We can’t tell you how many times in our years of reviewing hot tubs, we’ve been asked, “can you put an inflatable hot tub on gravel ?”
The answer is a resounding yes! You can place the inflatable hot tub directly on top of the gravel, use a gravel pad (we’ll go into those later) or sit standalone hot tub pads on top of a gravel base.
Either way, it’s one of the top foundations and base options.
This article will uncover why you should consider a gravel base for your new inflatable hot tub; we’ll see if gravel pads are better and even show you how to install a gravel hot tub base.
Can You Put A Hot Tub On Gravel?
Many people opt for a decked spa base or patio pavers as a hot tub base, but a gravel base might be a better option for a few reasons. It provides the proper drainage for your hot tub and is sturdy enough to cope with a large hot tub filled with water and people. Plus, it looks good in almost any outdoor space.
What Are The Benefits of an Inflatable Hot Tub on Gravel?
Gravel is one of the best bases for a hot tub if installed correctly and it’s affordable. Here are just a few benefits of using gravel as a base for hot tubs.
Great drainage
Gravel provides ample drainage for a hot tub, which is essential for a hot tub base. It also makes it easy when you need to drain the hot tub as the water will disperse without flooding the surrounding area.
Lots of choices
A pea gravel base can come in many different colours and styles, so it will look good with any hot tub and in almost any landscaping design, from country gardens to modern built-up urban designs.
Quick and easy to install
Gravel or crushed stone is quick and easy to install, taking only a few hours compared to some options, like patio pavers and decked areas which can take days.
Affordable
As well as being able to support heavy hot tubs gravel is also cheap, making it ideal for those on a budget. You can save money further by choosing construction gravel for the base layer and fancier pea gravel for the top layer around your hot tub.
Versatile
The fact that gravel is so versatile makes it one of the best hot tub bases. It will mould to the base of the spa providing a solid foundation and if you store away the spa for part of the year, it can become an attractive seating area.
Long-lasting
Unlike concrete bases, gravel won’t shift around your hot tub or crack over time. This is because the tiny pieces conform to the shape of the tub, meaning it’s one of the longest-lasting options for a hot tub.
Cons Of Placing A Hot Tub On Gravel
Water will encourage weed growth.
One of the most significant issues when placing a hot tub on gravel is that the small stones do little to prevent weed growth and with all that hot tub water splashing around, it’s the ideal environment for these pesky plants to pop up.
This can be avoided by using a good quality weed membrane before filling it with gravel or coating the gravel surface with resin.
Sharp gravel may burst the material.
Not all gravel is smooth; some stone chippings are granite and marble and can be extremely sharp. Whilst this might be ok for hard-sided hot tubs, an inflatable hot tub spa won’t last long on a rough surface.
Even though they are made of durable vinyl and PVC, an inflatable hot tub can be easily punctured by sharp stones.
Not great for bare feet
If you’ve ever walked on a shingle beach, you’ll know gravel is not the most comfortable surface for bare feet. However, this is not too much of an issue with pea gravel and, like eliminating weeds, can be entirely overcome by binding the gravel with resin.
Hard to keep clean
Finally, and not one to be overlooked, is that gravel, unlike pre-made spa pads or concrete pads, is hard to keep clean.
This might not seem like a big issue, but over time, that accumulation of dirt and debris will be transferred from your feet into the hot tub, causing hot tub water quality issues and possibly even posing health risks.
However, you’ve probably guessed it? Resin can be the solution again and finishes off a gravel spa pad beautifully.
How Do You Build A Gravel Hot Tub Pad?
Installing a gravel or crushed stone base for a hot tub is a fairly straightforward process that requires careful planning and attention to detail but provides a strong foundation for your tub.
Before you start, pick a completely flat location with no tree roots nearby.
- To get started, you will need to work out the dimensions of your hot tub and mark the area you plan to install the hot tub with spray paint.
You then need to calculate how much gravel you require. Not enough gravel may compromise drainage, whilst too much gravel will make the baseless stable and cause sinking over time.
It’s also a good idea to add a few extra feet of gravel around the inflatable spa so you can drain water away and avoid the area becoming muddy. - Next, you will need to begin digging; we recommend a depth of 6 inches below the ground’s surface to allow room for the gravel layers and to allow for hot tub drainage.
We also advise using a good-quality weed membrane underneath the base gravel level to prevent weed growth around the hot tub. - You then need to line the perimeter with pressure-treated timber to create a frame which will prevent loose gravel from escaping all over your garden and becoming unstable. Alternatively, you could purchase a plastic grid.
These usually come in interlocking squares, which are strong enough to hold the entire weight of even the largest spas, are weather-resistant and give the gravel some structure. - Once your gravel base is ready, you can begin filling it with larger construction gravel mainly made up of crushed limestone or recycled concrete as the bottom layer, followed by a layer of smaller pea gravel on top.
This is because construction gravel isn’t particularly attractive and may have sharper edges that could damage the spa. - Finally, be sure you have a completely flat and level surface before placing your hot tub on top of it. Most hot tubs come with a ground mat to provide a smooth surface for the spa to sit on and an added protection layer.
With these steps followed carefully, you should have no problem installing a solid base that will help protect it from damage and ensure long-lasting performance for years to come.
Gravel hot tub pads
As we’ve touched on above, in some cases, instead of framing the hole’s perimeter with wood, you could insert a plastic hot tub base, this grid sits inside the space and you place gravel in each section. Otherwise known as Geocells, these can support even the heaviest hot tubs.
Although gravel has a high crush strength, it can still be disturbed by foot traffic or placing heavy objects on it but combined with a gravel pad; the tiny pieces become incredibly stable.
You would lay a gravel pad precisely the same way as a standard gravel base; just be aware it can double the cost.
What’s the Best Gravel For Hot Tub Base?
The best size gravel for a hot tub base is between ⅜ – 1 inch because it allows for better drainage than other sizes.
Although many hot tub owners prefer to use medium-grade construction gravel as the bottom layer as it is cheaper, they use the smaller and much smoother river wash or pea gravel for the top layer.
How Much Will It Cost?
Gravel is cheap and you can save money even further by using medium-grade construction gravel under the slightly more expensive pea gravel layer for your hot tub platform.
For an area of 8 ft x 8 ft, you would need approximately a tonne and a half and if you fill with 2-thirds aggregate and then pea gravel on top, it can cost less than £100, which is a bargain when you compare it to the price for installing a patio for your hot tub.
Gravel Stockists
One of the advantages of using gravel as a hot tub pad is that it is readily available either in small 25kg bags or can also be delivered in larger quantities of 850kg or tonne bags.
Below are just some of the places you can purchase gravel for your hot tub base.
- Wickes
- Jewsons
- B and Q
- Travis Perkins
- Amazon.co.uk
- Buildershop UK
- Garden centres
Should You Use A Ground Cloth?
We would always recommend using a ground cloth if you have opted for a gravel hot tub base. Not only does it prevent damage to your hot tub from sharp objects, but it also helps to retain heat, a significant factor when considering your hot tub running costs.
You can buy ground cloths for hot tubs cheaply, but we’ve found interlocking foam tiles like the ones used for children’s playmats work well also.
Key Takeaways
Gravel makes an excellent base for any hot tub and is one of the quickest and easiest options. Not only that, it provides all vital drainage from your hot tub and can be used on its own or with a standalone base popped on top to protect the spa’s bottom.
A hot tub is a significant investment, so the last thing you want is another expensive bill for your hot tub spa pad and believe us a reinforced deck or sleek Indian Sandstone patio doesn’t come cheap. A pea gravel base for a small hot tub can cost less than a family meal.
Installing a pea gravel hot tub base is a breeze all you need is a shovel and a compactor to ensure the top layer of the hot tub pad is completely level.
If you construct a hot tub pad from gravel, you will have a huge choice of colours. From natural brown tones to minimalist black and white or more vibrant shades, there’s something to match every hot tub and suit every outdoor space.
If you need to learn how to safely set up your spa with the correct installation, then head over to our main page where we break it down for you.
Last Word
It can be tricky to decide where to put a new hot tub.
Along with needing a structurally sound surface unlike grass that can accommodate the not-so-inconsequential weight of a full inflatable hot tub, you will need to consider hot tub drainage and somewhere completely level for the hot tub to sit on.
A gravel base is top choice for an inflatable hot tub, it ticks all of the boxes above as well as being cheap, aesthetically pleasing and a cinch to install before purchasing a hot tub.
Like any base you choose, there are drawbacks, such as weed growth and the fact that gravel isn’t the most comfortable on bare feet, but these are easily solved with a ground mat and a bottle of white vinegar.
You can feel confident when you have a gravel hot tub base that you’ve nailed your hot tub placement.
