How Artificial Grass Should Be Installed

The existing turf and topsoil are removed to a depth of around 75 to 100mm below the intended finished level — deeper where the ground is soft, where the lawn will take heavy use, or where the grass runs up to a patio and must finish flush with it.

Finished level is set from the fixed points: paving, thresholds, existing steps and the base of any fence or wall. Artificial grass finishing proud of an adjacent patio looks wrong and creates a trip edge; finishing well below it looks sunken.

As with any groundwork, the finished surface must sit clear of the damp-proof course and must not block airbricks.

Excavated turf and soil have to leave site. On a typical Essex back garden that is a real tonnage, and it is why access strongly affects the price.

A geotextile membrane goes down on the exposed subsoil to separate it from the aggregate above and to suppress growth from below.

Then a compacted sub-base, usually MOT Type 1 or a granite equivalent, is laid and whacked in layers. For a lawn area, 50 to 75mm compacted is typical; more where the ground is soft or the area will be heavily used.

On heavy clay, or where the garden already sits wet, additional drainage is needed before the grass goes down. Artificial grass backing is permeable, but water still has to leave the sub-base — laying permeable grass over impermeable ground simply moves the puddle underneath.

That may mean a land drain to a suitable outfall, or a deeper open-graded stone layer to act as a reservoir. This is the single most commonly skipped stage, and it is why so many artificial lawns squelch in winter.

A firm perimeter is essential. Treated timber battens, composite edging or a concrete haunched edge all work; the grass is fixed to it so that the perimeter cannot lift or creep.

Where the lawn meets a patio or path, the grass is fixed to the paving edge directly. Where it meets a border or fence, an edging is installed and set to the correct height first.

On top of the compacted sub-base goes a laying course of sharp sand or granite dust, typically 20 to 25mm, screeded and compacted to a smooth, true surface. This is what determines whether the finished lawn looks flat or shows every lump beneath it.

Take the time to check this layer with a straight edge before any grass is unrolled. Every imperfection in the laying course shows in the finished surface, and it cannot be corrected afterwards.

A second weed membrane goes over the laying course, then the grass is rolled out and left to relax for several hours — ideally in sunshine — before any fixing. Grass laid straight off the roll and fixed immediately will develop ripples as it settles.

Pile direction matters enormously and must be consistent across the whole lawn. Every piece should run the same way, and conventionally the pile leans towards the main viewpoint, usually the house, which makes the lawn look fuller.

Joins are where installations are judged. The selvedge is trimmed from both edges, the pieces are butted — not overlapped and not gapped — over jointing tape, and glued with a proper two-part adhesive. Pile at the join is teased free of adhesive so the seam disappears.

A join done well is invisible. A join done badly shows as a line for the life of the lawn, and it is the most common complaint about cheap installations. Where possible, plan the layout so that joins fall in less prominent areas.

The perimeter is fixed to the edging with galvanised or stainless nails or staples at close centres, or glued to paving edges with adhesive. Fixings should be driven at a slight angle and set below the pile so they are invisible and cannot work up.

Kiln-dried silica sand infill is then brushed into the pile. It weighs the lawn down, holds the fibres upright, protects the backing from UV and makes the surface feel more natural underfoot.

Some installers skip infill on shorter piles to save time and cost. It is worth having on almost every lawn — an infilled lawn holds its appearance far longer and is much less prone to rippling in heat.

For pet owners, a specific antimicrobial or zeolite-based infill helps with odour, and the sub-base should be free-draining so urine flushes through rather than sitting.

Finally the pile is brushed up with a stiff power brush or a specialist rake, which lifts the fibres and settles the sand evenly.

Ripples and bubbles mean the grass was not left to relax before fixing, or the perimeter fixings are too far apart, or there is no infill to hold it down. Heat expansion then has nowhere to go.

Standing water means the sub-base or the ground beneath cannot drain. The grass itself is almost never the cause.

Weeds appearing through the surface almost always germinate in debris on top rather than growing up from below — the fix is regular brushing and clearing rather than a stronger membrane.

A flattened pile in a walked-through route is normal wear, but a lawn that flattens everywhere within a year usually means a low-grade grass with poor fibre memory, or no infill supporting the pile.

Visible joins mean overlapped or gapped seams, inconsistent pile direction, or adhesive contaminating the pile. None of these can be corrected without re-doing the join.