By this stage you should already have:

• a fully compacted sub-base
• a non-woven membrane laid flat
• a level screed layer

If that’s done properly, installing the grids is straightforward.

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Step 1: Understand your edge restraint (before laying grids)

Edge restraint is essential, but it does not always happen at the same stage, and it does not have to be the same on every side.

In real DIY projects, edges are often a mix of existing and new restraints.

Examples from my own builds

Driveway

• Existing pin kerbs on most sides
• Neighbour’s concrete driveway formed the solid edge on the remaining side

Garden / sauna base

• Rear edge: existing retaining wall
• Right-hand edge: existing concrete base
• Front edge: timber border made from treated 4×1
• Left-hand edge: excavation edge against firm soil ground

This worked because every edge was either:

• already solid and immovable, or
• restrained where movement was possible

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The rule that actually matters

You do not need identical edging on every side.

What matters is:

• any edge that can move must be restrained
• any edge that is already relatively solid can be relied on

Use this simple check:

• Edge against concrete, brick, stone, wall, or kerb → no extra restraint needed
• Edge against soil or garden ground → add a restraint.

For a simple base timber edging will usually be fine. If this is your driveway you might consider adding something a little more robust like concrete edging, kerb, or stone.

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Step 2: Dry-lay grids before committing

Before locking anything together:

• place a few grids loosely on the screed layer
• check alignment and orientation
• identify awkward cuts early

This avoids locking yourself into a bad starting point.

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Step 3: Start from a straight reference edge

Where possible begin grid installation from:

• a kerb
• a wall
• a straight timber edge
• an existing hard surface

Don’t start in the middle and work outwards. The only caveat to this is a situation where you are joining two areas. For example, on my driveway it connected to a path. To ensure the grids aligned I had to start here.

If the first grids go in correctly, the rest will follow easily.

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Step 4: Laying the grids

• Lay grids directly onto the screed layer
• Press them down gently by hand
• Ensure each grid sits fully supported

Grids should:

• sit flat
• not rock
• not bridge over high spots

If a grid rocks, lift it and adjust the screed layer slightly underneath. Don’t force it down.

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Step 5: Locking grids together

• Lock grids together as you go
• Make sure each joint is fully engaged
• Don’t skip sections and come back later

Poorly locked grids can:

• spread under load
• lift at the edges
• allow gravel to escape over time

The good news is grids do lock together very easily, so this part is actually extremely easy.

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Step 6: Cutting grids

Grids are easy to cut but it can be messy.

Common tools:

• jigsaw
• handsaw (slower, but works)

Tips:

• mark cuts clearly
• cut slightly oversized and trim back (you can take it off, but you can’t put it back on)
• dry-fit before moving on

Wear eye protection. Plastic fragments can go everywhere when cutting.

Step 7: Final checks before infill

Before adding gravel:

• walk the surface
• check for rocking grids (don’t worry about very small movement)
• check edges and transitions
• correct any issues now

Once infilled, adjustments are far harder.

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Common mistakes to avoid

• Assuming every edge needs the same restraint
• Starting from a crooked reference line
• Forcing grids onto uneven screed
• Leaving grids partially unlocked
• Relying on gravel to “fix” alignment

Grids preserve mistakes, they don’t hide them.

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The takeaway

Grid installation isn’t difficult, but it rewards patience and planning.

If you:

• understand which edges actually need restraint
• start from a straight reference
• keep grids flat and fully locked

You end up with a stable surface that won’t creep or spread over time.