Putting such a heavy object on the bare ground is never a good idea. The ground shifts and sinks with the changing of seasons, as well as the heavy weight of a hot tub. This could cause preventable damage to your hot tub if you used a base on top of the ground.
A hot tub should not be placed on the ground and requires a base made of concrete, pavers, decking, or gravel. However, a portable hot tub can be placed on the grass for a few days if needed. To prepare the ground for the base, you need to dig 6 inches deep and place crushed stone down.
With so much information, it can be hard to discern what you can and can’t do with a hot tub. However, placing it directly on the ground is never a good idea. It will sink and ultimately crack the hot tub. Even with a portable hot tub, the vinyl can rip with an uneven surface. Installing a base is an alternative to placing a hot tub on the ground.
Can a Hot Tub Be Placed Directly on the Ground?
A hot tub cannot be placed directly on the ground. With the heavy weight of a full hot tub, it will sink into the ground and leave you with an uneven surface.
When a hot tub is filled with water, it can weigh a few thousand pounds and sits with a footprint of 12 square feet, leaving a lot of weight in a small area.
Larger objects don’t typically sink at an even rate as the weight settles. This leads to an uneven hot tub that occurs gradually over time, leaving you with a cracked shell or frame. An unstable base also places a lot of stress on the hot tub, both the frame and the actual shell.
When it is full of water, the chances of that shell warping or cracking is significantly increased since a hot tub is designed to take an even distribution of weight at all times.
Can You Put a Portable Hot Tub on Grass?
A portable or inflatable hot tub can be temporarily placed on the grass. But, like any hot tub, the weight of it will settle and eventually become uneven as parts start to sink into the ground.
If you’re renting a hot tub for an event or need a temporary location, the ground will work for a few days at maximum or risk ripping a seam. However, there are a few things you want to make sure of before filling it up.
Preparing for a Portable Hot Tub
First, you want to be sure the ground is compact. Fresh soil will sink considerably and shift under the weight of the hot tub, even if it is only sitting there for a few days.
You want to ensure the area is free of rocks, stones, and sticks or risk a hole in the hot tub’s shell. The ground also needs to be relatively level, so having a sloped location will not work, given that gravity and water tend to work together to create unfavorable situations.
Something else to consider is the health of the grass. Grass needs sunlight, and placing something heavy on top of it, even for a few days, will most likely kill the grass, leaving you with a large brown patch on your lawn for the rest of the season.
As the grass around the hot tub grows, it will puncture the vinyl of the hot tub, which is also why many portable hot tubs come with a liner to place on the ground first.
What is the Best Base to Put a Hot Tub On?
There are many different kinds of bases you can get for your hot tub, all with different pros and cons as well as aesthetics. Knowing which base is best for you depends on your location and needs.
Gravel is one of the most popular bases for hot tub owners, given its lower cost and excellent draining qualities. However, to use a gravel base, you will need to have a solid tamped down ground base beforehand, which will help with the leveling of the hot tub later on.
The rounded and smaller gravel stones offer an excellent water draining system so that it doesn’t collect under the hot tub and cause issues further down the line.
A gravel base won’t crack or break like other options and will mold to the base of the hot tub, creating a solid and firm platform for the hot tub to sit on.
A premade base (on Amazon), or spa-pad, is a prefabricated composite hot tub base that lets you quickly set up a hot tub on an existing platform, like a deck or concrete slab. It can protect the wood, concrete, stone, or paver stones from water or temperature damage and doesn’t require any maintenance.
The benefit of the pad is that it distributes the weight of the hot tub evenly and is strong enough to hold the hot tub when full of both water and people.
A deck will need to be reinforced or specifically built to hold a hot tub, as a standard deck only holds about 50 lb per square foot but needs to support 100 lb per square foot.
Having a deck built or reinforcing one can come at a higher cost, given that it is important to hire a contractor to go over the calculations and labor or risk a costly mistake if the hot tub can’t be supported.
Paver stones (on Amazon) offer a wide variety of customizable options from color to design and layout, but if you are going with this form of base, you need to make sure you pick pavers with no ridges or raised edges on the stones themselves. A flat surface is required, and this detailing can cause problems later on.
Cheap and attractive, paver stones are one of the most popular options for people to put their hot tubs on.
The last form of base is the concrete slab. Long-lasting and sturdy, it does come with a higher price tag. A concrete slab also prevents additional repairs to the utilities of the hot tub, usually underneath. Concrete also requires 30 days to cure before the hot tub can be placed on it.
How Do You Prepare the Ground for a Hot Tub?
To prepare the ground for your hot tub installation, you want to maximize its strength and stability. Therefore, the base should extend about 6 inches beyond the hot tub on all sides. You want to dig down at least 6 inches and create a level patch of bare earth free of grass, stones, or sticks.
Next, add 4 inches of crushed gravel and about 4 to 6 inches of your desired base, either paver stones or concrete. Although preparing the ground for the hot tub is easy, installing the base could be more time-consuming and costly, depending on the base you want.