Discover: What is the difference between a FlatGround and an inground trampoline?

In short: What is the difference between a FlatGround and an inground trampoline? In this blog, we clearly explain how the installation height influences the jumping experience, safety, and costs – and what that means for your garden.

We compare the most important factors such as digging depth and mounting height, air displacement under the trampoline, price, and maintenance. An inground trampoline usually rises 20 to 27 cm above ground level and requires less digging and soil removal, while a FlatGround lies completely flush with the grass, looks cleaner, but requires a deeper pit and more work.

You’ll also find practical tips on dimensions, drainage, the use of weed membrane, and fall zones according to relevant safety standards. Continue reading for a step-by-step digging guide, installation advice, and how to choose based on your garden and budget.

What is the difference between a FlatGround and an inground trampoline?

The main difference is the mounting height: a FlatGround lies completely level with the ground surface, while an inground trampoline typically sits 20–27 cm above the ground.

So what is the difference between a FlatGround and an inground trampoline? In practice, this means that a FlatGround is placed fully inside a pit and therefore requires a deeper and wider excavation, while an inground trampoline stands on short legs that rest on the edge of the pit. Both options are popular in the Netherlands and Belgium, but each requires different preparations in terms of digging, drainage, and ventilation.

Short overview of the key differences

• Mounting height: FlatGround = 0 cm above ground; Inground = ~20–27 cm above ground.
• Digging depth: FlatGround requires a deeper pit (up to ~90 cm in the centre for larger models); inground is less deep (often <70 cm).
• Airflow: inground allows air to escape through the sides; FlatGround must ventilate through the jump mat or special air channels.
• Cost and labour: FlatGround is more expensive and labour-intensive; inground is often cheaper and easier to install.

How does installation height affect the jump feel and safety?

The installation height directly affects how the trampoline feels and what safety measures are required.

An inground trampoline often feels more airy and responsive because air can escape through the sides, creating a ‘classic’ bounce. A FlatGround relies on air release through the mat or frame edge. If ventilation is insufficient, an air pocket forms and the trampoline feels stiff or dull.

Safety: fall height and fall zones

Note: Etan applies a fall zone of at least 1.5 metres around an inground trampoline, measured from the outside edge of the trampoline padding.

• Fall zone width: at least 1.5 metres (more is better and often recommended).
• Required cushioning: material in the fall zone must absorb a critical fall height of 1.5 metres.
• Surface and levelness: the surface may vary up to approx. 50 mm, making sand or wood chips sometimes sufficient.

Practical safety tips

• For inground: a safety net is often required for models certified as children’s play equipment; sports models are sometimes used without a net.
• For FlatGround: ensure the padding sits flush with the lawn; be careful to avoid lawnmower damage.
• Always: keep 2 metres free from obstacles such as fences or trees for additional safety.

Why does the required digging depth differ so much between the two types?

The depth differs because a FlatGround places the entire frame inside the pit, while an inground trampoline only requires a bowl-shaped pit beneath the jump area and the legs stand outside of it.

For an inground trampoline, you dig a shallower, bowl-shaped pit that gets deeper towards the centre; for FlatGround you dig out the full frame diameter and create a plateau or base for the frame. As a result, FlatGround requires significantly more soil removal.

How much soil is removed from the garden?

The amount depends on the size. Example estimation:

• Ø 300–380 cm inground: relatively little soil, pit depth around 60–70 cm in the centre.
• Ø 380–430 cm FlatGround: much more soil; 75–90 cm depth may be needed in the centre, especially for larger models.

Drainage and groundwater: what should you watch for?

FlatGround is more prone to water accumulation because the pit is deeper; therefore drainage is sometimes required.

• Sandy soil: usually provides good natural drainage.
• Clay soil: install a drainage pipe system or consult a landscaper.
• Simple tip: drill three holes in the lowest point and fill with gravel so water can drain away.

What costs, materials, and maintenance do both options require?

FlatGround is usually more expensive in materials and labour; inground is cheaper and requires fewer resources.

The most common cost factors include digging work, soil removal, drainage, weed membrane, and possible formwork (for rectangular models).

Maintenance and points of attention

• Weed membrane: recommended under both types to prevent weed growth (install with 10 cm overlap).
• Inspect foam and rim: some FlatGround ventilation systems expose the foam to more UV, causing it to wear faster.
• Lawnmower caution: on a FlatGround, the rim may be damaged if you mow too closely.

Common issues

• ‘Pop’ noise or stiff bounce due to insufficient ventilation.
• Risk of wall collapse with deep pits without proper reinforcement.
• Damage from kids riding balance bikes along the edge (more common with FlatGround).

How should you prepare and install step by step?

Start by choosing the location and determining exact dimensions; this prevents many mistakes and saves work later.

Check our digging instructions and the model-specific manual beforehand; these list minimum depths and edge measurements per size and brand.

Step-by-step digging guide (short)

1. Choose location: maintain 2 metres distance from fences and obstacles.
2. Mark the outer diameter using the supplied tape measure.
3. Dig in a bowl shape: shallower at the edges, deepest in the centre (follow manual).
4. Install weed membrane and any necessary drainage.
5. Place the frame on the plateau (FlatGround) or position the legs on the edge (inground).
6. Check levelness and fall zone and install the padding and safety net if applicable.

Tips for DIY installation and when to hire a professional

• DIY digging is perfectly fine for smaller models and loose sandy soil.
• Use a mini-excavator for large sizes or clay soil; manual digging is exhausting work.
• We recommend hiring a professional if there is already an existing pit; poorly refilled ground can cause later issues.

Which option suits your garden and budget?

Choose inground if you want less digging work, prefer a classic bounce, and want to reduce costs; choose FlatGround if you want a clean, low-visibility finish and your budget allows it.

Checklist to help you choose

• Do you want minimal visible height? → FlatGround.
• Do you want less digging and lower costs? → Inground.
• Is groundwater an issue in your garden? → Inground has fewer drainage concerns.
• Is aesthetics important (flush with lawn)? → FlatGround – but expect higher cost and more work.

Note: incorrect pit depth or poor ventilation can significantly reduce comfort and trampoline lifespan.

At Etan, we find that many customers choose the solution that best matches soil conditions and intended use after receiving advice. We always recommend considering who will use the trampoline and what size fits best in your garden. When in doubt – feel free to contact us!

At Etan, we have been advising and installing inground and flat-to-the-ground trampolines since 1988; rely on our experience for a safe and durable setup of your garden.

Conclusion

In summary, installation height – FlatGround flush with the lawn, inground approx. 20–27 cm above the ground – mainly determines bounce feel, digging depth, and ventilation. A FlatGround requires deeper excavation, more soil removal and often extra drainage, while an inground generally requires less digging and has lower installation costs. Safety remains essential: keep at least 1.5 metres of fall zone (preferably more) and ensure the surface meets NEN-EN71-14 impact standards. Also ensure proper ventilation; insufficient airflow causes stiffness or a ‘pop’ sensation and reduces lifespan. Choose inground when space for digging is limited, groundwater is high, or cost matters more; choose FlatGround when aesthetics and a lawn-level finish are the priority and you have the budget and time. Review product pages, digging guides and manuals for model-specific depths and fall-zone requirements to make a well-informed choice for your garden.