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.
What goes under artificial grass matters just as much as the turf itself. The right base keeps the surface stable, helps water drain away properly, reduces the risk of weeds, and stops the lawn from feeling uneven or spongy over time.
For most soil-based garden installs in the UK, the best setup is a compacted MOT Type 1 sub-base, a thin levelling layer of sharp sand or grano dust, and a permeable weed membrane. On hard surfaces like concrete, patios, or decking, the better option is usually a drainage underlay or foam pad rather than a full stone base.
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 put under artificial grass, whether you’re planning a DIY installation or booking 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 Base for Artificial Grass?
The best base for artificial grass depends on what surface you are installing onto. For most soil-based UK gardens, the most reliable option is a compacted sub-base of MOT Type 1 topped with a thin levelling layer of sharp sand, grano dust, or limestone fines. If you are laying artificial grass on concrete or decking, a drainage underlay is usually more appropriate.
For most domestic gardens, this is 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 |
Artificial Grass Base Layers Explained
If you are wondering what the full build-up looks like, most soil-based installations follow the same basic layer structure from bottom to top:
- Excavated ground – existing turf, soil, roots, and loose material removed
- MOT Type 1 sub-base – compacted to create a stable, free-draining foundation
- Sharp sand, grano dust, or limestone fines – a thin screeded layer for levelling
- Permeable weed membrane – helps suppress weed growth without trapping water
- Artificial grass – laid, joined, secured, and brushed up
On concrete, patios, or decking, the layers are usually simpler: a clean solid surface, a drainage underlay if needed, then the artificial grass itself.
Do I Need a Weed Membrane Under Artificial Grass?
In most cases, yes. A permeable weed membrane helps stop weeds pushing up through the installation while still allowing water to drain through the base properly.
It is especially useful on soil-based garden installs where roots, seeds, and organic matter are more likely to cause problems over time. Depending on the build-up, the membrane may be installed beneath the sub-base or directly under the turf layer.
For a cost breakdown, read our artificial grass pricing guide.
Should You Use Sand Under Artificial Grass?
Yes, but only the right type and only as part of the correct build-up. Sand is usually used as a thin levelling layer above the compacted sub-base, not as the main foundation itself.
- Sharp sand – easy to screed, reasonably free-draining, and widely used on domestic installs
- Grano dust – firmer and often preferred where a tighter finish is needed, especially in dog-friendly gardens
- Limestone fines – another workable levelling option with good drainage
Avoid soft builders’ sand because it shifts too easily, holds more moisture, and can lead to dips or instability under the grass.
For dog owners, our dog-friendly artificial grass is designed with drainage and odour control in mind.
What About Concrete or Decking?
If you are laying artificial grass on concrete, patios, balconies, or decking, you usually do not need a full stone sub-base. Instead, the focus is on drainage, comfort, and smoothing out minor imperfections in the surface underneath.
In these cases, a foam underlay or drainage underlay is often the best option. It can:
- Improve comfort underfoot
- Help the grass sit more evenly
- Assist with drainage on hard surfaces
- Mask minor cracks, ridges, or joins
If the concrete already drains well and is in good condition, underlay may not always be essential. But on hard, unforgiving surfaces, it usually makes the finished lawn feel and perform better.
How to Prepare the Ground for Artificial Grass 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 used heavily by dogs or children, the base and supporting layers matter even more. The best artificial grass base for dogs needs to drain quickly, stay stable, and cope well with repeated cleaning.
These extra layers and product choices can make a big difference to comfort, hygiene, and long-term performance:
- 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, underlay, a membrane, or a full sub-base? These are some of the most common questions homeowners ask us about what goes under artificial grass.
What goes under artificial grass in most UK gardens?
For most soil-based gardens, the standard build-up is a compacted MOT Type 1 sub-base, a thin levelling layer of sharp sand or grano dust, and a permeable weed membrane beneath the artificial grass.
Do you need underlay for artificial grass?
Usually only on hard surfaces like concrete, patios, or decking. In those cases, a foam or drainage underlay can improve comfort, drainage, and the finished feel. On soil-based installs, you normally do not need a separate underlay.
What is the best sub-base for artificial grass?
For most domestic gardens, MOT Type 1 is the best all-round choice because it compacts firmly, supports drainage, and creates a stable long-term base.
What is the best base for artificial grass with dogs?
A compacted MOT Type 1 base with a firm top layer such as grano dust is often the best option for dog-friendly gardens, especially when paired with a turf designed for drainage and easy cleaning.
What sand do you use under artificial grass?
Use sharp sand, grano dust, or limestone fines. Avoid soft builders’ sand because it shifts too easily, holds more moisture, and can contribute to dips.
Do you need a weed membrane under artificial grass?
In most cases, yes. A permeable weed membrane helps suppress weed growth without trapping water in the base.
Can weeds grow through artificial grass?
Not usually if the lawn is installed correctly with a proper membrane and base. You may still get occasional surface weeds from airborne seeds, but these are easy to remove and do not usually come up through the full build-up.
What is the cheapest way to lay artificial grass?
The cheapest option is usually a simpler DIY install, but cutting corners on the sub-base often leads to a shorter lifespan, uneven areas, and drainage problems later on.
How long does artificial grass last with proper preparation?
With the correct groundwork and routine maintenance, a good-quality artificial lawn will often last 10 to 15 years or more.
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.
