What is ZOAB asphalt and can it be used as a foundation for a padel court?

ZOAB asphalt is a porous type of asphalt that lets water through via an open structure. You probably know it from the motorway: it is the same material that dampens road noise and drains rainwater quickly. For padel courts it is less common than drainage concrete or Supersub, but in certain situations it can be a perfectly good choice as a base. In this article we explain what ZOAB is exactly, when it is suitable as a padel foundation and how it compares with other foundation types.

What is ZOAB asphalt and how does it work?

ZOAB stands for Zeer Open Asfaltbeton (very open asphalt concrete). It is a type of asphalt with an open, porous structure through which water drains directly through the surfacing into the ground. Rainwater seeps away through the gaps in the material instead of running off across the surface. This makes ZOAB naturally water-permeable and quick to dry.

The material has been used on Dutch motorways for decades, where it serves two functions: it absorbs road noise and prevents aquaplaning because water drains away quickly. That combination of noise dampening and water permeability also makes it interesting for sports infrastructure. The open structure does have a downside, however: the material is slightly more vulnerable than dense asphalt and calls for a well-considered application, matched to the location and use.

Why is the foundation of a padel court so important?

The foundation determines the stability and lifespan of a padel court. Without a good base, there is a risk of subsidence, uneven settling and ultimately damage to the steel structure and the artificial turf. A padel court, including structure, glass and artificial turf, weighs a considerable amount; the foundation has to bear that load for years.

For an outdoor padel court, the foundation plays an even bigger role than for an indoor court. The base must withstand frost, heat, heavy rainfall and wind load on the steel structure. Soil conditions vary greatly per location: clay, sand and peat soils each call for a different approach. Foundation advice based on soil penetration tests is therefore not a luxury, but a necessary step before you drive a single post into the ground.

In addition, in the Netherlands all foundation components must be approved by Kiwa ISA Sport. Anyone who works with non-certified materials risks the court not being admitted for official competition use by the KNLTB. It pays to check beforehand whether the chosen foundation solution is on the sports products list.

Can ZOAB asphalt be used as a foundation for a padel court?

Yes, ZOAB asphalt can be used as a foundation for a padel court, but it is less common than drainage concrete or Supersub. In certain situations, particularly at locations with good soil conditions and an existing asphalt base, ZOAB is a realistic option. The water permeability and noise dampening are clear advantages. Even so, the choice always calls for a location-specific assessment.

ZOAB is not used as a standard solution in padel, but that does not make it unsuitable. The porous structure ensures fast water drainage, which is a great advantage for outdoor courts. The court remains playable quickly even after heavy rainfall and puddles are prevented. That matches the requirements set for an outdoor padel foundation.

That said, ZOAB requires extra attention in the structural build-up under higher loads, such as the point load of steel posts. Combining ZOAB with a ring foundation and steel reinforcement is then a commonly used approach to properly absorb the forces from the steel structure and wind load. Whether ZOAB is the right choice for your location always depends on the soil conditions, the intended use and the available budget.

What are the pros and cons of ZOAB as a padel foundation?

As a padel foundation, ZOAB offers a number of concrete advantages, but also some limitations you need to know about beforehand. The assessment depends heavily on the site conditions and the type of use.

Advantages of ZOAB

• Water-permeable: rainwater is drained directly through the porous structure, so the court dries quickly and stays playable.
• Sound-absorbing: the open structure dampens noise, which can be an advantage at locations near residential areas.
• Durable when used correctly: ZOAB withstands frost and heat and, with good maintenance, has a long lifespan.
• Applicable on an existing asphalt base: in some situations an existing surface can be reused or serve as a base, which saves costs.

Disadvantages of ZOAB

• Less common in padel: ZOAB is used less often than drainage concrete or Supersub, so fewer suppliers have experience with it.
• Prone to clogging: the open pores can clog up over time with leaves, sand and fine dust, which reduces water permeability.
• Requires a good underlying build-up: with point loads from steel posts, additional structural attention is needed.
• Not always certified for every application: always check whether the specific product meets the Kiwa ISA Sport requirements for padel sports floors.

What is the difference between ZOAB, drainage concrete and Supersub?

ZOAB, drainage concrete and Supersub are three different foundation types that each let water through, but are built up differently and have different properties. The main difference lies in the base material and the technical properties that follow from it.

ZOAB asphalt

ZOAB is a porous type of asphalt. Water flows through the gaps in the asphalt and seeps away into the ground. The material is relatively easy to process and has a good sound-absorbing effect. A disadvantage is that the pores can clog up with insufficient maintenance.

Drainage concrete

Drainage concrete is a water-permeable concrete floor with an open structure. Rainwater is drained directly through the foundation into the ground. Drainage concrete has high stability and load-bearing capacity, suitable for the heavy load of a steel structure with glass walls. The average lifespan is between 25 and 40 years with correct use and maintenance. For padel courts, drainage concrete is often combined with a ring foundation with steel reinforcement.

Supersub

Supersub is a foundation solution based on foam concrete. It is lighter than traditional concrete, self-levelling and shock-absorbing. The flatness that Supersub delivers is exceptionally good, which directly contributes to a consistent ball bounce. Supersub is also fully recyclable and requires less transport and raw materials than traditional foundations. The water-permeable variant is suitable for outdoor padel courts; the non-permeable variant is used for indoor courts.

In short: ZOAB and drainage concrete are asphalt and concrete variants with an open structure, while Supersub is based on foam concrete and offers additional properties in terms of shock absorption and flatness. Which solution fits best depends on the soil conditions, the intended use and the location-specific circumstances.

Which foundation is best for an outdoor padel court?

There is no universally best foundation for an outdoor padel court. The right choice depends on the soil conditions, the location, the budget and the desired lifespan. Even so, drainage concrete and Supersub are the most commonly used solutions for outdoor padel courts in the Netherlands, because both are water-permeable and withstand Dutch weather conditions well.

Drainage concrete is a proven solution with a long track record. The high stability and load-bearing capacity make it suitable for locations with intensive use and heavy structures. Supersub complements this with better shock absorption and an extremely flat surface, which contributes to playing comfort and a consistent ball bounce.

ZOAB asphalt is also a good option in specific situations, particularly when an asphalt base is already present or when sound dampening is extra important. On open sites or at locations with a high wind load, every foundation choice also requires a structural calculation, so that the steel structure is properly anchored and the wind forces are absorbed.

A practical point of attention: for outdoor courts with a ring foundation, the steel posts are anchored directly in concrete foundation pads. The sports floor, the part on which the game is played, is then built separately from the ring foundation. This gives more flexibility in the choice of foundation type for the playing area itself.

What must a padel foundation comply with according to Dutch standards?

A padel foundation in the Netherlands must meet the requirements of NOC*NSF and Kiwa ISA Sport. All foundation components used in a certified padel sports floor must be approved and appear on the sports products list. Without this certification, the court is not admitted for official competition use by the KNLTB.

In concrete terms, this means that the foundation and the artificial turf together form a sports floor that is assessed as a whole. The sports floor consists of the artificial turf, including infill material (the top layer), and the bound foundation underneath. Both layers are tested for sports-technical and material-technical properties, such as ball bounce, flatness and water permeability.

For new builds and renovations of padel courts from 2025, measurements must always be taken and reported in accordance with the applicable NOC*NSF manual. After delivery, an inspection takes place to check whether the sports floor meets the established standards. Only after a successful inspection does the court receive a certificate on the basis of which competition use is permitted.

In practical terms, this system protects clients from unintended non-conformity. Anyone who chooses a supplier that works with certified materials and is familiar with the Kiwa ISA Sport requirements avoids the court being rejected after delivery.

At I-Padel we work exclusively with certified materials and guide the entire process, from foundation advice through to delivery. Want to know more about the possibilities? Take a look at our information on padel court foundations and get in touch for a non-binding exploration — we are happy to think along with you.

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