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Concrete patios and back yards are one of the most common outdoor surfaces in UK homes. They are practical and durable, but they are also hard, cold, grey, and uninviting. A lot of people want to cover them with something better.

Laying artificial grass on concrete is one of the most popular ways to do exactly that. It is quicker and cheaper than digging out a concrete base and starting from scratch. And when it is done correctly, the result looks and feels genuinely good.

I have put this guide together to walk you through the full process step by step. We cover how to assess your concrete, how to deal with drainage, how to lay the underlay, how to fix the grass down, and how to finish the edges cleanly. We also cover the most common mistakes so you can avoid the problems that trip up a lot of DIY installs.

Can You Lay Artificial Grass Directly on Concrete?

Yes. Artificial grass can be laid directly on concrete, patio slabs, tarmac, and most other solid hard surfaces. The key conditions are that the base must be structurally sound, reasonably level, and able to drain water effectively.

The main advantage of installing artificial grass on concrete is that you skip the groundwork entirely. There is no digging, no hardcore sub-base to lay, and no compaction required. The concrete itself acts as your solid base.

The process is also significantly faster than a soil installation. A typical concrete patio of 20 to 30 square metres can be done in a single day by a competent DIYer working alone.

Tools and Materials You Will Need

Step 1: Assess Your Concrete Surface

Not all concrete surfaces are suitable for direct artificial grass installation. Before you order anything, assess the base carefully.

What to Check

• Structural integrity: Press and tap across the surface. Any areas that sound hollow or feel soft indicate loose or damaged concrete. Sections that move underfoot need to be fixed or removed before installation.

• Cracks: Minor hairline cracks and small surface cracks are acceptable and can be filled. Large cracks wider than 20mm that have caused sections to lift or shift need to be repaired properly first. Large structural cracks that run right through the slab are a warning sign that the whole base may need attention.

• Level: Check the surface with a spirit level. Small undulations of a few millimetres are acceptable and the foam underlay will absorb them. Significant dips or humps of more than 10mm will show through the finished grass surface.

• Drainage: Hose down the surface and watch where the water goes. Ideally, your concrete has a slight fall that causes water to run off the edge. If puddles form in one or more areas, you need to address drainage before laying the grass.

How to Fix Drainage Problems

If your concrete holds water in puddles, drill drainage holes using a 16mm masonry bit. Drill holes at each point where water pools, then fill each hole with 10mm pea gravel or shingle. This creates a drainage path for water to escape through the base.

Apply a glue coat around the perimeter of these drainage holes when you fix the grass, leaving a 20mm gap in the adhesive at each hole location so water can still escape through to the gravel below.

Step 2: Clean and Prepare the Surface

A clean surface is essential for the adhesive to bond correctly. Any oil, grease, moss, algae, or loose debris between the concrete and the adhesive will cause the bond to fail over time.

1. Sweep the entire surface to remove loose dirt, leaves, and debris.

2. Pressure wash or scrub with a stiff brush and soapy water to remove algae, moss, and surface grime. Pay extra attention to corners and edges where moss tends to accumulate.

3. Allow the surface to dry completely. Adhesive does not bond well to damp concrete. If you are working in spring or autumn, allow at least 24 hours after washing before you proceed.

4. Fill any cracks or dips with a crack filler compound or self-levelling mix. Follow the product instructions for drying time before moving on.

Step 3: Measure and Cut Your Grass

Measure the length and width of your area carefully. Add 50 to 75mm of extra length on all sides. This gives you material to trim neatly to the edges without any risk of coming up short.

Artificial grass comes in rolls of set widths, typically 2m, 4m, or 5m. Choose a roll width that minimises joins across your space. A join running across the middle of a visible area is hard to disguise completely. If possible, use a single roll wide enough to cover the full width.

If your space is wider than one roll, plan where the join will fall. Joins should run parallel to the main viewing direction, ideally in a low-traffic area. You can browse our artificial grass range at The Outdoor Look, which includes a variety of roll widths to suit most garden sizes.

Step 4: Lay the Foam Underlay

Foam underlay is strongly recommended for any artificial grass installation on concrete. It serves two purposes: it smooths over minor surface imperfections and irregularities, and it makes the finished surface noticeably softer and more comfortable underfoot.

Choose a foam underlay of at least 7mm thickness for a garden or patio. For a children's play area or a space where people will sit or play on the surface, a 10mm underlay gives better cushioning. Use a free-draining underlay rather than a solid foam sheet that traps water.

1. Roll out the underlay across the clean, dry concrete surface.

2. Cut to fit using a sharp utility knife. Butt the edges tightly together without overlapping. Overlapping underlay creates a ridge that shows through the finished grass.

3. Secure the underlay to the concrete using a multi-purpose adhesive applied around the perimeter and in several strips across the surface. Apply the adhesive to the concrete, wait 10 to 15 minutes for it to become tacky, then press the underlay down firmly.

4. Allow the adhesive to cure for at least 30 minutes before laying the grass on top.

Step 5: Lay the Artificial Grass

This step requires care to get the pile direction right and to allow the grass to settle before you make your final cuts.

• Roll the artificial grass out onto the underlay. Do not drag it, as dragging can disturb the underlay beneath.

• Check the pile direction. The pile is the grass fibres, and they naturally lean in one direction. For the most natural appearance, position the grass so the pile leans away from the main viewing point. Looking at the grass from indoors, the fibres should lean towards you.

• Leave the grass to settle for 2 to 3 hours. This allows any creases from being rolled to relax and flatten out. Do not cut or fix until the grass has fully settled.

• Once settled, trim the edges carefully with a sharp utility knife. Cut along the stitch lines on the back of the grass rather than through the fibres. Cutting between stitch lines creates a clean edge with no loose fibres.

• Allow 5 to 10mm of extra grass at each edge before making your final trim. This small amount of overhang is folded under or pressed flush against the edging when the grass is glued down.

Step 6: Fix the Grass to the Concrete

Fixing the artificial grass securely is what separates a professional-looking result from one that lifts, creases, or moves underfoot over time.

Apply the adhesive around the full perimeter of the area, running a bead of glue onto the concrete about 75mm wide. Leave drainage gaps of 20mm at intervals, especially where you drilled drainage holes. Do not apply adhesive in a solid ring with no breaks at all, as this can trap water under the grass.

Fold back the grass edge, apply the adhesive, wait for it to become tacky following the product instructions, then press the grass edge firmly down into the adhesive. Place weights or sandbags along all glued edges while the adhesive cures. Most adhesives require 2 to 4 hours before the weight can be removed.

For larger areas, you can also apply adhesive in strips across the surface beneath the grass rather than just at the perimeter. This is recommended for any area over 20 square metres or any space with heavy furniture on it.

Step 7: Joining Two Pieces of Grass

If your space requires two rolls of grass, joining them correctly is critical. A visible or poorly joined seam is the most common complaint with DIY artificial grass installations.

• Both pieces must have the pile running in the same direction. Always check this before cutting.

• Trim the factory edge from each piece along the stitch line to create a clean cut edge. The salvage edge of artificial grass has a reinforced border that creates a visible ridge if left in place.

• Lay the jointing tape face down along the centre line of the join. Apply the joining adhesive in a zig-zag pattern along the tape.

• Pull the two grass edges together over the tape and press down firmly. Ruffle the fibres at the join with your fingers to disguise the seam line.

• Place weights along the join for at least 2 hours while the adhesive cures.

Step 8: Add Kiln-Dried Sand Infill

Sand infill is the final step and one that many DIYers skip. Do not skip it. Sand infill serves an important practical purpose.

Spread kiln-dried silica sand evenly across the surface at a rate of 4 to 6 kilograms per square metre. Use a stiff-bristled broom to brush the sand down into the base of the pile. The sand weighs the grass down, keeps it flat, stops fibres from matting, and helps the blades stand upright for a more natural appearance.

Once the sand is brushed in, give the whole surface a final brush against the pile direction to lift the fibres. Then step back and check the surface for any creases, lifted edges, or areas that need a final trim.

Common Mistakes to Avoid

Not testing drainage before installation. If your concrete holds water and you lay grass over it without addressing the problem, you will end up with a damp, smelly surface that encourages mould growth. Always test drainage first and drill holes where needed.

Skipping the foam underlay. Laying artificial grass directly onto bare concrete feels hard and uncomfortable underfoot. The surface is also more likely to show imperfections and feels less like natural grass. Underlay is a small additional cost that makes a noticeable difference.

Using the wrong adhesive. Standard wood glue, general-purpose PVA, and mastic are not suitable for bonding artificial grass to concrete. Use a purpose-made artificial grass adhesive or a two-part multi-purpose construction adhesive specified for outdoor use on porous and non-porous surfaces.

Cutting across stitch lines. Always cut along the stitch lines on the reverse of the grass. Cutting across them leaves loose fibres at the edge that pull out over time, giving a frayed, untidy finish.

Laying grass in the wrong pile direction. If you are joining two pieces, both pieces must have the pile running in the same direction. Different pile directions on adjacent pieces create a patchwork effect that is very difficult to disguise.

Quick Reference: Concrete Suitability Check

For further information on DIY artificial grass installation standards and product specifications, the Landscape Institute publishes guidance on artificial surface installations at landscapeinstitute.org, which covers professional standards that inform good DIY practice.

Pro Tips From Experience

The best time to install artificial grass on concrete in the UK is spring or early autumn. Mild temperatures help adhesive set at the right rate. Very cold weather slows curing significantly. Very hot weather causes adhesive to skin over too quickly before you press the grass down.

If your concrete area includes a manhole cover, do not cover it with grass and adhesive. Instead, cut the grass neatly around the manhole frame and leave it accessible. You can buy purpose-made grass manhole cover inserts that allow access while looking neat from above.

When trimming the final edges, use a fresh sharp blade for every 3 to 4 metres of cut. Blunt blades drag and tear the grass backing rather than cutting cleanly. Spare blades are cheap and make a real difference to the finish.

Frequently Asked Questions

Q: Do I need to use underlay when laying artificial grass on concrete?

We strongly recommend using underlay. Laying artificial grass directly on bare concrete creates a surface that feels hard and uncomfortable underfoot. Foam underlay of at least 7mm thickness smooths over minor surface imperfections, makes the grass feel softer, and improves the overall appearance of the finished surface. For children's play areas, a 10mm or thicker underlay is advisable for extra cushioning. The additional cost of underlay is small relative to the overall project, and the improvement in feel and finish is significant.

Q: How do I stop artificial grass from lifting at the edges on concrete?

The most reliable way to prevent edge lifting is to apply a continuous bead of outdoor adhesive around the full perimeter of the area, pressing the grass edge firmly into the glue and weighting it down for at least two hours while it cures. Leave small drainage gaps in the adhesive rather than creating a fully sealed perimeter. For large areas, apply additional adhesive strips across the surface beneath the grass rather than just at the edges. On very exposed or windy locations, additional adhesive coverage beneath the grass gives the best long-term result.

Q: How do I deal with poor drainage when laying artificial grass on concrete?

If your concrete holds water in puddles, drill drainage holes before laying the grass. Use a 16mm masonry drill bit and drill holes at each point where water pools. Fill each hole with 10mm pea gravel or shingle. When applying the perimeter adhesive, leave 20mm gaps in the glue at intervals and at each drainage hole location so water can still escape. Using a foam underlay with drainage holes rather than a solid sheet underlay also helps water pass through the system rather than pooling beneath the grass.

Q: Can I lay artificial grass on cracked or uneven concrete?

It depends on the severity. Minor hairline cracks and small surface cracks can be filled with a crack filler or self-levelling compound before installation. Small undulations of a few millimetres are absorbed by the foam underlay. Large cracks wider than 20mm that have caused sections to lift or shift need to be repaired before you lay the grass. Very uneven surfaces with dips or humps of more than 10mm should be levelled with a self-levelling compound. If sections of concrete are loose, rocky, or structurally compromised, those sections should be fixed or removed before any artificial grass installation.