Landscape architects constantly face the challenge of balancing aesthetics with practicality, and that challenge is epitomised when it comes to turf. In busy periods, many businesses need to use over-flow car parks or temporary grass roads, often resulting in significant turf damage and hampering its ability to recover after heavy wear. However, such occurrences can become a thing of the past by taking inspiration from the world of sports surfaces.
Here, Tim Edwards, Technical Sales Manager at Tarmac’s Topscape team, explains more.
Given the high-impact nature of most grass-based sports, keeping the surface – be it a rugby pitch or a racetrack – as unaffected as possible is a high priority. One of the ways in which this is often achieved is through the use of a fibre-reinforced sand which is incorporated into the rootzone, before the pitch is seeded. The additional fibres enable the use of the appropriate sand grade to give a free-draining surface as well as the required stability, and generally prevent the surface from breaking up under the rigours of the sport in question.
However, what many may not be aware of is that the same principles of achieving stability through substrate reinforcement can be applied to the landscape architecture sector.
The root of the problem
Many existing landscaped areas currently do not feature modified rootzones or Loksand fibre-reinforcement. Given the trend in recent years of keeping paved areas to an absolute minimum – both from an aesthetic and sustainable water management perspective – high numbers of green spaces are now being used for different purposes, from overflow car parks and grass roads to music festivals and small runways. Worryingly, much of the turf – and importantly the rootzone underneath – is unable to cope with the sporadic yet intense demands placed on it. As such, it can quickly compact and lose structure, becoming both aesthetically unattractive and unsuitable for further use.
There are a number of reasons Loksand fibre-reinforced rootzone may not have been used by landscapers in the first instance, including lack of awareness, cost and ‘bedding in times’. However, many of these reasons are shrouded in uncertainty.
Whilst there is no overarching standard governing the construction of grass roads, there are a number of advisory documents that contractors can consult. Road Note 29 provides in-depth advice and guidance on grass road construction, depending on whether it is a high-volume but low-use road (such an overflow car park), low-volume but regular use road (such as a grass road regularly used by maintenance vehicles), or emergency access route (to allow a fire engine or ambulance close enough access to a building’s perimeter). The document also outlines how to determine the correct sub-base thickness for supporting the fibre-reinforced soil to ensure it can cope with the anticipated traffic loading. What’s more, there are some British Standards governing elements of the grass road construction process. For example, the British Standard for testing soils for civil engineering purposes (BS 1377:1990) details subgrade assessment criteria, and the British Standard for Topsoil (BS 3882:2015) also outlines requirements that need to be met regarding the soil’s ability to sustain grass growth.
Therefore, whilst there is not one overarching set of regulations contractors can consult, there are several working documents which can provide reliable guidance when it comes to the design and construction of grass roads. As such, I would urge landscapers not to be put off, especially given that many of the offerings currently available – including Loksand from Tarmac’s Topscape team – have been pioneered following years of experience supplying bespoke solutions for some of the country’s most prestigious sports facilities.
Need for a long-term landscaping solution
Loksand Fibre-reinforced sand for commercial landscaping projects works in much the same way as it would for a sports pitch. For the best and most time efficient results, the modified rootzone should be partnered with specially pre-grown Loksand turf. Using this turf ensures the fibre reinforcement of the rootzone extends all the way to the grass surface, offering a greater level of security and resilience compared to traditional turf. Furthermore, the use of pre-grown turf allows the contractor to complete the finished grass surface far quicker than producing it from seed.
Landscapers can also specify the volume of fibres used to reinforce the rootzone depending on the required application; for example, if the turf only needs to accommodate foot traffic, a low-volume Loksand fibre content solution would be required. If it is to be used as a car park where HGVs may be present, then a higher volume concentration of Loksand fibres would be more suitable.
As with any turfed amenity area, regardless of application, any Loksand installation should be supported by a suitable drainage system.
Understanding the issues
A fibre-reinforced sand can offer much-needed rootzone support to a number of different applications, including both new-build and renovation projects.
One sector which is particularly suited to the benefits on offer is heritage properties and stately homes. Here, aesthetics naturally form a significant part of the attraction and site managers are keen to keep large paved spaces to a minimum. As such, spare fields are often used as overflow car parks in peak season. These can quickly become churned up during intense periods of activity, particularly when combined with wet weather, and ultimately may become unusable. Similarly, machinery such as cherry pickers are often used to carry out routine maintenance or clean windows, yet given their heavy-duty nature, some sites are forced to either construct a paved area to facilitate the machinery or again suffer from a disturbed and damaged grass surface. In either instance, the aesthetics are compromised.
Both scenarios could easily be resolved through the installation of a Loksand fibre-reinforced rootzone, to deliver a much greater level of security and integrity within the turf, without detracting from the property’s looks.
Another typical scenario where a reinforced rootzone would significantly benefit the end user would be emergency access routes in communal sports pitches. If a serious accident were to befall a recreational rugby or football player, and it happened on a site with multiple pitches used by the public, an ambulance could have great difficulty driving across the pitches if they were waterlogged or of poor quality turf. A simple way of avoiding such a scenario would be to install a ‘green road’ whereby a dedicated turf route is dug up and then re-laid with fibre-reinforced rootzone, to provide reliable access to the pitch which can stand up to the rigours of emergency vehicles.
Ultimately, the benefits of employing a fibre-reinforced sand or rootzone go beyond applications such as stately homes and sports clubs, and can be extended to extreme heavy-duty environments such as grass runways and even music festival sites.
Ultimately, a key remit in any professional landscaping job is to deliver quality, pleasing aesthetics. Fibre-reinforced sand and rootzone gives landscapers the opportunity to enhance a project’s aesthetic attributes by negating the likelihood of severe turf damage and removing the need to resort to paved areas. It may be a relatively unfamiliar offering to the commercial landscape market, yet it provides a fantastic opportunity for the industry to capitalise on the research and development undertaken by the professional sports turf industry, which is now widely available in high volumes for commercial projects.
There will always remain areas where a road or paving will be the most effective solution, but fibre-reinforced rootzone gives landscapers a greener, and much more flexible choice for the middle ground going forward.