In short: Artificial grass goes on concrete by cleaning the slab, checking it drains, laying foam underlay, keeping the pile in one direction and fixing edges with outdoor adhesive or strong tape. Excel Deco on Moi Avenue, Nairobi sells 20 to 35mm artificial grass at KSh 999 to KSh 1,399 per sqm and can install it for you.

How to lay grass on concrete

1. Clean the surface. Sweep, scrub off moss and let the concrete dry.
2. Check drainage. Make sure water runs to a drain. Cut holes in the grass over any drain.
3. Lay the underlay. Roll out a foam underlay if you want a softer feel.
4. Roll out the grass. Lay each piece with the pile leaning the same way and let it settle for an hour.
5. Join the pieces. Use joining tape and glue under the seams.
6. Fix and brush. Glue or tape the edges, trim the borders and brush the pile up.

Prepare the concrete first

Grass on concrete is only as good as the slab under it. Spend most of your effort here.

• Sweep and wash. Remove sand, moss, oil stains and loose cement. Let it dry fully.
• Check the fall. Pour a bucket of water on the slab. Watch where it goes. If it pools, those low spots need filling with a cement mix before you lay grass.
• Clear the drains. Make sure the outlet is open and that the grass will not cover it.
• Fix cracks and broken edges. They show through as dips over time.
• Measure. Measure at the longest and widest points and note where the slab meets walls, steps and pots.

Good drainage matters most in the long rains. Water that sits under the grass for days brings smells and moss.

If your slab has a gentle fall towards a drain, you are in good shape. A perfectly flat slab with no fall is harder. Talk to us before you buy so we can plan where the water goes.

Step by step on a concrete slab

1. Roll out the foam underlay across the slab, butted edge to edge. Tape the joins. This makes the grass softer and kinder to knees.
2. Unroll the grass and let it rest in the sun for an hour or two so it lies flat.
3. Check the pile direction. Every piece must face the same way or the joins will show as a colour change.
4. Trim the edges from the back with a sharp knife, cutting between rows of stitches.
5. Join the pieces with joining tape and outdoor adhesive under the seam. Press the two edges together tightly.
6. Fix the edges with outdoor adhesive or strong tape so wind and feet cannot lift them.
7. Brush the pile up with a stiff broom against the grain to stand the fibres up.

Cost worked out: a rooftop terrace in Westlands

Take a rooftop terrace measuring 4 by 5 metres. That is 20 sqm.

• Entry level 20mm grass at KSh 999: 20 x 999 = KSh 19,980
• Thicker 35mm grass at KSh 1,399: 20 x 1,399 = KSh 27,980

Foam underlay and fitting are quoted on WhatsApp. Send a photo of the slab and the drain points to 0757 753 748. Thicker grass looks fuller and feels softer. On a rooftop where people sit and children play, we usually suggest the thicker range plus underlay. For smaller spaces, see artificial grass for balconies. For a full garden on soil, see artificial grass for gardens.

Care in Nairobi dust and rain

• Brush the pile every few weeks to keep it upright.
• Hose it down in the dry season to wash off dust.
• Blow or rake off leaves before they rot in the rains.
• Rinse pet areas often with plain water.
• Keep jikos, grills and cigarettes off the grass. Heat melts the fibres.
• Check the edges after heavy storms and press down any that lifted.

Still deciding? Our guide on artificial grass vs real grass compares cost, water and care.

Shop the products on this page

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Questions buyers ask

Do I need glue on concrete?

On balconies and windy rooftops, fix the edges. Small areas can be held with tape.

Will water pool under the grass?

Not if the concrete falls toward a drain. The backing has drainage holes.

Which thickness is best on concrete?

20mm to 30mm, ideally with an underlay.

Can Excel Deco install it?

Ask us on WhatsApp about fitting.

Can I put artificial grass on a rooftop?

Yes, as long as the slab drains well and the drain outlets stay open. A foam underlay makes it softer and protects the slab.

How do I join two pieces of grass?

Lay both pieces with the pile facing the same way, then glue them onto joining tape with outdoor adhesive. Press the edges tight so no gap shows.

Can I lay artificial grass on outdoor tiles?

Yes, the method is the same as for concrete. The tiles must be firm and the surface must drain so water does not sit under the grass.

Shop and read next

• Grass for balconies
• Artificial grass
• Artificial grass price
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