The RootBox soil cell system combines several fields of expertise. Besides its GREEN- and GREY infrastructure functions, it also offers opportunities to optimise urban rainwater management; the BLUE infrastructure.

Road engineering specification

Load-bearing capacity* ;

RootBox HD > 450 kN/m2
RootBox MD > 340 kN/m2
RootBox LD > 260 kN/m2

Lids point load capacity** ; 700 kN/m2

No pavement lifting ; The soil volume in the system can decrease and increase independently of the construction. This prevents subsidence or lifting of the pavement.

* NEN-EN 17150:2019-A Evenly distributed load-controlled pressure test. Tested without soil filling in the system. (This test only represents the load-bearing capacity of the uprights (legs) not the lids. Tested on 100cm system height. )
** NEN-EN 17150:2019-B Tested with a point load (steel ring round 200mm) on the system, directly on the lid, at the centre of the maximum span line. (This test represents the strength of the lid, the span between the uprights.)

Tree growing conditions

• Tree root growth* ; smallest opening >30cm diameter
• Soil volume**; > 90%
• One soil volume of uniformly, lightly compacted soil***
• Applicable soil mixtures
– The construction imposes no restrictions on the soil mixture. Even if loamy or moist soil mixtures are used.
– The soil must be filled and compacted homogeneously throughout the system. (lightly compacted at 1- 1,5 MPa penetration resistance)

* Roots grow bigger and bigger. To avoid restricting thickness growth, all openings in the soil cell system should be large enough for the future roots.
** percentage of soil in the soil cell system, with penetration resistance between 1-1.5 MPa. Soil mass acting as 1 continuous soil mass, for good water and air retention.
*** The soil volume is acting as one continuous soil volume, the perfect conditions for an ideal and natural water- and air distribution throughout the entire treepit. No horizontal barriers and or no grouped small opening preventing the ideal soil conditions.

Water management specification

• Lids ; Water-permeable*

• Drought-resistant ; System has no direct draining effect on the soil inside the system. **

• Open airlayer ; Water flowing inside the system is spread naturally over the soil surface.

* water passing the permeable pavement can drain into the root zone. The prevents saturation of the road foundation.

** To ensure that irrigation water is not wasted, and stormwater is filtered by the soil(-biology), water should not drain away directly through the uprights or through the vertical walls around the system. For optimal conditions for tree growth and pollutant decomposition, water should only infiltrate and drain through the soil.

Underground infrastructure

Utility friendly (existing and new)
• System consisting of loose uprights, allowing easy integration of existing utilities.
• Integrating utilities (Maximum utility diameter)
• inside a cell 30 cm
• between the cells 30 cm
• diagonal 19 cm

Underground obstacles (e.g. unforeseen utilities )
• Adaptable on site in all variable heights without ancillary parts.
• Units can be used freestanding without loss of load capacity

Maintenance and repair.
In case of emergency or maintenance, the system can be opened at any location without damaging the systems integrity. (circular de- and re-assembly )

Design features

• Any height possible to optimise soil volume per m2.
• A linked system with a 40 x 40 cm grid is standard.
• In a curve; the RootBox can also be used as a single unit.
• The lid has various options for integrating inspection risers / aeration openings.
• Minimal road build-up possible due to high point load resistance of the system

Installation features

• Fast and easy installation. No extra tools or handling needed
• Decks can be placed after filling with soil. No cleaning of the frames needed
• Big openings, easy to fil in with soil mix and easy to compact by walking over

Sustainability

• Manufacturer reclaim warranty after end of life
• 100% mono plastics; No use of Composite materials
• Use of recycled material; 100% circularly recyclable
• Transport volume. Designed for reducing transport costs.
• Design life expectancy ; 50 years

Description

The RootBox is a modularly designed soil cell system. The components together form a structural matrix able to withstand forces during and after installation. The mono plastic components (not using composite materials) form a skeleton under the pavement with an empty space of about 95%.

Unobstructed space for tree roots
The open space inside, once filled with specific tree substrate, provides unobstructed space for tree roots and/or to store, filter or retain rainwater. Natural and unimpeded root growth is possible due to optimal water and air management, which is ensured by having the smallest root opening larger than the required 30 cm diameter.
Also, the absence of horizontal bars allows homogeneous filling of the system, creating ideal conditions for air and water management and thus root development and stormwater management. These features also make it possible to integrate existing and new utilities into the system.

Flexible in height and loadcapacity.
The standard height of the system is 100 cm, but all other heights between 40 and 150 cm are also available and or customisable on site at any size. Due to the high structural load-bearing capacity, these modules are suitable for installation under driveable pavements. During installation and when using un-bonded road foundations on top of soil cells, the point load resistance in the middle of a lid is extremely important. The lid of the RootBox acts as bridges between the uprights achieving an extra high point load.

RootBox maintenance free stormwatermanagement system
For climate adaptive cities we need big trees. Large trees have large roots. The RootBox offers enough unobstructed soil volume underneath roads, thereby preventing roots from damaging the pavement. The soil inside the RootBox is acting like a sponge but not only capturing and infiltrating water but also breaking down pollutions. RootBox is the perfect way to grow big multifunctional urban trees.

Additional information

Dimensions	96 × 56 × 40-160 cm
Strength	260 kN/m2, 340 kN/m2, 450 kN/m2
Available std. heights	40 cm, 80 cm, 120 cm, other heights

RootBox-Brochure-EN

RootBoxHD Technical Datasheet EN

RootBox Installation Guidelines EN

RootBox Brochure NL

RootBox Technisch Fiche NL

RootBox Installatie Handleiding NL

RootBox Brochure DE

Is RootBox available throughout the world?

RootBox is designed to reduce transport costs, and meets all requirements all over the world. So Yes, RootBox is available and applicable all over the world, in hot and cold climat zones.

Can RootBox be used on existing trees?

Yes, RootBox can be used with existing trees. Because RootBox has fewer uprights compared to other systems, RootBox is easier to apply to existing trees. But let's be clear, using a root protection bridge is an easier system to apply between existing tree roots.

How to integrate stormwater in soil cell system?

Water can be diverted into the soil cell via various ways. E.g. via a street gully, via the open treepit. Important in this respect is that the soil does not remain saturated for too long. The standard is 48 hours which allows any tree species to survive. Of course, some tree species can survive much longer in saturated soil. For more information, please contact one of our specialists.

How big do roots grow?

Tree roots can grow really big. For urban trees the European standard specifies 30cm diameter as the maximum thickness.

What soil to use inside the soil cells?

Soil cells are made so that they can be filled with any soil. This means that you can use any soil suitable for your project in the soil cells without any problems. Soil specifications are not only tailored to tree requirements, but also depend on project goals, climate zone, availability of groundwater, etc. But also other factors such as durability, availability, the presence or absence of an irrigation system can be taken into account in determining the best soil for your project. Please feel free to ask one of our soil specilist to assist you on this topic.

Can soil cells be used with existing trees?

Yes, we can! While Soil cells are typically applied with new tree plantings, there are many circumstances where saving an existing tree is the goal. With the right preparations, care and consideration, Soil cells can be installed to provide the soil volume needed to support an existing tree. And if not possible consider the use of root protection bridges.

Description

Additional information

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