Designing an indoor school

A remarkable tool for work and comfort, an indoor school is an expensive piece of equipment. So it is important to distinguish between what is essential and what is not, because you can ride a horse without an indoor school if you have a well-designed, outdoor arena that can be used all year round.

The decision to build an indoor school must, therefore, be carefully considered. Generally speaking, it is in the interest of a riding school that is just starting out to first build a good outdoor arena (possibly lit, partially sheltered) before investing in an indoor school.

The classic dimensions are 20 m x 60 m (between the kickboards). Nevertheless, the ideal indoor school for building up the confidence of young riders, breaking in young horses, and showing horses which are free jumping should not exceed 20 m x 40 m, possibly 18 m x 36 m.

For ponies, a 15 m x 20 m indoor school is perfectly functional: the ponies thus remain permanently under the control of the instructor and the space is suitable for children. However, it is important to avoid going below 12 m x 24 m, as this dimension is suitable for only the smallest of ponies.

There must be a minimum of 4 m (or even 5 m) clear height for horses and 3.50 m for an indoor school reserved for ponies. Please ensure that the phenomenon of “crushing” is taken into account: the larger the indoor school, the higher the roof should be.

Safety regulations require the presence of two outward-opening doors. One of them must allow for lorries to enter with materials and machinery to maintain the indoor school footing (at least 4 m high and 3 m wide: ideally 4 m x 4 m). The other door, intended to allow mounted riders to enter, measures 2 m x 3 m and, if possible, should be positioned, depending on the location of the stables, near a corner of the indoor school.

Kickboards are designed to keep the horses away from the walls, so that riders’ legs cannot be caught between the horse and the wall.
Typically, kickboards are 1.35 m to 1.50 m high (in relation to the finished footing), around 45 cm to 60 cm wide, and are slightly slanted, around 15°, with the bottom being the widest part.

Because an indoor school is normally equipped with a sprinkler system, the material used for the kickboards must be water-resistant: multi-ply plywood treated to resist humidity, rot-proof recycled plastic panels. Chipboard (even of CTBH quality) is to be avoided at all costs because it is not strong enough.

Suspended kickboards keep the lower part of the board away from the humidity of the footing and also make it easier for tools to be used to maintain the surface of the ring. However, these are not always suitable for small ponies.

Finally, the kickboards must not have any sharp corners, neither at the bottom nor at the top.

The quality of the footing essentially depends on the nature of the surface layer known as the “top layer”. However, the quality and frequency of maintenance is crucial to preserving the footing and optimising the technical solution that has been put in place. It is therefore crucial to provide adequate equipment, as well as to ensure that maintenance staff are competent.

Building principles

The following considerations must be taken into account

• The quality of the natural terrain: in order to determine whether it is necessary to build foundations.
• Any water inflows (ground water, run-off from outside), which will have to be channelled and evacuated.

Building takes place in several stages:

• Excavation of the natural ground;
• Creation of the supporting surface (shaped base - foundations) which supports all the loads and contributes to the quality of the whole;
• Installation of the top layer.

In any case it is desirable that:

• The level of the finished footing is altimetrically higher than the natural outdoor terrain (“buried” indoor schools should be avoided at all costs);
• The top layer should not slip on the foundations but should be firmly embedded into them.

Basic shape - foundations

After analysing the natural footing (physicochemical analysis - Proctor test), there are three possibilities:

• If the natural soil can be compacted: it can be used as a supporting footing directly for a top layer.
• If the natural soil can be treated with lime, cement, mixed: after treatment, it can be used as a supporting surface for a top layer.
• If the natural soil cannot be compacted or chemically treated: foundations must be laid.

Top layer

• “Noble” materials are the result of extensive experience or research aimed at improving load bearing capacity, comfort, durability and limiting water consumption. For example: washed industrial sands, fibrous sands, calibrated and dust-free softwood chips, stabilised wood aggregates, etc.
• Low-cost materials or industrial by-products. For example: non-industrial rounded sand, uncalibrated wood chips, leather shavings, tyre chips, shredded rubber from shoes, etc. The list cannot be exhaustive, it is often dependent on local opportunities, and it is not possible to present in detail the behaviour of all these materials, whose quality and supply vary greatly.

A few companies specialising in equestrian footings use quality products. Consult a range of professionals on the basis of a descriptive, quantitative and detailed estimate, in order to compare their services. Also ask for references from previous projects that allow you to get some feedback from other users.

Sand top layer

For reasons of durability and in view of maintenance or supply constraints, sand footings are the most widespread in indoor schools:

• Coarse crushed sand 0/4 mm, despite standardised production, is prohibited as it creates too hard a footing.
• Rounded sand 0/4 mm produces varying results depending on the nature of the supporting footing, the thickness used and above all the type of sand (friability, percentage of fine particles). They often give a footing that is described as “very deep”.
• Fine rounded sand can adequately meet expectations, but production is not standardised, resulting in great heterogeneity depending on the extraction sites and behave very differently according to the percentage of fine particles and water content.
• Very fine industrial rounded sand (companies specialising in equestrian footings) meets the requirements of flexibility and load bearing capacity. However, it can sometimes be judged to be a little firm and requires frequent watering. The limited number of extraction sites often leads to high transport costs.
• Fine rolled fibre-reinforced and reinforced sand. In order to slightly reduce water consumption and to increase the flexibility or cohesion of the footing, mixtures of sand and fibres or geotextile elements have been developed and appear to give satisfactory results.
• Pitch sand: this natural alluvial material, which is used near bays (Mont Saint-Michel, the Somme estuary, Bay of Saint-Brieuc) and is not transformed, is of inconsistent quality. It is suitable for show jumping indoor schools, but not for intense and repeated use. It is fairly difficult to maintain.

Rubber top layer

Compact vulcanised rubber chips are used in pony clubs in particular because they are flexible, easy to maintain, durable, cushion falls, do not require watering and are frost resistant. They are perfectly suitable for an introduction to horse riding, but not for sports or competition, as they provide a surface that shifts under the horses’ feet.

Maintenance

The texture of an equestrian footing changes according to two parameters: watering and mechanical maintenance.

With the exception of tyre chips and non-irrigated footing systems, all materials must be watered regularly to achieve good cohesion and/or limit dust formation. The installation of an integrated programmable watering system is therefore highly recommended.

Mechanical maintenance makes it possible both to restore the flatness of the footing and to manage its texture. The footing can then be compacted with a heavy bar or roller and decompressed using a tined tool.

The ability to collect droppings is the guarantee of the durability of an equestrian footing and is therefore indispensable.

The quality of the lighting is essential for riding, as well as for the safety and enjoyment of users. Good lighting should:

• Ensure sufficient and homogeneous lighting levels;
• Limit the risk of glare;
• Allow colours to be clearly visible (artificial lighting).

Water requirements

An indoor school footing must be kept damp as the surface tension of the water provides cohesion and limits dust. Sand (especially very fine sand) requires more watering.

Programmable automatic watering is one solution that combines comfort and performance. It is essential to entrust a specialist with the installation and configuration of this equipment.

Evaporation in an indoor school is limited, so the surface should be watered regularly but in small quantities. If the available water pressure is low and/or the area to be watered is large, it is possible to water over several different times.

Availability of water

It is essential to understand the hourly flow rate and dynamic pressure for any project. When setting up equipment purchased from a catalogue without a field visit, failures can often be explained by this criterion alone.

Choice of material

The cheapest solution for small areas only requires the installation of watering nozzles to which a beater sprinkler fed by a flexible hose, moved manually, is connected. This solution is labour-intensive and causes puddles at the sprinkler locations.

An intermediate solution is the use of a small self-propelled sprinkler on a hose. This solution requires very little manpower.

The most flexible formulas use fixed watering installations.

Installation of sprinklers

The general rule is that the distance between two sprinklers should not exceed 60% of the diameter of the sprinkler. Each appliance is supplied with a description in which the manufacturer indicates the maximum permissible distances. It is imperative to respect these recommendations, because the greater the overlap of the jets, the more uniform the watering.

Sprinkler systems

There are two ways to control the sprinklers:

• Manual systems: by 1/4 turn valve.
• Automatic programmable systems: the sprinklers are controlled by electric valves, which in turn are controlled by an electronic programmer. Once started, the watering programme runs automatically. This device is naturally a little more expensive than the manual system but it ensures a more even watering.