Grass Reinforcement Mats for Playgrounds – Safe Openwork Surface (HIC)
Grass Reinforcement Mats for Playgrounds with HIC and PZH Certification
Rubber grass reinforcement mats, also referred to as openwork mats or rubber grass grids, are a safe, biologically active surface that combines two key functions: fall protection in accordance with the HIC parameter and preservation of the natural appearance of the lawn. The open honeycomb structure allows grass to grow through freely and enables unobstructed water drainage, eliminating puddle formation and preventing surface subsidence during heavy rainfall. Safe openwork playground mats are used under swings, slides, and in recreational zones. They ensure ground stability and provide an anti-slip surface, reducing the risk of injuries and allowing year-round use.
Why are grass reinforcement mats a safe biologically active surface?
A safe biologically active surface is a semi-permeable surface that provides effective impact absorption, rainwater retention, and plant growth, including grass. Grass reinforcement mats are an example of this, as their openwork, perforated honeycomb structure allows grass and other vegetation to grow through the surface while preserving the natural function of the soil. The openings in the mats enable free drainage of rainwater, eliminating puddle formation and surface unevenness while supporting water retention in the subsoil. As a result, the ground remains stable and level, allowing year-round use of playgrounds and recreational areas. Additionally, the elastic material of the mats (SBR/EPDM rubber) effectively absorbs impacts, reducing the risk of falls and injuries, which makes grass reinforcement mats a safe and functional solution for children, parents, and landscape designers.
Key benefits of grass reinforcement mats in outdoor applications
High level of user safety
The honeycomb-structured mat creates an even and stable surface that prevents ground subsidence in areas of intensive use. The openings in the mat allow free water drainage, keeping the entire surface dry and anti-slip, which minimizes the risk of slipping, tripping, or falling. The elastic, shock-absorbing structure of the material increases the safety of both children and adults while maintaining the natural appearance of the lawn and the function of a biologically active surface.
Effective fall protection (HIC)
Grass reinforcement mats with HIC certification effectively reduce the risk of injuries during play. The HIC parameter (Head Injury Criterion) allows the surface thickness to be precisely matched to the height of playground equipment such as swings, slides, ladders, or climbing walls, ensuring controlled impact absorption. As a result, each play area meets applicable safety standards.
Natural lawn appearance
The open, perforated structure of the mat enables free grass growth, allowing the natural appearance of the lawn to be preserved. The surface combines aesthetic and practical functions by stabilizing the ground and creating an even play surface without irregularities, while maintaining a cohesive and visually attractive area. Openwork mats are ideally suited for public spaces, parks, gardens, playgrounds, and recreational zones, enabling designers to create safe and functional environments.
Subsoil stability and year-round use
The rubber grass grid limits the formation of ruts, subsidence, and localized surface irregularities. The openwork structure allows rainwater to drain freely into the ground, preventing the surface from becoming muddy and eliminating standing water. Safe openwork playground mats retain their functional properties regardless of the season, including during heavy rainfall and under low-temperature and frost conditions.
Easy and quick installation
Installation of honeycomb-type mats does not require a base layer or concrete screed. It is sufficient to level the ground and clear the substrate of roots, branches, and metal elements, which significantly reduces the scope of construction work and shortens project execution time. The modular design allows precise adaptation to the terrain shape. Individual mats are connected using cable ties and anchored to the ground with mounting pegs. This fixing method prevents mat displacement during use and ensures a stable, uniform surface. Properly installed rubber grass grids do not cause surface unevenness, deformation, or edge separation.
How to choose rubber grass reinforcement mats for a specific application?
The HIC (Head Injury Criterion) parameter defines the maximum height from which a child can fall onto the surface without the risk of serious head injuries. The table below presents the selection of grass reinforcement mat thickness in relation to the height of playground equipment, in accordance with the HIC certificate.
The selection of grass reinforcement mat thickness should always be adapted to the height of playground equipment and the intensity of use.
The Free Fall Height (FFH) of HIC-certified grass reinforcement mats with a thickness of 23 mm from Power Rubber is 3 m. The FFH depends on the type and degree of compaction/looseness of the subbase as well as its grain size.
How to install grass reinforcement mats on grass?
Proper installation of grass reinforcement mats, also referred to as rubber grass grids, ensures effective fall impact absorption (HIC) and an aesthetic, natural lawn appearance. Installation does not require a concrete subbase or the use of specialized tools.
How to install grass reinforcement mats on grass – step-by-step instructions
Preparation:
Mow the grass to a minimum height (approx. 2–3 cm). Remove stones, roots, branches, and metal elements. Level the ground (the grass reinforcement mat functions as a safe biologically active surface – a concrete screed is not required).
Placement:
Lay the openwork mats directly on the grass. If necessary, they can be cut with a utility knife. The mat should not create local unevenness (bulges or ridges).
Fixing:
Connect the mats using cable ties at 20 cm intervals and secure them to the ground with mounting pegs. Remember to use two cable ties in the corners, installed crosswise. After tightening, cut off the excess tie ends using scissors.
Filling (optional):
Fill the openings with fertile soil. For a faster “disappearing” effect of the grass reinforcement mat, grass seed can be sown in the filled areas. Water the surface carefully, avoiding washing the soil out of the openings.
After installation is complete, it is recommended to check the stability of the entire surface. Ensure that the rubber grass grid adheres evenly to the ground. The surface is ready for use. The full visual effect will be visible after several weeks, when the grass begins to grow through the openwork structure, creating an aesthetic, green, and at the same time safe biologically active surface.
Frequently Asked Questions (FAQ) – Openwork Mats
Will a lawn mower damage the grass reinforcement mat?
No, provided the grass is mowed to an appropriate height and the mat has properly integrated into the ground. A correctly installed openwork mat for a playground or garden is positioned below the mower blade cutting line. Grass grows through the openings of the mats, forming a natural protective layer.
Can wheelchairs and baby strollers be used on grass reinforcement mats?
Yes, grass reinforcement mats stabilize the ground and prevent wheels from sinking into mud or soft soil. A wheelchair or baby stroller can move smoothly and steadily across the surface without wheel blockage. It is also worth noting that honeycomb grass mats improve traction and evenly distribute the load over a larger surface area, preventing rut formation and eliminating bogging after rainfall.
Is an openwork playground mat frost-resistant?
Yes, openwork playground mats are frost-resistant. They are made of high-quality EPDM/SBR rubber designed for outdoor applications. The honeycomb-structured rubber mat retains its elasticity and functional properties at low temperatures, which means it does not crack during frost nor degrade due to precipitation or changing outdoor weather conditions. It does not absorb water and is resistant to aging caused by long-term UV exposure. It can be used year-round without the need for dismantling during the autumn–winter period.
Can grass reinforcement mats be installed without a concrete screed?
Yes, grass reinforcement mats are designed for installation directly on natural ground, without the need for a concrete subbase. It is sufficient to compact and level the soil and remove branches, roots, stones, and metal elements that could cause point loads, local unevenness, or surface bulging.
Does a rubber grass grid sink during rain and form puddles?
No, a properly installed rubber grass grid enables rapid drainage of rainwater into the subsoil, eliminating the risk of puddle formation and water stagnation. The openwork structure of the mat stabilizes the ground, limiting the formation of subsidence and surface unevenness. The mat demonstrates high resistance to adverse weather conditions, including heavy rainfall, temperature fluctuations, and frost, which allows it to retain its functional properties and be suitable for year-round use.
Do openwork mats meet safety standards for playgrounds?
Yes, grass reinforcement mats meet the requirements of the EU standard EN 1177, which defines the required surface thickness for a given material to effectively absorb impact energy and reduce the risk of serious head injuries. The key indicator is the HIC (Head Injury Criterion) parameter, which specifies the maximum fall height at which the surface provides effective protection.
Can rubber grass reinforcement mats be classified as biologically active surface (BAS)?
Grass reinforcement mats constitute a safe and biologically active surface in public spaces, playgrounds, parks, and private areas. They are classified as a biologically active surface (BAS), which contributes to meeting the requirements of building law and local guidelines of local spatial development plans (LSDP).
From a regulatory perspective, a biologically active surface is an area that enables natural plant vegetation and the retention of rainwater, while maintaining the ecological functions of the ground.
In Polish construction law and design practice, for grass reinforcement mats filled with fertile soil and sown with grass, it is standardly assumed that 50% of the surface can be classified as BAS. It is essential that the surface is installed on a permeable subbase that allows proper water drainage. Each time, it is recommended to verify compliance with the LSDP or Development Conditions (DC) in order to correctly calculate the biologically active surface for the entire area.
Certified grass reinforcement (openwork) mats for playgrounds can be purchased from Power Rubber.
Grass Reinforcement Mat Installations on Playgrounds – User Safety and Surface Aesthetics
