What is drainage concrete and why is it suitable for outdoor padel courts?

Drainage concrete is a water-permeable concrete floor that drains rainwater straight through the foundation into the subsoil. For outdoor padel courts it is one of the most widely used foundation solutions, because the court remains quickly playable even after heavy rainfall. The open structure of the material prevents puddles, offers high stability and, with good maintenance, lasts 25 to 40 years on average.

But when do you choose drainage concrete, what are the advantages and disadvantages, and how does it compare with alternatives such as Supersub? In this article we explain it step by step, so you can make a well-founded choice for your project.

What is drainage concrete and how does it work?

Drainage concrete is a type of concrete with an open, porous structure, so that rainwater does not stay on the surface but drains straight through the foundation into the ground. Unlike traditional, dense concrete, drainage concrete has no closed matrix: the aggregates are composed in such a way that space remains for water to pass through. This makes it particularly suitable as a foundation for outdoor sports facilities.

For a padel court, drainage concrete is almost always combined with a steel-reinforced ring foundation. That ring foundation absorbs the forces from the steel structure and the glass walls, while the drainage concrete floor itself provides a stable, water-permeable base on which the artificial turf is laid. The exact build-up of the foundation is always determined on the basis of the ground conditions, the wind load at the location and the intensity of use of the court.

Why is drainage concrete suitable for outdoor padel courts?

Drainage concrete is suitable for outdoor padel courts because it combines three properties that outdoor courts need at the same time: fast water drainage, high bearing capacity and an extremely flat surface. A padel court must be quickly playable after a rain shower, the steel structure and glass walls together easily weigh close to five tonnes, and consistent ball bounce requires an even base.

On an outdoor padel court, puddles are not only annoying for players, but also harmful to the artificial turf and the foundation in the long term. Because drainage concrete drains rainwater directly, the subsurface stays dry and stable. That extends the lifespan of both the foundation and the artificial turf on top of it.

In addition, the porous structure of drainage concrete has a slight sound-absorbing effect. That is relevant when the court is close to homes, although the sound-dampening effect of the foundation alone is not sufficient to meet municipal noise standards. Additional measures are needed for that.

What are the advantages and disadvantages of drainage concrete?

Drainage concrete has clear advantages for outdoor padel courts, but also a number of limitations you need to know about beforehand. The key points are set out below.

Advantages of drainage concrete

• Extremely water-permeable: the court remains quickly playable even in intensive rainfall and puddles are prevented.
• High stability and bearing capacity: suitable for the heavy load of a padel structure, including steel structure and glass walls.
• Flat surface: important for consistent ball bounce and a professional playing experience.
• Long lifespan: 25 to 40 years on average with correct use and maintenance.
• Resistant to weather: frost, heat and intensive use hardly affect drainage concrete when it is correctly installed.
• Relatively low maintenance: repairs are easy to carry out and can be made locally.

Disadvantages of drainage concrete

• Location-dependent: the ground conditions determine how well drainage concrete works. If the subsoil absorbs water poorly, water can still accumulate.
• Higher construction costs than asphalt: drainage concrete requires more material and craftsmanship than a standard asphalt layer.
• Not suitable for all soils: in clay-rich or poorly permeable soils, an additional drainage system or a different foundation solution is needed.
• Pores can clog: with little maintenance, fine particles can gradually close the open structure, reducing water permeability.

What is the difference between drainage concrete and Supersub?

The main difference between drainage concrete and Supersub is the material composition and the way water is drained. Drainage concrete is a porous concrete floor that lets water sink through the structure into the ground. Supersub is a foundation solution based on foam concrete: a light, self-levelling material that drains water through a different technical build-up.

Both solutions are water-permeable and suitable for outdoor padel courts, but they have different properties that make them more or less suitable in certain situations.

• Drainage concrete is heavier, has a higher bearing capacity and is particularly resistant to intensive use and heavy structures. It is a proven solution with a long track record in outdoor sports.
• Supersub is lighter, shock-absorbing and can even handle up to 500 mm of rainfall per hour. Thanks to its low weight, it can in many cases be poured within a single day, which shortens the installation time. The material is fully recyclable and requires less transport than traditional concrete.
• Thickness: Supersub is generally applied about 10 cm thick for renovations and about 15 cm for new builds. Drainage concrete has its own thickness recommendation based on the site conditions.
• Shock absorption: Supersub has a resilient build-up that reduces the load on joints and muscles. Drainage concrete does not offer this benefit to the same extent.

Which solution suits best depends on the ground conditions, the budget, the desired lifespan and the specific site requirements. There is no universal answer: good foundation advice always starts with a site check and cone penetration data.

When is drainage concrete the right choice for a padel court?

Drainage concrete is the right choice when the location has good ground conditions, the load from the structure is high and you opt for a proven, durable foundation solution with a long lifespan. It is particularly suitable for outdoor courts on open sites where water drainage is a priority.

Concrete situations in which drainage concrete is a good fit:

• Locations with a permeable subsoil (sand, gravel or well-drained ground).
• Projects where maximum stability and bearing capacity are required, for example with several courts side by side.
• Locations where the court is used intensively and the foundation has to last for years without major maintenance.
• Situations in which the client opts for a traditional, well-documented foundation solution.

Drainage concrete is less suitable for soils that absorb water poorly, such as heavy clay. In that case, water can accumulate beneath the foundation layer instead of sinking away. A soil investigation beforehand is therefore no unnecessary luxury: it prevents problems that are much more expensive to solve later.

What does a drainage concrete foundation for a padel court cost?

The cost of a drainage concrete foundation for a padel court is strongly location-dependent and cannot be viewed separately from the overall foundation project. As an indication, foundation costs for an outdoor padel court average between €20,000 and €40,000, depending on ground conditions, accessibility and the civil engineering work required.

A complete outdoor padel court including foundation starts at around €50,000 on average. The foundation is therefore the biggest cost factor for outdoor courts. That is also why we always draw up a custom quotation for outdoor projects: naming a fixed price without knowing the location is not honest and leads to surprises afterwards.

Factors that influence foundation costs:

• Ground conditions: a poor subsoil requires more preparatory work, such as excavation or additional drainage.
• Accessibility: hard-to-reach locations increase logistics costs.
• Size of the project: with several courts, economies of scale arise in materials and execution.
• Existing substructure: when converting a tennis court, part of the existing substructure can sometimes be reused, which saves costs.

It is tempting to go for the cheapest provider, but with the foundation you pay in the long term for the choices you make now. A foundation that causes problems after five years ends up costing far more than a slightly higher investment up front.

Does drainage concrete for padel courts have to be approved in the Netherlands?

Yes. In the Netherlands, all foundation components for padel courts must be approved by Kiwa ISA Sport. This also applies to drainage concrete. Only certified materials may be used if you want the padel court to be approved for official competition use under the KNLTB. If you use non-certified materials, you risk the court not being approved, with all the consequences that entails.

Kiwa ISA Sport is the recognised certification body for sports infrastructure in the Netherlands. After the court is completed, it carries out the inspection on the basis of the NOC*NSF guidelines for artificial turf sports surfaces. These guidelines prescribe that the artificial turf must lie on a certified, bound foundation. Drainage concrete falls under those bound foundations, provided it meets the stated requirements.

For many clients this is a point they underestimate. They choose a foundation supplier on price, without checking whether the materials are approved for sports use. That can mean that the court cannot be inspected after completion, which makes competition use impossible. Always work with a party that demonstrably works with certified materials and is up to date with the current inspection requirements.

At I-Padel we work exclusively with certified foundation materials that meet the Kiwa ISA Sport requirements. That way you can be sure the court can be inspected without problems after completion. Want to know which foundation solution best suits your location? Get in touch for an initial discussion, we are happy to think along with you, without obligation.

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