Paving grids are commonly used at the sub-base layer in construction and landscaping projects. They reinforce the ground to make it level and stable so that it is safe to walk or drive on. Some projects might require stronger grids depending on the intended use of the area.
For instance, the grids recommended for constructing a pedestrian pathway and a car park will be different because car parks need a stronger & deeper grid to support the weight of multiple vehicles.
Find out What Paving Grids Can Be Used For?
Ask The Right Questions
No matter what you need the paving grids for, there are always a lot of products to choose from. But how do we know if they are any good?
Download this simple checklist to see if the grid you want to buy ticks all the boxes.
Keep reading to see the 12 important points we think would make a good grid.
What should you watch out for if you want to get a plastic permeable paving grid?
A permeable SuDS compliant grass or gravel system is a great way to mitigate flood risk and install a highly effective grass of gravel parking or roadway system, however……
1. Do the grids lock together without separate pins or clips?
Apart from the fact that the actual fitting time is vastly increased, pins and clips can fail, pins often are not able to be firmly forced into the ground due to stone, clay or roots.
2. When grids are fitted together, can they be taken apart relatively easily?
Very often grids slide easily together with thin lugs or catch on the side, some have circular designs. Check that they cannot easily be taken apart. If they can, then any traffic either vehicular or pedestrian is likely to ‘bounce’ the grids apart causing failure and health and safety problems.
3. Do the grids have in-built pins on the base?
Pins fitted to the base of grids are there to secure the grids in place, however, these pins often cause problems in themselves due to problems with stony or ground with lots of roots. Roots can also grow around grids forcing them out of the ground, again causing failure.
4. Do the grids seem of flimsy construction?
The weight of any grid that is designed to allow traffic over it has to be in excess of 5.6kg per square metre, and less weight simply means less material in the grid; which in turn will mean a cheaper construction. You get that which you pay for!
5. Do the grids have an attached membrane?
Plastic permeable paving does indeed need a membrane within the construction process, however, this membrane needs to be as a filtration and separation layer below the screed level and on the top of the hard-core layer. Some honeycomb-style grids have a welded membrane. The British standard for these products is a minimum of 100g per square metre with a minimum strength level known as cone drop efficiency. Any less than 80g and the membrane is less than useful.
6. Has the grid range been independently tested?
Many manufacturers make wild claims about the loading or weight of vehicles that can go over the grids, can these claims be substantiated? If not, one has to question the validity and therefore the suitability of the product.
7. What guarantee is offered on the product?
If a manufacturer is confident in the quality of its products, then said the manufacturer will be only too happy to offer a guarantee of 20 years. Also, check that the manufacturer can offer case studies that cover the guarantee period to prove effectiveness. A guarantee is only as good as the company backing it up.
8. Is the grid UV stable?
It is substantially cheaper when making grids to not add a UV stabilising agent, however, the grids will fail relatively quickly. They will also bleach in sunlight which is a sure sign of no UV protection.
9. What size are the individual grids?
For any kind of groundwork, the smaller the product the better, this being proven with concrete blocks or cobbles which have been around since the Romans perfected the construction of roadways. With plastic grids, you should choose a range that has a minimum of 6-9 per square metre. The larger paving grids which usually have around four per square metre can ‘bridge’ voids in the ground when there is a natural ‘heave’. Such voids cause the grids to effectively bounce apart and ultimately fail.
10. Is the product made from flexible plastic?
Flexibility is key with these products, they move, expand and contract. LDPE (low-density polyethylene) is the best material; HDPE can be very inflexible, brittle and can cause failure in the installation.
11. Is the grid material frost-proof?
Sounds obvious but check, many are not.
12. Do your research
The last one is all about you, are you confident in your chosen product? Does it tick all of the boxes above? Remember that your installation will be expected to last well over 20 years.
They may all look similar, but it is the detail that makes the difference. Sub-base should be built to last, pay attention to detail, and installing high-quality grids is the long-term solution!
EcoGrid is known worldwide to have achieved all those points and more. Manufactured from specially selected recycled plastic that follows strict recycling controls; over 15 million grids were produced and used for various projects globally since 2017.