walls so you can get in and out safely and comfortably. And make sure there’s at least four feet of clearance on the side of your hot tub that contains the access panel so technicians have maintenance access to your spa’s control panel to make repairs.
Repair access is particularly important to keep in mind if you’re planning on sinking your hot tub into your decking. If this is the route you’re planning on going down, it’s a good idea to either make the panels around the top of your hot tub removable or install it near the edge of your decking so the side panel can easily be removed for maintenance and repairs.
Pick the perfect spot
Last but not least, make sure to mull over what’s going to be the best spot for your home spa.
It might not be possible with the space you have to play with, but the perfect place for a hot tub is a private spot away from where neighbours will be able to see. If you don’t have a space like this for a spa in your garden, it’s well worth thinking about building a hot tub shelter, installing a privacy screen, or growing some plants to obscure you.
Tucking your hot tub into an alcove is a great idea if you can, as it will protect you from the elements as well as lend some privacy.
It’s also worth keeping in mind that the closer your hot tub is to your house, the more likely you are to use it – especially in the colder months. So, all else being equal, it might be worth installing your decking and spa leading straight out from your back door.
And of course, looking out onto a border of beautiful flowers during your spa sessions is a lot nicer than staring at the side of your house. Don’t underestimate how much a view will improve every soak.
How to reinforce decking for a hot tub
A hot tub can weigh up to two-and-a-half tonnes once it’s full of water and people, so it’s crucial the decking you sit your spa on can support this kind of weight.
As a rule of thumb, the cross-members supporting a deck you’re placing a hot tub on should be 4” x 2” and no more than 18” apart.
We strongly recommend you go with a hot tub dealer that will check that your decking is a stable enough foundation for the home spa you have in mind during a site survey. But if you do choose to go it alone, here’s how to work out whether your decking is up to the task of holding up your hot tub:
Get your hot tub’s dry weight from the manufacturer’s handbook or website.
Look up your hot tub’s water capacity in its handbook or online. Water weighs almost exactly a kilogram per litre – so your spa’s water capacity in litres is how much the water will weigh in kilos when it’s full.
Work out the rough total weight of the maximum number of people that can fit in your hot tub. The average British man weighs 13.16 stone (83.6kg) and the average woman 11 stone (70.2kg) if you need to make a rough estimate.
That gives you the weight the section of decking your hot tub will be sitting on will need to support. Of course, it’s well worth baking a bit of wiggle room into your calculations here, as you definitely don’t want to exceed your deck’s load bearing capacity.
The next step is working out how much weight your deck can support, which is a lot more complicated. We recommend you follow this guide to calculating your deck load capacity if you decide to do this yourself, but strongly recommend you leave this to the professionals to sort for you. If you get this wrong and your decking collapses, you might not only hurt one of your loved ones, but you’re also sure to void your spa’s warranty.
How to sink a hot tub in decking
Sinking your hot tub into your decking looks spectacular. It’s the perfect way to blend your spa in seamlessly with the rest of your outdoor space without blocking the view of your borders when they’re in bloom. It also lightens the load on your decking, as your spa will be sitting on the ground with the decking built around it.
To sink your hot tub into your deck, pick the perfect place for your hot tub and then build your decking around it. If you’re sinking a hot tub into an existing deck, you’ll need to cut a hole the right size to drop your spa into, which is a much more difficult affair.
Then you need to decide how far you’re going to sink your spa:
Fully sinking your hot tub in your decking
Fully sinking a spa so your decking goes up to the edge of the tub is a great way to add a touch of glamour to your garden. One thing to keep in mind is that while you can add a spa to an existing deck, it’s far easier to install them both at the same time. As we touched on above, be sure to build repair access into your sunken hot tub designs.
Half-sinking your hot tub in decking
Another option is half-sinking your hot tub so the decking goes halfway up its cladding. This adds a splash of style to your outdoor space while making your spa a lot easier to slip in and out of than if it was fully sunk, making it the perfect option if accessibility is an issue for anyone in your household.
Whether you’re planning on half- or fully-sinking your hot tub into your decking, it’s crucial that you account for ample repair access. That means room for two technicians to lower themselves down and access at least the side of your spa with the control panel for maintenance and repairs.
Sink a hot tub into the corner of your decking and you’ll always be able to remove the side panels for repair access, meaning you’ll never have to go through the hassle of removing your hot tub for basic maintenance and repairs.
On the other hand, if you don’t accommodate for repair access, you’ll have to remove your hot tub from the ground to make even basic repairs. You might get lucky and never need to do this – or it could be a constant headache that costs you an arm and a leg over the years.
With all this in mind, the site visit that any quality hot tub dealer will offer as part of their services is a crucial step in having a spa sunk into your decking. Make sure to follow the technician’s guidance on the best option when it comes to sinking your hot tub here, even if it isn’t what you’d envisioned. Going against their advice could cost you a pretty penny down the road.
Hot tub on decking ideas
Now that you’re up to speed on the dos and don’ts of sinking your hot tub into a deck, let’s look at some hot tub decking designs to help inspire your garden renovation:
Hidden hot tub in decking
Sinking your spa into the ground and then surrounding it with decking at ground level is undoubtedly the most spectacular way to install a spa in your garden.
Placing it on the ground and then building a deck around it is another incredibly attractive way to showcase your spa.
Lean on your garden’s features
If your garden already has a raised section or is on a hill, sinking your hot tub into the highest area is a great way to disguise it without wholesale landscaping work.
Look for layers
Add visual layers that draw the eye up to a focal point by installing a raised deck with your hot tub sunk into it at the bottom of your garden.
Cleverly conceal things
Creating a custom cover for your sunken hot tub cladded in decking is a great way to make your spa blend in seamlessly with the rest of your outdoor space when you’re not using it.
Hot tub on composite decking
Composite decking is non-slip, low-maintenance, and incredibly durable, making it the perfect pick to sit under your spa. Plus, it makes for a particularly fetching foundation for a hot tub if you match – or complement – the colour of its cladding with your composite decking.
Keep things close to home
Install your hot tub on a deck that your back door leads straight out onto and you’ll be able to slip straight back into your house after winter and nighttime dips.
Find a natural alcove
Tuck your hot tub into a corner of your garden for privacy and plenty of protection from the elements.
Bring things together
Sitting disparate pieces of your garden on the same decking will help bring them all together stylistically and give your outdoor space a cohesive feel.
Create a luxurious getaway
Adding some plants and furniture to the decking where your hot tub sits, can transform it into a luxurious sanctuary you can escape to any time you need to relax. No matter what life throws at you, you’ll always have this spa shangri-la to kick back in and let the worries of the world drift away.
Let there be light
Installing some LED uplighting around your hot tub will really show off your decking and spa after the sun sets. It will also help guide you to and from your hot tub during nighttime soaks.
Erecting hot tub housing around can transform your spa into your own private retreat. It will also protect you from the elements – and the sun’s rays – during your soaks. Spa housing is also an affordable way to add some privacy to your soaks if you don’t have a convenient alcove to tuck your spa into, while inside the roof is a great place to install lights to add ambiance to your night-time soaks.
Step it up
Steps can make your spa a stylish feature – and more accessible. Wooden steps leading up to a spa clad in wood cna look particularly slick.
Make a connection
If your decking is at the back of your garden, it’s a good idea to lay down a path there so you don’t drag dirt and debris into your hot tub with you. This will also draw the eye to your deck, which works particularly well if you add some uplighting to it as well.
You can also extend the decking so it connects your patio or back door straight to your tub for a similar effect.
Match things up
A hot tub with wood – or composite wood – cladding can look particularly fetching on decking, as they complement each other perfectly.
Tie it in with your pool
If you’ve got the budget and space, installing a pool in your garden alongside a hot tub really is the height of luxury. And surrounding them both with the same anti-slip decking will help tie them together stylistically – even if they’re in different parts of your garden.
As you can see from these design ideas, placing your hot tub on decking can look seriously impressive. But there’s plenty you need to keep in mind to make sure your deck can support the weight of your home spa.
Follow the advice we’ve laid out in this guide – and follow the advice of a WhatSpa? approved dealership’s technicians – to make sure installing your hot tub on a deck goes well.
And be sure to pick up your free copy of WhatSpa? magazine for help picking the right hot tub for you and for the latest hot tub reviews – whether you choose to place it on decking or not.
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I am the Editor-in-Chief at WhatSpa? Media Group and have been actively involved in the hot tub and swim spa industry for over 20 years. I fell in love with hot tubbing in 2002 and since then have dedicated my career to helping millions of hot tub buyers to make more informed choices when navigating their buying journey.