Sports fields are usually planned by landscape architects and laid out and maintained by specialist companies in gardening, landscaping and sports field construction. The choice of the right surface depends on the intended use. Natural and artificial turf, threshing floor and synthetic surfaces are most commonly used.
This bauwion knowledge page deals with the common surfaces for sports fields in outdoor facilities. When planning, the respective requirements of the sport and the playing characteristics of the surface must be taken into account. DIN 18035 contains technical specifications and also information on which sports surface is suitable for which sport or for multifunctional use. As with all floor coverings, care must be taken to ensure that the substructure is professional. The Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e.V. (FLL) publishes the "Guidelines for the Maintenance and Use of Outdoor Sports Facilities, Planning Principles". These apply to the inspection, care, maintenance and repair of outdoor sports areas that have been built in accordance with the requirements of DIN 18035.
, material and construction: Use determines the type of stress and thus determines the properties of the material to be used. When choosing the material, the builder/operator should be informed by the planner/contractor about the advantages and disadvantages of possible design variants, if necessary. In addition to the future maintenance costs, this also includes all possibilities for reworking or repairing the surface during the renovation of the sports field. The respective manufacturers should be involved in the consultation, as the different systems can vary greatly.
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natural turf:
Subsoil: Preferably in the form of a gable roof slope of > 0.5% and < 1.0%.
Turf base layer: A turf base layer is made up of several building material components, such as soil, sand and rock mixtures. Additives are used to store water. These water storage materials should have the highest possible organic matter content. As a rule, peat is used for this purpose, about half of which is supplemented by suitable composts or bark humus, and can be completely replaced by these substances if the product quality is of the best product quality. The main component of a permeable turf base layer is sand. In the case of soils that are too loamy, sand is added as needed to achieve the desired grain size distribution. The turf base course has a standard thickness of about 80 to 120 mm when compacted.
Drainage layer: If the groundwater level is high, groundwater regulation by drainage may also be necessary so that the water level does not rise higher than 0.5 m below the surface of the sports field. In the case of insufficiently permeable or poorly workable soils, drainage lines are installed, for example, at regular intervals of 4 to 6 m, with a collector connection. On workable soils with insufficient permeability, a system of drainage strings and drainage slots is used, which are filled with gravel or grain-stable chippings 2/8 mm to 30 mm above subgrade height. In locations with insufficient soil permeability, especially with difficult, water-sensitive, poorly stable or difficult-to-work soils, areas with very high precipitation and valley locations with a risk of flooding and backwater, drainage lines are installed at intervals of 5 to 8 m with a collective connection and a sand-rich drainage layer with a compacted layer thickness of 120 - 150 mm
is applied.Lawn cover: The lawn cover can be sown or laid as rolled turf. For sowing, a standard seed mixture (RSM) for sports turf should be chosen. The composition of the mixture, the minimum suitability of the grass varieties, the trade requirements for the seed and the amount of seed per m² can be found in the current status of the standard seed mixtures (RSM). Deviating seed mixtures can be used for special requirements, but legal requirements for the seeds remain unaffected. Grasses and herbs present before sowing must be largely removed. Favourable sowing times are from mid-April to the end of September, although climatic deviations are possible. The seed must be worked into the turf base layer as flat as possible to a maximum depth of 20 mm and pressed down. The commissioning of the lawn can begin as soon as the turf cover is closed and the lawn is resilient. This is the case at the earliest 1 month after acceptance, competitive matches should take place at the earliest 2 months after acceptance.
Turf should also be produced using grasses and varieties according to a rule-seed mixture (RSM) for sports turf. The felt thickness must not exceed 5 mm, the lawn must be healthy and firmly cohesive when it is laid. The peel thickness must not exceed 20 mm. For special requirements, ready-made turf with a larger peeling thickness or washed-out, soil-free finished turf may also be used. The turf must be peeled in uniform widths and thicknesses. The transport must be carried out without damage, in particular overheating, taking into account temperature, transport time and type of loading. Before laying, additional nutrient enrichment of the subgrade should be carried out with a phosphorus-accentuated lawn fertiliser. The laying of the finished turf is to be carried out on the damp and then roughened subgrade of the turf base course, closely adjoining each other and staggered. After laying, the turf must be pressed down by rollers, for example, and watered with 10 – 15 l/m². Turf is already fully resilient after 3-5 weeks and can also be laid in late autumn without any problems.
Artificial turf:
Planum: The gradient should be 0.8% so that if the subsoil is not sufficiently permeable to water, the seeping water can be quickly diverted to the drainage lines.
Construction method 1 - filled artificial turf surface on bonded elastic base course: The base course without binder is applied to the ground surface. This must absorb the seeping rainwater and direct it into the subsoil or drainage system. The minimum thickness is 200 mm. The water permeability kf should be at least 0.02 cm/s. Natural aggregates with a grain size of 0/32 mm or 0/45 mm can be considered as materials. When paving the base course without binders, the requirements of DIN 18035-7 Table 2 must be complied with. All mineral, natural building materials that meet the quality requirements in road construction are also permitted.
Bonded elastic base course: It consists of elastomer granules, e.g. rubber granules and elastic binder, e.g. polyurethane (PUR), as well as natural mineral aggregates. The nominal thickness must be 35 mm with limit dimensions of about 10 mm. The average value of all measuring points must be at least 35 mm. The bonded elastic base course is installed on a base course without binder and replaces the asphalt base course and the elastic layer.
Artificial turf: It is usually laid in 4 to 5 m wide strips perpendicular to the longitudinal axis of the pitch, whereby part of the marking lines can already be stepped in. The web connection is usually carried out using the bonding process. The width of the seam securing straps should not be less than 30 cm. The distance between the strips must not be more than one tuft lane width. The strips must lie firmly in the glue bed, whereby the glue must not rise into the pile. The lanes must not lie on top of each other at the joints. Before pole filling, the seams must be checked for their force-fit connection. In the case of pile-filled pavements, sanding may only be carried out in dry weather and dry pavement. After sanding has been completed, the uniform filling level must be checked, and then, if planned, the granules can be filled in the intended quantity. After approx. 4 weeks, re-sanding must be carried out to the final fill level.
Construction method 2, filled artificial turf surface, elastic layer on base layer without binder and additional levelling layer: If an elastic layer is laid directly on the base course without binder, this must be produced with an additional levelling layer. In this case, the thickness of the base course can be reduced to 150 mm. Instead of the bonded elastic base layer, elastic layers made of elastomer granules, e.g. rubber granules and elastic binders (e.g. PUR) can be used. In principle, they must be manufactured in a water-permeable design. The levelling layer must meet the following requirements:
Installation must be carried out with the optimum water content of the material of the levelling layer.
Construction method 3, unfilled artificial turf surface with elastic layer on asphalt base course: This construction method is mainly used for a combined use for hockey and football. In contrast to construction method 2, an asphalt base course is integrated between the elastic layer and the base course without binders. The layer thickness of the elastic layer produced in the on-site installation must correspond to at least 15 mm of the required minimum thickness, depending on the sport-specific requirements. The asphalt base course is predominantly single-layer with a layer thickness of at least 50 mm, grain size 2/11 and a water permeability of > 2 x 10-2 cm/s.
Fillers: Pile-filled systems require quartz sand to weigh down the synthetic turf, the amount is approx. 20 to 35 kg/m². The material contains quartz sand, rounded edges, silicon dioxide (SiO2) content > 96%, grain size 0.25 - 1.25 mm. Subsequently, granule interspersion can be made to improve the playing characteristics. Artificial turf granules must be abrasion-resistant, age-resistant, weather-resistant, elastic and environmentally friendly. They must not stain and must meet the requirements for fire behaviour, and material compatibility must be guaranteed between fibres and filler. Different bulk densities are determined by the specific density, shape and grain size distribution of the litter granules. Low bulk densities result in a higher bedding height than higher bulk densities. The following granules are currently available:
Cork is an ecological and economical alternative to recycled granules and especially to virgin rubber granules.
Hybrid turf:
Turf base layer: Hybrid turf hardly differs from natural turf in terms of soil structure. Unlike natural turf, long fibres of polyethylene are added to the turf base layer. This is why it is called a hybrid base course. The plastic fibers can be both rigid and elastic. In this method, the turf base layer must be removed to a depth of approx. 10 cm and then reinstalled.
In another process, woven plastic mats are incorporated and filled with the material of the turf base layer. The turf is then sown and the sports field can be used a few weeks later.
Another variant is implanted plastic fibers. In some Bundesliga stadiums and in stadiums of the English Premier League, sports turf systems are used, in which the natural turf is reinforced by implanted synthetic fibres. The fibers are implanted with computer-controlled machines 18 cm deep and 2 cm above the surface in a grid of +/- 2 × 2 cm. These make the sports turf more robust and resistant.
Plastic covering:
Base course without binder: This has the task of ensuring the load-bearing capacity for the layers above. Depending on the construction method, it must absorb the seeping rainwater and discharge it into the subsoil or drainage system. Even with the water-impermeable construction method, surface water that may penetrate (e.g. via joints or damage caused by spikes) must be passed on via the water-permeable base surface, the asphalt base course and the base course without binder and fed into the drainage system. The minimum thickness is 200 mm. The water permeability is said to be ≥ 0.02 cm/s. Natural aggregates with a grain size of 0/32 or 0/45 mm can be considered as materials. When paving the base course without binders, the requirements of DIN 18035-6 Table 2 must be met. All mineral building materials that meet the quality requirements in road construction are also permitted. In order to avoid grain transfers, the base course material must be paved in an earth-moist state (optimal water content).
Asphalt base course: It is designed in a water-permeable or water-impermeable construction method in one or two layers and consists of mineral aggregates and bituminous binders. The thickness of the lower asphalt base course is 40 mm, that of the upper asphalt base course is 25 mm. The water permeability is < 0.01 cm/s. The asphalt base course will be constructed with a maximum gradient of 1%, unless lower gradients are required from a sporting functional point of view. In the case of a single-layer construction method, the layer thickness of the asphalt base course with a grain size of 2/8 must be at least 50 mm. When paving the asphalt base courses, the requirements of DIN 18035-6 Table 3 must be met with regard to binder, grain size, minimum thickness, degree of compaction, water permeability, gradient, altitude, edge edging and flatness.
Plastic surface: The plastic surface is the top layer of the plastic surface. From a sports functional, protective and technical point of view, it must meet the requirements of DIN 18035-6 Table 4. It is designed in one or more layers in a water-impermeable or water-permeable construction.
Clay surfaces:
Earth level: The earth surface must have a sufficient load-bearing capacity, which is determined by a driving test in accordance with DIN 18035-5. In the case of playing fields, a gable roof slope should be created as far as possible, the slope distance must not exceed 40 m.
Unbound base course: When paving the base course, the ground surface must not be impaired in terms of height and evenness. The base course must be paved with a uniform minimum thickness of 150 mm. Suitable are, for example, lava, gravel or gravel base layers with grain sizes of 0/32 mm or 0/45 mm. The building material must be composed in such a way that it can be compacted and the requirements for flatness and nominal height can be met. The proportion of blown-off components, with a grain size < 0.063 mm, must not exceed 7% by weight when installed. The base course material must be paved at optimum water content in order to avoid segregation. The deviations from flatness may have a gap width of no more than 10 mm in tests under a 4 m guideline batten. The gradient corresponds to the slope of the ground and should not exceed 0.8% in the case of large playing fields. The unbound base course can be dispensed with if the subsoil meets the requirements of the base course.
Dynamic layer: The dynamic layer must consist of a grain-graded building material and be as porous as possible to ensure water storage. The grain line must lie within the grain distribution range of DIN 18035-5. The building material must interlock well to ensure the cohesion of the grain mixture and the shear strength. Suitable building materials are, for example, lava, tailings pile material or chippings mixtures whose composition lies in a grain distribution range between 0.063 mm and 16 mm, whereby the silt content < 0.063 mm must be less than 7% of the mass fraction in the installed state. The required water permeability must comply with DIN 18035-5. In a construction method without a base course, the dynamic layer takes over the function of the unbound base course. In this case, a layer thickness of at least 100 mm must be provided, depending on the subsoil conditions. Otherwise, a layer thickness of at least 60 mm is required after compaction. The dynamic layer must be applied without affecting the base course or the subsoil. Care must be taken to ensure that no assemblies of coarse-grained components form that allow the clay flooring building material to trickle in. Therefore, the dynamic layer must be applied in an earth-moist state and compacted with a suitable static roller. The use of vibratory plates is not recommended. This can prevent segregation, grain fragmentation or excessive compaction on the surface. After compaction, the dynamic layer must have a grade that does not deviate more than approx. 10 mm from the prescribed nominal height on its surface and has sufficient flatness. Pitch dimensions can be found in DIN 18035-5 Table 1.
Clay surface: A clay surface must be water-permeable and have a surface shear strength adapted to the intended sports operation. It consists of ground clinker with a grain size of 0/3 mm. DIN 18035-5 contains recommendations for the grain composition of large playing fields and athletics facilities. The material should comply with the RAL quality regulations. When paving the pavement, the properties of the dynamic layer and the base course must not be changed. The layer thickness of the pavement depends on the respective use and has a minimum thickness of 4 cm in the compacted state. Corresponding information is also contained here in DIN 18035-5, Table 4. The building material must be applied to the dynamic layer in an earth-moist state and statically compacted. There must be no grain shattering that would be significantly detrimental to water permeability. The grade of the clay surface must not deviate from the nominal height by more than about 10 mm at any point. The flatness of the finished surface of the clay flooring must meet the same requirements as for the dynamic layer. Use of the pavement is only permitted in an earth-damp state, in the event of waterlogging or during the freeze-thaw phase, use is excluded. It can take up to a year before a clay surface can be used as intended after installation.
Sand sports surfaces:
Subsoil: In the case of water-permeable soils, a floor trough of 35 - 45 cm depth is created in the area required for the playing field and a layer for drainage is dispensed with. In the case of water-impermeable soils, the floor trough for the additional drainage layer should be built 10 - 30 cm lower, in conjunction with longitudinal drain pipes at intervals of 5 - 6.5 m, which are connected to a receiving water or a seepage shaft.
Base course: Usually gravel, grain size 0/32 mm, thickness 150 - 300 mm, with a filter fleece cover.
Drainage layer: If drainage is required due to limited water permeability of the subsoil, various design variants are possible:
Sand layer: Quartz sand with a grain size of 0.063/2 mm, with rounded grain. The sand layer should be 400 mm deep on average, at least 450 mm in the middle area under the net, and at least 350 mm in the edge area. The transition between the playing field and the grown ground should be provided with a boundary of the playing field.
DIN 18035-1 Sports Fields - Part 1: Outdoor Facilities for Games and Athletics, Planning and Dimensions
DIN 18035-2 Sports Fields - Part 2: Irrigation
DIN 18035-3 Sports Fields - Part 3: Drainage
DIN 18035-4 Sports Fields - Part 4: Lawns
DIN 18035-5 Sports Fields - Part 5: Clay Surfaces
DIN 18035-6 Sports Fields - Part 6: Synthetic Surfaces
DIN 18035-7 Sports Fields - Part 7: Synthetic Turf Systems
Guidelines for the Care and Use of Outdoor Sports Facilities, Planning Principles" published by the Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e.V. (FLL)
"Sports Field Construction and Maintenance" Brochure of the German Football Association
"Planning and Construction of Beach Sports Facilities" published by the Federal Institute of Sports Science
Source: bauwion
