Quick Answer: The best base for artificial grass in UK gardens is a compacted MOT Type 1 hardcore sub-base (50–60mm) topped with 10–15mm sharp sand or grano dust, plus a permeable weed membrane. For concrete or decking, use a drainage foam underlay instead.
When you’re laying artificial grass, what goes underneath it is just as important as the turf itself. The right base layer keeps your lawn stable, helps it drain properly, and makes sure it looks good for years. Skip it, and you’ll end up with dips, puddles, or weeds pushing through.
At As Good As Grass, we’ve been installing lawns for over 20 years across Greater Manchester and the North West. Here’s our guide to the best materials to use under artificial grass — whether you’re a DIYer or booking our team for a professional fit.
Why the Base Matters
Artificial grass isn’t just rolled out and left. It needs a solid foundation. A proper base does four key things:
- Stability – prevents your lawn from sinking or rippling.
- Drainage – stops water pooling and mould growth.
- Weed prevention – blocks weeds forcing their way up.
- Comfort – softer, safer ground for pets and children.
Planning a full install? See our artificial grass installation service.
What Is the Best Material to Put Under Artificial Grass?
The best base depends on where you’re installing. For most UK gardens, here’s what we recommend:
- MOT Type 1 Hardcore (Crushed Stone/Gravel) – The gold standard. It locks tight when compacted, drains well, and keeps your lawn stable for the long term.
- Sharp Sand, Grano Dust, or Limestone Fines – Used as a thin top layer (10–15 mm) for levelling. Grano dust gives a firmer finish — great if you’ve got pets.
- Foam Underlay – For hard surfaces like concrete or decking, a 5–10 mm free-drainage foam pad makes the lawn feel softer and masks minor cracks.
- Shockpad / Safety Padding – Required in schools and nurseries, or anywhere kids might fall from height. Adds protection and comfort.
Learn more about our artificial grass for schools and nurseries.
Sub-Base Options Compared
| Base Material | Pros | Best For |
|---|---|---|
| MOT Type 1 | Strong, stable, long-lasting, drains well | Most UK gardens, heavy traffic areas |
| Sharp Sand | Easy to level, budget-friendly | Small domestic gardens |
| Grano Dust | Firm finish, great drainage, resists dog urine | Pet-friendly installations |
| Foam Underlay | Adds softness, masks minor cracks | Concrete, patios, decking |
Do I Need a Weed Membrane Under Artificial Grass?
Yes – always. A permeable weed membrane stops weeds growing through without blocking drainage. Depending on the ground, it can be laid either below the sub-base or just under the turf. Without it, you’ll be forever fighting weeds.
For a cost breakdown, read our artificial grass pricing guide.
Should You Use Sand Under Artificial Grass?
Yes, but the right kind:
- Sharp sand – easy to screed, decent drainage, budget-friendly.
- Grano dust – sets almost like concrete, excellent for drainage, holds up better to dogs.
- Limestone fines – free-draining and easy to work with.
Avoid soft builders’ sand – it shifts, holds water, and can cause dips.
For dog owners, our dog-friendly artificial grass is designed with drainage and odour control in mind.
How to Prepare the Ground in the UK
If you’re laying on soil, here’s the typical process we follow:
- Excavate — remove turf/soil down to about 75 mm.
- Edge the area — timber or concrete edging to secure the lawn.
- Add MOT Type 1 — compact in 2–3 layers to 50–60 mm depth.
- Lay sand/grano — 10–15 mm for levelling. Compact and screed smooth.
- Install weed membrane — cut and pin into place.
- Lay your grass — secure joins, fix edges, brush pile upright.
Looking for a trusted local team? See our Artificial Grass Bury page.
Extra Layers for Dogs & Play Areas
If your garden is home to dogs or kids, a few extra layers will make a big difference to comfort, hygiene, and longevity:
- Free-drainage foam underlay – adds softness underfoot and protects against knocks and falls.
- Polyurethane-backed turf – resists urine damage and prevents lingering odours.
- Zeolite infill – a natural mineral that neutralises ammonia in dog urine and keeps turf smelling fresh.
- Sand or silica infill – helps add weight, prevent wrinkles, and keep fibres upright.
Our dog-friendly artificial grass installations use these features to create a clean, safe play space that stands up to daily use.
Regional Ground Conditions in the UK
Ground prep isn’t one-size-fits-all. In the North West, clay-heavy soils often hold water and need a deeper MOT sub-base for proper drainage. In sandy or free-draining soils (common in parts of the South and coastal areas), the base depth can sometimes be reduced — though we still recommend a full MOT + sharp sand layer for the best results.
Factoring in your local ground type ensures your lawn drains properly all year, without dips or waterlogging.
FAQs About What to Put Under Artificial Grass
Still wondering whether you need sand, a membrane, or a full sub-base? You’re not the only one. These are the most common questions homeowners ask us about what goes under artificial grass — with straight, practical answers from our installation team.
Do I need anything under fake grass?
Yes – MOT base, sand layer, and weed membrane at minimum.
What’s the best sub-base for dogs?
MOT Type 1 with a grano dust top layer plus polyurethane-backed grass.
Does mould grow under fake grass?
Only if drainage is poor. A free-draining base prevents it.
What’s the cheapest way to lay artificial grass?
DIY with compacted soil and sharp sand, but it won’t last as long as a full MOT + sand base.
How long does it take to settle?
24–48 hours – brush the pile upright and allow it to bed in.
How long does it last with proper prep?
10–15 years is normal with correct groundwork and light maintenance.
Do you need underlay for artificial grass?
Only on hard surfaces like concrete, patios, or decking. In these cases, a foam underlay adds comfort and helps with drainage. For soil-based installs, you don’t need a separate underlay – just MOT base, sand, and membrane.
What sand do you use under artificial grass?
Always use sharp sand, grano dust, or limestone fines. Avoid soft builders’ sand, which shifts, holds water, and can lead to dips.
Can weeds grow within artificial grass?
Not if it’s installed correctly with a permeable weed membrane. Occasionally airborne seeds can sprout on the surface, but they’re easy to pull out and don’t damage the turf.
Want it done once, done right? What goes under your artificial grass decides how long it lasts. We’ll handle excavation, base, drainage and the perfect finish. Request your free survey and let our team handle the groundwork.
