An inground trampoline is a trampoline where the legs have been placed into a purpose built hole. The trampoline mat is either level with the ground, or sits just above it. It should have an enclosure net for safety, but it may not. And it’s generally more expensive than the regular above ground trampoline. In the UK, they are often called sunken trampolines.
Pros:
- An inground trampoline looks super fancy.
- Better landscaping. Putting the trampoline so that it is flush with the ground means that you can landscape around it better.
- The kids will probably use it more often. It’s easier to step on and off if it’s at ground level.
- Your yard doesn’t need to be completely level as you can create a level hole.
Cons
- They are more expensive to buy. The steel frame has to be much stronger and rust resistant, as the environment is likely be damper than for an above ground trampoline.
- They are more expensive to install in either cost or time. The hole needs to be dug and the walls retained. You will either need to pay someone or you will need to do this yourself by hand or with a mini-digger.
- They are not absolutely safe. There needs to be a gap between the mat and the retaining walls, so kids (and things) can still slip down. And, of course, you can still bounce off them from a great height.
- Things, pets, wildlife and kids can get trapped underneath, and it can be a BIG JOB to either take off the mat or lift out the entire trampoline to free them.
- Depending on the model you get, air vent pipes can add to the cost and maintenance of the trampoline
Are Inground Trampolines Safer?
Inground trampolines look like they should be safer. They are closer to the ground, so the kids can’t slip as they climb onto the mat.
But there are still ways that accidents can happen.
Kids can still slip down into the hole below. A regular trampoline might be 3 feet above the ground, so if it’s been raining or the sprinklers have been on, or even if they just have socks, the ladder can be slippery. However, an inground trampoline still needs to have a gap between the retaining wall of the hole, and the mat. It might be a small air vent gap, or perhaps even the hole wasn’t dug quite deep enough, and so it sits up a few inches too high. A small child can slip through a space as little as 5 inches. This is why swimming pool fences can’t have gaps of more than 4 inches.
If there is water in the hole that hasn’t drained, it could be a drowning hazard for toddlers who have slipped down under the trampoline. It will also be difficult to see them and find them in the yard.
There’s also a perception that because the trampoline mat is closer to the ground, there’s no need for an enclosure net. Depending on the size and shape of your trampoline, it is possible to get quite a good bounce up, and with a couple of kids, you could easily bounce each other off the mat from a great height.
Can I put a normal trampoline in the ground?
You can put a normal trampoline in the ground, but it’s not generally not a good idea. The frame is not designed for being in the ground, and the mat won’t give enough air exchange with each jump for a good recoil and bounce.
Regular trampolines vary in terms of steel quality and strength. A frame that isn’t galvanized properly by the manufacturer will rust quicker. If the steel quality is a poor alloy, or the steel thickness isn’t sufficient, it will also rust quicker.
As the trampoline is in the ground, it will be difficult to check on a regular basis how it is holding up. You might think you can commit to a regular inspection and maintenance check, and in the first year you might be right. But think about year five or year nine, the last thing you’re going to want to do is pull the trampoline out so you can get a good look over it.
They also have covers over the springs that deteriorate over time. This isn’t ideal on a regular above ground trampoline. But for an inground trampoline, when something important falls through the springs, you’ll have to get the mat off to access the pit. This feel reasonable if it’s a child, but will grow old real quick if it’s a toy.
How do you install an inground trampoline? A step-by-step guide.
The basic principle is to dig a suitable hole, reinforce the walls so that they don’t collapse. Ensure adequate drainage and lower the trampoline in. Here are the steps to follow.
- Contact your local city “Call before you dig” service (in the US, dial 811). Make sure there are no electric cables, sewer lines or other services underground before you start to dig. That would be awkward. Move any inground sprinkler systems.
- Make sure there are no overhanging branches. Check that it’s not right next to a fence. Try to choose a place where there are no big tree roots that would be dangerous to cut through. (DO NOT destabilise the tree next to the trampoline!)
- Mark out the size of the hole with spray paint. Put the top frame of your trampoline together. Put it over the patch of lawn where you want to install it. Get a line marking spray-paint can from your local hardware store. These are designed to spray upside down. Spray a few inches around the outside of the trampoline frame to allow for the pit wall reinforcements. This is the shape of the hole you want to dig.
- Now dig the hole. You can use a mini-digger over a few hours, or hand dig over a couple of days. For the mini-digger, you can often hire these from local heavy equipment hire places, and you’ll need the appropriate license. If you don’t hold one, one of your neighbors or a relative might.
- If you hand dig the hole, first remove any turf and put it to one side. You might want to keep this separate until the job is done. Then dig a hole, starting at one side. You can use a wheelbarrow to carry dirt out, or just pile it up beside the hole. Dig out to the edges you marked out previously, and dig down to the height of the trampoline frame. Keep at least some of the dirt close by as you’ll want to use if for backfilling the edges.
- For the depth – if you have a proper inground trampoline, it will have a mesh mat that is vented or ‘breathes’. This allows the air to escape through the mat. You can dig this kind of trampoline down until it is flush with the turf. If you are using an above ground trampoline, there will be a heavy pad over the spings. For this type, make sure that there are a few inches between the turf and the trampoline. If you skip this, you’ll find when you try to bounce, the air can’t escape, and you won’t bounce as well as you’d like.
- Check that the trampoline fits. Don’t start the pit reinforcement until you have done this step! Make sure the legs are on the trampoline, and lower it into the ground.
- Install drainage. If you have sandy soil, you may be able to skip this step. For regular soil, you might just want to dig down another inch or two, and add gravel or roadbase. Finally, if you have heavy clay soil or a high water table, you may actually need a drainage system such as a sump pump or drainage pipe.
- Reinforce the walls of the hole. This is critical. Otherwise, the first heavy rain will see the sides crumble into the hole. This can leave the sides dangerously exposed, and if enough dirt moves, make it impossible to bounce on the trampoline because too much dirt is below. You can either put reinforcement around the walls of the pit itself, and then lower the trampoline in. Or, drill and screw a wooden frame onto the trampoline legs, then attach metal sheeting to the wooden frame.
- Lower the trampoline into the hole. Check it is level. Don’t skip this step, or your kids will bounce straight off the trampoline every time!
- Backfill around the edges and replace any turf.
- If there is too much of a gap between the top of the trampoline and the hole, animals, birds or children WILL explore and fall in. You’ll spend far too much of your time detaching the trampoline mat and playing rescue hero. Use pool noodles, or lower your trampoline further and use vented spring covers to ensure air can transfer well.
- If you want, add the trampoline net.
Then, once the trampoline is in and level, call out “Go Forth, Kids!”, and they will be ready for hours of fun.
And of course, you might also decide to engage a contractor to install it for you!
How do you winterize an inground trampoline?
Similar to preparing an above ground trampoline for winter, you can take the mat off so that it doesn’t get weighed down with snow. You can probably leave the frame in the ground, as there is little danger of it blowing away in heavy winds.
You will want to mark out the trampoline hole with stakes and high visibility debris netting. This will stop you from falling into the hole when it starts to be disguised with a little snow.
Why are inground trampolines more expensive?
There are two components that make the price of an inground trampoline more expensive.
They use a higher-grade steel that is less likely to rust when placed in the ground. This is important for damp soils, moderate to high rainfall areas or even regions with snow.
The installation cost drives up the overall price. If you do it yourself, you might be able to spend only a few hundred dollars on a digger and materials for the wall reinforcement. However, you can easily spend over a thousand dollars to have someone install it for you.
Will my inground trampoline flood? And how to tell if I need drainage?
Whether or not your inground trampoline floods depends on the amount of rain you get, and how porous your soil is.
Flooding under your in ground trampoline is not good, as it makes it harder to bounce if you are landing in water (self-evident, right!), but also, will make your trampoline frame rust quicker. It’s super dangerous if there’s any chance that a toddler or any child can slip under the trampoline mat, land in a puddle, and not be able to climb out. Remember, a child can drown in less than 3 inches of water.
If you have sandy soil, you might not need any special drainage.
If you have regular soil, you’ll probably be able to get away with a small deeper hole in the center of the pit. This is called a “soakaway”. You fill the base of the pit with gravel or roadbase, and this helps the water move to the soakaway, and drain away slowly. The advantage is that you don’t have any puddling or pooling of water under your trampoline.
If you have heavy clay soil, you can test out if the above solution can work, but it’s pretty likely you’ll need to go all in on a solution. This might be a drainage pipe, with filter cloth around it to stop dirt getting in. This drainage pipe then needs to be dug out through a trench in the surrounding yard and emptied into a place LOWER than the base of the trampoline pit. It works by gravity.
Drainage solutions for an in-ground trampoline
If you know that you need a serious drainage solution for your inground trampoline, then you can look at other solutions. These include:
- The “sometimes” pump. When it rains, you can get a surface drainage pump, lower the drain pipe into the water, plug it in, let it drain out on the yard around the pit.
- The “permanent” pump. If you know you have a high water table, or water is permanently pooling under the trampoline, you can get a submersible pump, and leave it installed. These can either be turned on manually or automatically when there is water. I’d recommend having the automatic version, so that you’re not having to constantly remember to turn it on and off, or dashing out in the rain to adjust something.
Summary
For our Mission: Backyard Adventure, an in-ground trampoline is just perfect for the kids to get out of the house and moving around.
I love the look of an inground trampoline sitting flush with the lawn. They are safer for little ones to get on and off, and closer to the ground for any spills. They do take more work to set up and install. And they can be a bit more expensive if you get the steel frames that are designed to sit in the ground.
Overall, an inground trampoline is a great addition to your yard.
