Building a padel court · 27 August 2026 · 10 min read
Why is a level base so important for a safe indoor padel court?
An uneven floor on an indoor padel court is dangerous. Find out which tolerances apply, which foundation type works best and who is responsible.
In this article
- What are the consequences of an uneven floor on a padel court?
- Which tolerances apply to the levelness of a padel court?
- Which foundation type gives the best levelness for an indoor padel court?
- How is the levelness of a padel court checked and certified?
- Can an existing uneven base be repaired?
- Who is responsible for a level base: the builder or the client?
- How I-Padel helps with a level and safe base
- Frequently asked questions
An uneven floor is one of the most underestimated risk factors on an indoor padel court. A floor that is not level directly causes unpredictable ball bounce, a tripping hazard for players and extra load on the steel structure. For any entrepreneur or club building a padel court, the levelness of the base is therefore not a detail but a basic requirement. In this article we answer the most frequently asked questions about levelness, tolerances, foundation choice and responsibility.
What are the consequences of an uneven floor on a padel court?
An uneven floor on a padel court has three direct consequences: unsafe playing conditions, uneven wear of the artificial turf and extra mechanical stress on the steel structure. Players can trip over unexpected differences in level, and a ball that bounces unpredictably disrupts the game and increases the risk of injury.
Besides the safety risks, an uneven base also has practical consequences for the service life of the court. The artificial turf does not lie evenly and wears faster on the high points. The cage structure, which rests on the foundation, can end up out of true if the base is uneven. This increases the forces on the connection points and accelerates fatigue of the steel. In the longer term this can lead to damage that is costly to repair.
Indoor locations have an additional problem: existing floors in sports halls or industrial halls have not always been built to the tolerances that padel requires. A floor that is adequate for logistics or basketball does not necessarily meet the requirements for a professional padel court.
Which tolerances apply to the levelness of a padel court?
As a general guideline, padel courts have a maximum flatness tolerance of 3 millimetres measured over a 3-metre straightedge. This means the difference in height over a distance of 3 metres may never exceed 3 mm. This is also the standard used in professional inspection by Kiwa ISA Sport.
This tolerance sounds strict, and it is. By comparison, an ordinary industrial floor is often built to tolerances of 5 to 10 mm over the same distance. An existing hall therefore does not automatically meet the padel-specific requirements, even if the floor looks level to the eye.
The reason for this strict standard is ball bounce. Padel is played at a relatively low level, with the ball being hit immediately after it bounces. A deviation of just a few millimetres is already noticeable to a player and directly affects playing quality. For official matches, an approved floor is therefore mandatory.
Which foundation type gives the best levelness for an indoor padel court?
For an indoor padel court, Supersub generally offers the best levelness. Supersub is a foundation solution based on foam concrete, a light, self-levelling type of concrete that naturally forms an extremely flat surface. It is precisely this self-levelling property that makes it particularly suitable for applications where levelness is crucial.
Supersub is used in both new builds and renovations, for example when converting a tennis court into a padel court. The thickness varies: about 10 cm is usual for renovation and about 15 cm for new construction. The exact thickness is always determined on the basis of soil conditions and the specific requirements of the project.
Drainage concrete is another widely used option, especially for outdoor courts. Drainage concrete is a water-permeable type of concrete with an open structure. It also produces a very flat surface and has a high load-bearing capacity, but it is less self-levelling than Supersub. For indoor use, where water drainage is less relevant, Supersub is in most cases the better choice because of the accuracy of the finished surface.
ZOAB asphalt, a porous asphalt variant, is used less often for padel courts but can be a suitable option in specific situations. Choosing the right foundation type always depends on the location, the use and the soil conditions. A preliminary site check and soil probing are indispensable for this.
How is the levelness of a padel court checked and certified?
The levelness of a padel court is checked with a precision straightedge or a digital flatness gauge that is moved across the entire playing surface. What is measured is the maximum difference in height over a distance of 3 metres. For official matches, inspection by Kiwa ISA Sport is mandatory, and levelness is one of the assessment criteria.
Kiwa ISA Sport is the recognised inspection body for sports floors and padel courts in the Netherlands. All foundation components used for padel courts must be certified by Kiwa ISA Sport. This applies to the material itself, but also to the installation. A court that does not meet the levelness standard fails the inspection and may not be used for official matches.
In practice, the levelness measurement takes place after the foundation has been poured and has cured, before the artificial turf is laid. Any deviations can still be corrected at that point. Once the artificial turf has been laid, repair is considerably more laborious and costly.
Can an existing uneven base be repaired?
Yes, an existing uneven base can be repaired in most cases, but the approach depends heavily on the nature and extent of the unevenness. Small local deviations can be corrected with a levelling layer. Larger structural problems, such as subsidence or tilting caused by poor soil conditions, require a more drastic approach.
When converting an existing tennis court into a padel court, the existing base is first assessed for suitability. If the substructure is stable and the unevenness is limited, Supersub can be used as a levelling top layer of about 10 cm. The material fills in irregularities and forms a new level surface without the need to remove the entire existing foundation.
If the base is structurally unsuitable, due to poor soil conditions, subsidence or a substructure with insufficient load-bearing capacity, then complete replacement of the foundation is the only lasting solution. Probing the soil beforehand shows what is needed and prevents a repair solution from causing problems again in the short term.
Who is responsible for a level base: the builder or the client?
Responsibility for a level base lies with the party that builds the foundation. If a padel court builder handles the complete turnkey process, including the foundation, that builder also bears responsibility for meeting the levelness standards. In that case the client is not responsible for the technical execution.
If the court is placed on an existing floor that was built by the client or a third party, the situation is different. In that case it is essential that the floor is inspected beforehand for levelness and load-bearing capacity. If the existing floor does not comply and the court is placed on it without this being communicated, questions of liability may arise.
The practical lesson is therefore: always make written agreements about who is responsible for the condition of the base before the court is installed. With a turnkey order, where one party arranges everything from foundation to handover, responsibility is clearly assigned and there can be no discussion about who is liable if something turns out to be wrong afterwards.
How I-Padel helps with a level and safe base
We handle the entire process from foundation to handover, including the levelness check. That means you, as the client, do not have to check yourself whether the base meets the standards. We do that for you, based on years of experience with all common foundation types.
What we offer in concrete terms:
- A preliminary site check and soil probing to assess the soil conditions
- Advice on the right foundation type: Supersub, drainage concrete or ZOAB asphalt
- Construction of the foundation with certified materials that meet the Kiwa ISA Sport standards
- A levelness measurement after pouring, so that deviations are corrected before the artificial turf is laid
- Complete turnkey delivery: from groundwork to artificial turf, LED lighting and steel structure
Would you like to know what a complete indoor padel court costs, including the foundation? Take a look at our cost overview for indoor padel courts or get in touch for personal advice. We are happy to help you think it through, with no obligation.
Frequently asked questions
How long does it take to level an uneven floor before the padel court can be installed?
The lead time depends on the chosen solution and the extent of the unevenness. A levelling layer of Supersub is generally applied within one to two working days, but the material then needs a curing time of at least 28 days before the artificial turf can be laid. For larger structural repairs, such as completely replacing the foundation, you need to allow for a longer lead time. Build this generously into your project planning to avoid delays at handover.
Can I measure the levelness of my existing floor myself before I engage a padel court builder?
You can get a rough indication yourself with a long spirit level and a 3-metre straightedge: lay the straightedge on the floor and measure the maximum gap beneath it. Keep in mind, however, that a professional levelness measurement with a digital precision gauge is more accurate and is carried out across the entire playing surface.
For a reliable assessment that also stands up legally and technically, a professional site check by a certified party is always advisable. That way you know for certain whether your floor meets the 3 mm over 3 metres standard.
What happens if the levelness measurement after pouring the foundation shows a deviation?
If the measurement after pouring shows a deviation above the permitted tolerance of 3 mm over 3 metres, this can in most cases still be corrected with a thin levelling layer before the artificial turf is laid.
This is exactly why the levelness measurement takes place before the artificial turf is installed: repair at that point is relatively simple and cost-efficient. If you wait too long and the artificial turf has already been laid, correction is considerably more laborious and more expensive. A good padel court builder schedules the measurement as a mandatory intermediate step as standard.
Does the levelness standard of 3 mm over 3 metres also apply to recreational courts that are not used for official matches?
Technically, Kiwa ISA Sport inspection is only mandatory for courts used for official matches. For purely recreational courts there is no legal obligation to meet this standard. Even so, it is strongly advisable to apply the same levelness standard to recreational courts too, because the safety and wear risks of an uneven floor apply regardless of the purpose of use. In addition, certified levelness increases the value and rental potential of the court in the long term.
Which questions should I ask a padel court builder about the foundation before I sign a contract?
Ask at least the following: which foundation type is used and why, whether the materials used are Kiwa ISA Sport certified, who carries out the levelness measurement and when, and who is contractually responsible if the floor turns out not to meet the standard after handover. Also make sure the levelness standard of 3 mm over 3 metres is explicitly included in the contract as a handover requirement. A serious padel court builder will give clear, written answers to all of these questions.
Can an existing sports hall floor made of concrete or wood serve directly as the base for an indoor padel court?
That depends entirely on the current condition and levelness of the floor. A concrete sports hall floor built for basketball or volleyball often has tolerances of 5 to 10 mm over 3 metres, which does not meet the padel requirement of 3 mm.
A wooden sports floor is in most cases unsuitable as a direct base because of insufficient load-bearing capacity and sensitivity to moisture. Always have a professional site check carried out before assuming that an existing floor is suitable; this prevents costly modifications afterwards.
How do the soil conditions under a hall influence the choice of foundation type?
The soil conditions largely determine which foundation type is feasible and durable. On stable soil with good load-bearing capacity, Supersub is sufficient as a levelling layer. On soft or uneven soil, such as peat or made-up ground, additional ground improvement or a completely new foundation is necessary to prevent subsidence over time.
Probing the soil gives objective insight into the load-bearing capacity and composition, and is therefore the basis for every sound foundation choice. Never skip this step, even if the hall has been in use for years.
