How to lay gravel grids

Use this comprehensive guide to find out how to install gravel grids on any site. This guide was written by the founder of industry leading manufacturer, IBRAN. It draws on over 10 years of experience of developing our product and helping over 100,000 gravel grid installation projects in that time.

This guide provides you with ideas on how to lay a plastic grid driveway on virtually any site.

Follow the steps outlined to create the perfect gravel grid driveway:

Step 1 - Measure Up

1. Take Measurements
2. Do you need a sub base?

Step 2 - Order the right materials

1. Order geotextile for above and below sub base.
2. Calculate and order sub base materials for 150mm depth
3. Calculate number of gravel grids by multiplying m² by 4.
4. Order edging components and ramps for installation on concrete.

Step 3 - Prepare the sub base

1. Excavate to a minimum of 210mm depth.
2. Line the level ground with permeable geotextile.
3. Fill with 150mm of compacted type 1/2/3 MOT sub base.
4. Cover with 10mm levelled sharp sand
5. Line sharp sand with permeable membrane

Step 4 - Lay gravel grids

Step 5 - Fill with gravel

Step 1 - Measure Up the Site

As with any project, it's important to prepare well. This means taking accurate measurements of the area you are hoping to fit the gravel grids to. It's unlikely that your driveway is perfectly square, so it might be better to break down the area into a series of square sections you can take measurements from.

Take the length and width of each section to give you the area. Add the sum of these sections together to give you a rough total of the total area of surface you are laying the grids down in. Use our area calculator and make sure to round up your measurements to the nearest 0.5m. It's helpful to add 5% to this total to allow for cuts.

Working in feet and inches? Convert your measurements to metric to order the right amount.

Look at your site carefully. Are you creating a new surface or replacing an existing surface?

Existing surface

If your area already has an existing surface, such as concrete, tarmac or block paving, consider whether you need to remove that surface or not. If the site is badly broken down, it could be a sign that the sub base beneath is failing or that there are poor drainage issues.

• Are there large breakages in the concrete?
• Does the budget allow for a complete removal of the existing surface?
• How long has the existing surfacing been down?
• What vehicles do you intend to drive over the site?

With this knowledge, you need to decide whether to replace the surface completely or simply lay the grids over the top.

If your site has poor drainage and you regularly get floods or pools of water building up, consider how you will get rid of this water. Is a surface water drainage solution needed?

If you're laying gravel grids on top of concrete, tarmac or block, you will want to make sure you order sand and sub base to fill in the holes and voids in the surface. This will help support your new gravel grid surface later.

You'll also want to make sure your new grid surface has appropriate ramp edging gravel for grids at the front and border edging for the sides.

New surfaces

If you're starting from scratch, ensuring your gravel grids last a long time requires you to think carefully about what kind of foundation you give the grids. To determine what kind of foundation you need for driveway grids, think about things like:

• Will vehicles be driving over the grids? If so, what kind of vehicles?
• What kind of soil type do I have? Is it free draining?

When carrying out any surfacing project for motorbikes, cars, vans and trucks, you cannot afford to bypass installing a sub base. It's the foundation that holds up the entire project.

Without a fixed sub base, you're relying on shrinking and expanding soil (particularly clay-based soils) that moves to support something designed to stay still. The grids would slide around between your car tyres and the soil like a bedsheet through a mangle.

Added to this, if your soil struggles with drainage and gets waterlogged, laying a sub base beneath your grids will aid with the absorption of this water. It creates a permeable layer that allows rainwater to move to the sub soil.

Step 2 - Ordering materials

No project is ready to complete without a list of materials and a schedule of when they're being delivered. Having an idea of delivery dates helps you to plan when you're going to start which phase of the installation. Having enough materials to complete the project ensures that there are no unnecessary hold ups.

Ordering your Sub Base Materials

Now that you've decided whether or not to install a sub base, it's worth calculating exactly how much you need to ensure you have the right foundation. We always talk extensively about getting the foundations right and that's because we want your new surface to last the test of time.

Your sub base should be at least 150mm deep when compacted.

Beneath every good sub base, is a permeable geotextile/membrane that allows water to trickle through to the soil below. On top of every sub base, is a levelled layer of sand and another membrane to stop the grids migrating through the layers.

Within the grids, you can put any 10-30mm stone you like the most of but bear in mind that the smaller it is, the more likely the stone gets stuck in tyres. Using stone larger than 30mm will make it awkward to fill. For best results for your driveway, a 20mm angular gravel is best.

Calculating how much of these you need for a 150mm deep sub base is very simple, thanks to these useful tools:

Ordering Gravel Grids

The most important step of all - ensuring you have enough grids to completely cover the area you've measured.

To do this you'll need to calculate how many IBRAN-X gravel grids your site needs. Fortunately this is as simple as multiplying the area you measured earlier by four.

For example, if your site measures 13m x 6m (78m²), you would need 312 grids.

Additional components

As well as ordering the membrane, sub base and grids, you might want to consider adding a few components to the installation to ensure that the surface is complete, fully functioning and durable for longer.

These are some of the products worth considering:

Gravel Grid Ramp Edging

If you've decided to install the grids over an existing surface, you will need edging ramps to ensure that the entrance is protected and anchored. These ramps should be bolted down using 12mm expansion bolts.

Border Edging

These border edging strips attach directly onto the connectors of the grids, providing a solid division between your gravel surface and adjoining borders and lawns

They can be used to anchor your gravel grid installation on top of an existing surface. They have holes through which you push ground anchors. For installations adjoining grass, the edging strips are packaged with anchor pegs.

Step 3 - Preparing the Sub Base

Now that you have your materials on order and scheduled for delivery, it's time to prepare the site for installation. If you're installing you gravel grids on concrete, you can skip the excavation step of the guide.

Getting your levels right

The key to a good sub base is getting enough material in, compacting it and ensuring that it is level.

How deep your excavation should be

The site is now ready for digging out. Using our recommendations, you should dig to a minimum depth of 210mm to allow for the sub base, sand, grids and stone overfill.

To save yourself many painful hours of digging, consider hiring a mini-digger to speed up the process.

Grade the surface and line with a permeable geotextile membrane. This membrane allows water to pass through to the ground layer, whilst also stopping the sub base from sinking.

Levelling your surface with sharp sand

This step keeps your grids level and ensures that they connect to each other directly and without additional twisting.

For this, you will need at least 10mm of sharp sand to "blind" the surface. This sand is evenly spread across the entire sub base layer, before it is smoothed level and compacted. This layer protects the weed suppressant membrane and also stops the sub base moving through into the grid layer.

Finally to separate the sand and the grids and to minimise weed growth, install a weed suppressant membrane over the sand.

Filling in any holes

This step applies only to installations on existing concrete or tarmac surfaces.

The reason most people choose to replace a concrete or tarmac surface is because it is extremely broken and unsightly. Installing gravel grids on top of concrete or tarmac is possible but you should fill in any holes with type 1 MOT and sand.

Now that your surface is ready, you can start to work on laying gravel grids.

Step 4 - Laying gravel grids

This is the step where you really start to see the transformation begin. This is a really satisfying process where the grids quickly connect to one another and form one continuous surface over the membrane ready for your stone.

Orientate all of your grids the same way in the same row. Keep the male connectors on the bottom and right hand side of the grids as you lay them. Work upwards and back, interlocking one row at a time, pushing the female connectors down onto the male connectors.

When you get to the edges, you may need to cut the grids to fit the shape of the area you're installing within. This can be done with any saw but a jigsaw is the preferred choice.

Make sure your edges are well bound into the sides of your area. This tight fit keeps the grids from moving around when driven over. If you're using an edging product, now is the time to use them.

Check over the surfaces and make sure there are no hidden bumps or lumps. The grids need to sit level on the ground.

Step 5 - Filling with stone

The final stage of your installation is filling in the cells with gravel.

We recommended using 20mm angular gravel but you could just as well fill them with anything that you prefer the look of. 10mm gravel is great for areas without much vehicle use. 30mm gravel works well with areas designed for wheelchair users.

Some installers like to compact the stone within the cells using the whacker plate used for the sub base. It's not necessary to do this but it does aid compaction at the lower parts of the cells.

Your gravel driveway is now ready for use!

For more info, remember IBRAN-X is the only system designed to help you install your gravel grids on virtually any site.