Can a hot tub sit on gravel? We were wondering the same thing when helping friends plan their hot tub location. Buying a new hot tub is an invigorating experience.
Just thinking about the many nights you and your family and friends will spend relaxing in a hot, bubbly masterpiece is enough to make anyone overjoyed. But buying the hot tub is only half the battle- where are you going to put this giant thing, anyways?
Short answer is: Yes. Gravel is an excellent base for hot tubs because it allows for drainage of water while being sturdy enough to handle the high weight of a hot tub.
While some people may think that their deck or patio is the go-to placement for their hot tub (due to convenience and aesthetics), gravel may actually be a better option. We’re going to discuss why gravel is a superior choice for hot tub placement.
First things first, we need to consider the weight of the hot tub. Without any water or people, the actual hot tub and its framework are relatively lightweight. Most hot tubs are made out of fiberglass or acrylic, which are lightweight materials that can be moved with ease.
This makes people think that their hot tub doesn’t need too much of a strong base, as it’s not as heavy as you might imagine. But when you add heaps of water and several people into the equation, the hot tub gains hundreds of more pounds.
With that much weight, you need to make sure you have a solid foundation for the hot tub to sit on.
Options for Hot Tub Placement
- Patio or deck. This is almost always the go-to placement for hot tubs. It’s convenient, it looks great on the deck, and it’s going to be the main attraction for gatherings. If you’re placing on a patio or deck you must take into consideration the weight, and make sure the structure is sound enough to support it or you may cause damage.
- Flat surface. Have a spot in the backyard with some grass? Maybe just dirt? While this may seem like a good solution, the weight of the hot tub can actually cause the ground to sink or shift over a long period of time, causing damage to the hot tub and the ground.
- Concrete. One of the better options is concrete. It’s relatively easy to pour a slab of concrete in the backyard for your hot tub. It’s incredibly tough and can support the largest, heaviest hot tubs.
- Hot tub support pad. Some companies have created actual pads designed for supporting hot tubs. Of course this is an excellent option, but it might not have the aesthetic qualities someone is looking for in their backyard.
Gravel is the Best Option
Concrete is undeniably the second best choice for hot tub placement, but at the top of the list is gravel and here are a few reasons why:
- Gravel has the ability to drain water, which is imperative when dealing with a hot tub. Other materials for placement don’t allow draining. With gravel, water can be drained from the hot tub and it will drain it with ease.
- Gravel is also aesthetically pleasing and can be placed in virtually any backyard and look great. It complements a variety of backyard designs.
- Gravel is easy to install. Gravel is a quick option that can be installed in a few hours, unlike other options that may require more time and effort.
- Gravel won’t end up cracking over time like concrete. This is due to the fact that gravel allows for ample drainage, rather than sitting on the surface. Concrete will crack over time with all of the excess water remaining on the surface.
- With all of the tiny pieces involved in a gravel base, gravel won’t shift over time like some other materials.
- Gravel will mold to your hot tub, which means you won’t have to worry about the hot tub becoming unstable or moving over time. The gravel molds to the base, creating a solid, firm platform for sitting.
- Lastly, gravel is relatively cheap. It’s one of the cheaper options for hot tub bases, but it still remains powerful and sturdy enough for large, heavy hot tubs.
How to Install a Gravel Hot Tub Base
Thinking about using gravel as a base for your hot tub? Excellent choice- but of course you need to know how to install it. Here’s the step-by-step guide for installing a gravel hot tub base:
- You need to know the dimensions of your hot tub. Measure the hot tub and have exact measurements. You will want to have a few extra feet around the hot tub to place gravel for draining and aesthetic purposes.
- Decide where you’re going to place the hot tub in the backyard. Make measurements on the ground using spray paint, a can of paint, markers, etc. Make distinct borders.
- At this point you will begin digging into the earth to make room for the gravel layers. You want to dig out at least 6 inches using a shovel.
- (Optional) Place a layer of landscape cloth on the bottom of your hole. This is completely optional, but can help with keeping weeds at bay underneath the gravel.
- Fill in the excavated area with gravel. Some people will choose to fill the hole completely with medium grade construction gravel, while others will want a top layer of pea gravel. It’s completely up to you. Find out the best wheelbarrow for this project.
- If you’re going the pea gravel route, add only 4 inches of medium grade construction gravel. You will fill the rest of the area (2 inches) with pea gravel.
- Smooth out the surface with your shovel. It’s important that the hot tub sits on a completely level surface, so take time to ensure all pieces of gravel are flat and aligned on the corners.
Things to Keep in Mind
- Always make sure that you’re constructing a gravel base on a completely flat and level surface. Trying to create your base where the earth is bumpy, hilly, or has other deformities may cause the hot tub to not work properly or be damaged. A level area is key to a successful hot tub base.
- Construction gravel isn’t the most pleasing to the eye. You can choose to use this type of gravel to fill the entirety of your base, but it doesn’t have to be. If you want a more beautiful landscape for your hot tub and backyard, then fill the top of the area with pea gravel or another refined gravel.
- Make sure you are digging at least 6 inches for your base, but nothing more than that. Without enough gravel, drainage can be compromised. With too much gravel, the hot tub base may become too soft and cause damage over time.
- Also make sure you have enough room surrounding the hot tub, especially if you have a hot tub with gazebo covering to allow for draining. There should be enough space to step outside of the hot tub and walk a few steps before returning to the yard/deck/patio.
- Gravel should be completely flat and level before placing the hot tub to avoid damage. Take extra care to level it with your shovel and ensure there are no high spots.
Buying a hot tub is exciting, but it can be challenging to decide where to put it. You need a structurally sound area that can handle the high weight of a hot tub.
You can feel confident placing your hot tub on top of a gravel surface. Make sure the gravel is 6 inches deep and completely flat and leveled before placing the hot tub on top.
Thanks for the article. I went with a stone patio for my hot tub. The delivery guys just dumped and left. Once I started filling I have a low spot opposite of my filter. I want to adjust the tub. What’s the best way to get under it and shift some stone? I either need to raise the back corner (I think more difficult) or lower the front corner. Is it safe (emptied and breaker out) to dig out the corner and side to shift stone?
Hey Kyle, yeah you’d definitely want to empty, shut off the breaker and then do your shifting around. Then it would be easier to dig out the higher back end to get it level with the other, lower corner than try to build it up. And get a long level to make sure it’s level all the way around. Either get a 4 or 8 foot level or get a really straight board to go across and put your shorter level on top.
Thanks guys. I framed 4×4 with a 4” pea gravel base on flat earth. ( not dug out). When delivered the tub was slid along the gravel. The tub was leveled out before they left. Just asking as a first time tub owner anything I should concern myself with in this scinereo
How did it last ?
Luke Andrews says
Hi I dug out and used all pea gravel. Is this gonna come back to haunt me? Still waiting on delivery of hot tub, so able to make a change if necessary. Thanks in advance for your help!
Keith Kane says
Just a heads up, the 4″ of crushed gravel is used for establishing a firm level base that drains easily. The 2″ of rounded pea gravel is so that when installing, the tub can be further leveled, since the round stones will give a bit when trying to get level, whereas the crushed stone tends to lock in place. And after install it does look better.
Putting down 6″ inches of pea gravel only is not a great idea.
So is the larger stone placed in first then smaller pea gravel on top to get in crevices? Or is it pea gravel as base first then larger stone above it? Can we use Long Island pea gravel and 1 1/2 inch Long Island rock?
Jena Slocum says
Thanks for your question, yes start with the larger rocks first, then fill in all the gaps with progressively smaller rocks. Any type of rock should be ok as long as you get the gravel level for the swim spa to sit on.
Alice Carroll says
I agree that crushed stone can be quite aesthetically pleasing on a backyard. I’m thinking about getting some soon in order to have a nice divider between my hot tube and my garden. Making the divider made out of organic materials will make the hot tube look quite natural to be there beside the greenery.
Gregg Sadler says
Can I make a deep gravel pad. I want to come off a slope. 6 inches deep on one side and 18 inches deep on the other. I have a slope coming off my deck before my patio, which I just made with 304 gravel and pea gravel raised 4 inches above the grade ( used 50 lb retaining wall block one level high to hold in the gravel). I would use the same blocks to “frame in” the compacted gravel. Pea gravel about an inch to two inches on top.
Jena Slocum says
Hi, thanks for your question. As long as your slope is properly supported with the retaining wall blocks, you can use a combination of soil and gravel that is compacted well to level your area for the hottub.
So my plan is to start with 6″ of 5/8 minus, an inch of sand and 2″ pavers on the surface. Any issues with that?
Jena Slocum says
Hi, thanks for your question and good luck with your project. I would think 3-4 inches of the larger gravel will be fine, with the leveling sand on top for the pavers.
Cindy Stevens says
I have a sloping back yard and want a swim spa. Will I need a retaining wall to keep the flat area from riding on the far side that slopes down? And what would be an inexpensive way to do this as I’m assuming I will need some sort of support to keep everything level. Thanks!
Jena Slocum says
Hi, thanks for your question. Depending on the slope of your yard, you could use retaining wall blocks up to 2-3 feet high which are fairly easy to install. If you need a higher retaining wall, I would call a landscape expert.
This article is very timely. My hot tub is coming in a month and I need a plan!
Since I’m already digging, I’m thinking of expanding the pea gravel area to include additional entertaining space.
I’m planning to dig 4”, remove the turf, line the outside with landscaping trim, lay down fabric, pin them in, then add 4” of pea gravel. Reading your article, I’m now thinking of 2” construction gravel on the bottom then 2” of pea gravel.
1. Having a bigger area (16 x 16 )than one specific for hot tub( 9×9) – any issues I should think about?
2. 4” of construction gravel base vs 2”- big difference?
Jena Slocum says
Congrats on the new hot tub!
1. No issues for the larger gravel area but do think about having some type of stepping stones as the gravel is uncomfortable on bare feet depending on the type of pea gravel.
2. I think the 4″ is better to support the weight of the hot tub, but that also depends on how level your ground is and what type of soil you have.
Thanks for the article. Question; would HPB be a good choice of aggregate to use for the base at 6″ depth?
Jena Slocum says
Thanks for the comment. I’m not as familiar with HPB base as regular gravel but as long as it is stable and and contained, I don’t see why not.
What if I have just pea gravel and no construction gravel would that be ok under my 7×7 hot tub?
Jena Slocum says
Hi Holly, thanks for the question. I believe your pea gravel will be fine. Most gravel designated as construction, I believe, is crushed limestone or crushed recycled concrete. I’m not sure there’s much difference when it comes to using it under your hot tub.
what are the max dimensions would you say crushed gravel+pea gravel are appropriate for? i am getting a swim spa, but it is the smallest offering at 12 x 8 feet and at capacity water+people looks to be about 15,000 lbs
Jena Slocum says
Hi Corey, thanks for the question. As long as you have at least 6 inches deep gravel spread over the entire swim spa plus a foot or two extra around the edges, you should be fine.
Rob G says
Is there any concern about the gravel and the warranty of the hot tub?
And if I use pavers, how do I get them placed and level?
Jena Slocum says
Hi Rob, thanks for the question. You should always check with your hot tub manufacturer before placing the hot tub on gravel due to warranty concerns. If using pavers, you will still need to use gravel as a foundation and make sure your pavers are the proper thickness to handle the weight. Again, check with the manufacturer for specifics.