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Frequently Asked Questions for DuPont™ Plantex® GroundGrid®
Application
Installation
Filling Materials
Product in use

What are DuPont Weed Control Fabrics?
DuPont weed control fabrics are scientifically engineered non-woven fabrics manufactured in a unique patented process in which continuous filaments of polypropylene are spun into a multidirectional web that is thermally and mechanically bonded. This process results in a uniform product with superior strength and durability, and excellent properties for air and water permeability.

What are the benefits of using DuPont Weed Control Fabrics?
Excellent properties for permeability allow water, air and nutrients to pass through the fabrics, while helping to prevent most weeds from growing through. This helps to promote a soil environment conducive to healthier plant growth, while providing low maintenance weed control. DuPont weed control fabrics’ superior properties for strength and durability assure long-term performance and satisfaction.

I see some weeds growing in Plantex® tooped areas. How is this possible?
Over time all types of top covering will fill up with an organic layer which facilitates growing of airborne seeds. However these seeds cannot get their roots down through Plantex® Premium or Plantex® Pro into the soil, so their removal is very easy. To reduce the possibility for airborne weeds, you should:
1) chose right from the beginning a good quality mulch (e.g. bark) or an non-organic top cover (e.g. gravel)
2) do not overdo the thickness of the mulch layer, to allow it drying out during the warm days. Mulch decomposition is faster when always wet.

Will DuPont Weed ControlFabrics prevent all weed growth?
DuPont Weed control fabrics are effective against most weeds. Only difficult-to-control perennial weeds such as couch grass and horsetail may require additional measures. In the case of couch grass, a doubling up of the mulch layers should reduce most instances (e.g. 10 cm). For horsetail we recommend either a hand full of lime placed around the infected area and then lay a double thickness of Plantex® Premium or Plantex® Pro before finally covering with a double layer of mulch or use DuPont™ Plantex® Gold with a layer of mulch. Furthermore, weed seed germination in any mulch on top of the fabric is not prevented.
These recommendations are based on past experience but do not imply any warranty for future installations.

Can herbicides be used with the fabric?
Yes. The use of an herbicide may be desired for improved performance under difficult-to-control weed conditions or for weeds that have germinated in the mulch on top of the fabric. Be sure to consult and thoroughly read the herbicide manufacturer’s product label for recommended and approved uses.

How long will DuPont Weed Control Fabrics last?
DuPont weed control fabrics are UV stabilized and, in the absence of direct sunlight, will last many years. As long as Plantex® Premium or Plantex® Pro has been laid correctly with the correct depth of mulch covering, it will last for 20 years (Plantex® Premium), for 25 years (Plantex® Pro). If used uncovered, or with insufficient cover, the ultra violet rays in sunlight will, over time, reduce its tensile strength. Plantex® Gold is guaranteed 25 years if covered correctly.

Water appears to run off the fabric. Is the fabric really permeable to water?
Absolutely! The fabric must be "wetted-in" to overcome water surface tension. Once the fabric has been covered with a top-dress mulch, the fabric will readily "wet-in" and allow water passage.

Can I fertilize my plants through the fabric?
Yes. Any liquid or water-soluble fertilizer will readily pass through and will not adversely affect the fabric.

Are DuPont Weed Control Fabrics safe to use around water and/or a fish pond?
Yes. DuPont Weed Control Fabrics are inert and will not contaminate the water or harm fish. Plantex® can even be used to plant pond baskets and act as a filter layer in fish tanks.

Are DuPont Weed Control Fabrics harmful to children or pets?
No. DuPont weed control fabrics are inert and will not cause adverse affects to children or pets. Be sure, however, to dispose of product packaging, particularly plastic wrapping, to prevent possible suffocation or ingestion by children or pets.

Which way up do I lay DuPont Weed control fabric?
Any way! Plantex® Premium, Plantex® Pro and Plantex® Gold can be laid with either side facing the soil. For vertical applications e.g. preventing weed invasion from a neighbouring property, DuPont™ Plantex® RootBarrier should be considered.

Can I lay DuPont weed control fabrics around existing beds?
Yes, although slightly more fiddly than a new bed, DuPont weed control fabrics can be cut around the base of your plants. Remember to allow a 10 cm overlap, when laying more than one piece.

How much overlap is required between overlapping lengths of fabric?
In general, 10 cm is sufficient.

What type of top-dress mulch is recommended?
Any type of organic (wood) or inorganic (stone or rubber) mulch may be used. For long-term durability and performance 5 cm of mulch is recommended. The mulch layer should be of good quality, dry and not too thick. A thick mulch will not dry out and will decompose faster, resulting in humus substrate for air-borne seeds.

Can I use DuPont Weed Control Fabrics without mulch?
DuPont™ Plantex® Gold and DuPont™ Plantex® CocoMat can be used without being covered by any type of mulch. Plantex® Pro weed control fabric must be covered to guarantee durability.The DuPont™ Plantex® product range offers four weed control fabrics: DuPont™ Plantex® Premium, Plantex® Pro, Plantex® Gold and Plantex® CocoMat

Can I walk on DuPont™ Plantex® Premium or Plantex® Pro?
Yes, but the soil must be firm enough to support you. Otherwise Plantex® Premium and Plantex® Pro may get folds and any overlaps may be reduced or even torn up.
Be aware when walking on Plantex® that it is more slippery than natural soil.

Can I walk or drive on pavement that was underlined with Plantex® Premium or Plantex® Pro?
Plantex® Premium and Plantex® Pro are used under footpaths in public parks, pedestrianised and landscaped areas, under golf bunkers, turfed sports surfaces and many other applications.
However, for driveways or places where vehicle movements are likely to take place we would suggest a heavier grade material that is designed for the job.


Frequently Asked Questions for DuPont™ Plantex® GroundGrid®
Application

How suitable is GroundGrid® for traffic applications?
As a general guideline, GroundGrid® should not be used for traffic areas with more than 50 vehicle movements per day.
For light traffic (private premises) the cell size 55 x 50 mm may be chosen. For more frequent or heavier traffic (up to 50 vehicle movement per day or occasional truck traffic) the cell size of 110 x 100 mm should be used.

Will the structure be solid enough to support the traffic or the operation of trucks or fire-fighting vehicles?
Yes. Trial installations have shown that truck traffic is no problem if driving with care. Simulations in an external institute mandated by DuPont have shown that the lateral extension levers of fire-fighting ladder-vehicles can be supported as well.

Can GroundGrid® be used for temporary installations and be removed afterwards? Is it recyclable?
GroundGrid® can be used for temporary installations. In this case it is important to install a strong geotextile below GroundGrid® so that the filling material can be easily collected, once the grids are lifted off the ground.
GroundGrid® is recyclable as a 100% polypropylene material. Recycling constraints may occur if GroundGrid® is extracted from an installation and is full of soil, dirt, or contaminated with any other particles.

Installation

How shall I install Plantex® GroundGrid®?
It is a 3-step process with the following steps (For detailed information, please refer to: www.plantexpro.dupont.com)
1) Remove the soil at a depth equivalent to the GroundGrid® cell height plus 3 cm. If installed on a slope, fix the grid with pegs at the edges. Lay out a geotextile if the soil is soft.
2) Stretch a GroundGrid® block to 8 m length. The cells need to be in contact with the ground at all times.
3) Fill all the cells with crushed gravel, add top cover of minimum 3 cm and compact. After installation, regularly check the coverage and fill up if needed. The Plantex® GroundGrid® cells need to be covered at all times.

What tools do I need for the GroundGrid® installation?
A rake (a shovel) to distribute the gravel into the cells, several pegs of 30cm to hold the grid temporarily, a stapler if several blocks are to be laid side by side (or following), a wooden board to walk on the cells when not filled.

Can I install it on my own or do I need second person to install?
It is possible to install GroundGrid® being alone. In this case one of the generally described installation step needs to be done differently.
The general process is that the grid is fixed on one side, then extended to 8m length, and then fixed on the other side. This procedure will not be possible for one person alone because the grid will shrink again when you put it down to plant the next 2 pegs. If alone, you first need to plant the pegs at the correct distances: you would plant 4 pegs forming a rectangle of 8m x 1,25m. Then you can slide the edge cells into all 4 pre-installed pegs.

What are the major errors to avoid and where do I need to pay most attention during installation?
Two errors are most common:
1) choosing the wrong cell size for a project, and
2) choosing the wrong gravel type

Any average installation time known?
The installation time will depend a lot on the shape of the project. A squared (rectangular) area will be most easy and quick to install. The preparation time to level the soil could be longer than actually installing and filling the cells. As a general guideline you may finish up 100 m² per day.
If your project includes a lot of corners where GroundGrid® needs to be cut to the correct size, or if you have a lot of blocks to be stapled together then it will take additional time.

What are the consequences of an incorrect installation?
The worst consequence would be that the cells show up above the gravel top layer and get deteriorated by car tyres. Therefore it is most important that the cells are covered all the time by a protective gravel layer.

Shall I use a geotextile underneath GroundGrid®?
This will depend on the actual subsoil present. A geotextile is recommended for following subsoil conditions
1) The subsoil is not stable (if you walk on the subsoil you will see your foot prints). In this case the geotextile layer will prevent the gravel to migrate into the subsoil (out from the cells into the soil). If installed without geotextile in this subsoil condition, the GroundGrid® cells will become visible on top and will be prone for deterioration, either by car tyres or by slow degradation from the UV rays from the sun.
2) When installing GroundGrid® on an area with former grass / wild vegetation, the geotextile will act as a weed control fabric and will prevent the weeds from growing through the gravel.
3) Sand: see 1: use a geotextile to prevent gravel from migrating into the sand.

Can it be installed on every ground structure?
Almost every ground. The ground needs to be somehow level, and stones of the size of the cells should be removed. The ground should not be too soft, otherwise even the installation of a geotextile can not prevent the deformation of the gravel layer.

Is there any border fixation recommended?
It is good practice to try to stabilize the borders in order to prevent the gravel from migrating away from the GroundGrid® cells. Commercially available products can be considered, as for example: concrete border slaps, metal rails, wooden boards, etc

Connecting several grids together with stapler: is it a durable solution (corrosion of staples)?
Connecting grids is especially required during installation (to align the cells during filling up) and during the first days or weeks of utilisation. When the gravel is well settled and compacted into the cells by regular use, the staples are no longer needed.

Can GroundGrid® be installed in slopes? What are the restrictions? How steep could a installation be to remain driveable?
GroundGrid® can be installed on slopes, but with special precautions. For a driveway the slope is limited to 5%, this means 5m height difference on a 100m long drive. If the GroundGrid® is not trafficked, then you may go up to a steepness of 50%, corresponding to an angle of about 30°. On slopes l ike that one can never walk on the GroundGrid® filled surface. You have to make sure that
1) the filling material is not compressible (not compactable i.e. no soil).
2) GroundGrid® is fixed at regular intervals to the underground with pegs.
3) The filling has to start from the bottom, going up, so that the top cells weight can rest on the bottom cells filling material.
4) You do not walk on such a steep slope.

What are the major errors to avoid during GroundGrid® installation in slopes?
See the 4 points of the preceding question.

Filling Materials

What gravel shall I use to fill Plantex® GroundGrid®?
The gravel size, the gravel shape and the gravel material is important. Gravel size:
for a cell diameter of 55mm the gravel size should be from 6 to 16mm;
for a cell diameter of 110mm the gravel size should be from 16 to 40mm
Gravel shape:
Only crushed, angular gravel shall be used
Gravel material:
If driving on GroundGrid® then “the more solid, the better” because the weight of the car will continuously abrade the gravel and could eventually transform the upper layer into sand particles. This is not good as the water permeability of the whole installation could eventually be lowered.

What happens if I take inappropriate gravel?
There are several drawbacks if the wrong gravel is used:
1) Wrong size: If the gravel size is too large for the cell size, there may be not enough gravel in one cell. The gravel will not stabilize the cell, GroundGrid® will be most likely twisted and deteriorate.
2) Wrong shape (i.e. rounded instead of crushed): If rounded gravel is used, the gravel might roll under the cells during (and possibly after) the installation. More gravel is required to fill the cells, the cells will tend to “rise up” above the gravel level. Car tyres may damage and deteriorate the cell material.
3) Wrong material (i.e. too soft for driving): The gravel will be crushed by the weight of the cars and consequently compacted in the cells. This may result in loss of good water permeability over time and/or gravel migration into the cells, consequently exposing the cell material to deterioration.

Can it be filled with soil and seed?
GroundGrid® can be filled with soil and seed if not intended to be used for traffic.

Can it be filled with sand? And used for pathways/driveways on sand?
Yes, sand is not compressible. However, a geotextile shall be installed underneath GroundGrid® to prevent the sand from migrating into the subsoil.

Can I use any type of gravel for the infill material?
No, only crushed, angular gravel must be used to fill the cells. Pea shingle or cobble type products may only be used as a decorative surcharge on top of the grid.

Which cell size should I use for my project?
The cell size is recommended in our application matrix The cell size will then determine the gravel size to be used:
for a cell diameter of 55mm the gravel size should be from 6 to 16mm;
for a cell diameter of 110mm the gravel size should be from 16 to 40mm

Procuct in use

What is the minimum resistance per m²?
Load bearing capacity of surfaces installed with Plantex® GroundGrid® depend on the subgrade bearing capacity, the infill material used and the compaction level, as the cells have no inherent resistance to vertical loads.
During Laboratory simulation, Plantex® GroundGrid® resisted to loads up to 340 ton/m² with minimum settlement, using a high quality infill material on a flat solid subbase."

Is GroundGrid® frost resistant?
Yes. The base material is polypropylene which does not take up water nor humidity. GroundGrid® stays flexible in frozen times.

How can I remove snow?
When shovelling snow make sure that you do not shovel away the upper protective gravel layer.

Can I put salt in winter without risking product deterioration?
Yes. The base material is polypropylene which is unaffected by most chemicals. Salt does not do any harm to polypropylene.

Can GroundGrid® support loads?
GroundGrid® can well support static loads of several tons, but it is not well suited to support dynamic loads such as car traffic with high speed accelerations or heavy breaking. GroundGrid® is not suited for heavy trafficked areas, such as large parking areas around supermarkets or shopping malls.

Can GroundGrid® be repaired? Can it be easily removed?
If damage occurs when GroundGrid® in use, we recommend to replace the damaged part grid. To do this, completely remove the gravel in the damaged area – if available with the help of an industrial vacuum cleaner. Then cut out the damaged cells and replaced them with a similar sized piece, fix by tuckering to the adjacent cells. Last step, refill all the cells and make sure that a topping layer is added.

If correctly installed, will GroundGrid® plus a geotextile function also as a weed control solution?
Absolutely.

Does GroundGrid® harm the environment?
There are no volatiles that will diffuse or leach out of the base material. There is no glue involved for the construction of the structure. Make sure that during installation all small cut-off pieces are properly collected. As the base material is polypropylene, the cut-offs may be disposed off in the regular household waste.

Is DuPont™ Plantex® GroundGrid® harmful to children or to pets?
No. The base material is inert and will not cause adverse affects to children or pets. There is no glue involved for the construction of the structure. Be sure, however, to dispose off properly of product packaging, particularly plastic wrapping, to prevent possible suffocation or ingestion by children or pets.

Can I drive on DuPont™ Plantex® GroundGrid®?
(See question on application above)

Case Studies