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How To Choose The Correct Artificial Grass Sub Base Artificial Super Grass

How To Choose The Correct Artificial Grass Sub-Base

Go green with artificial grass in Halifax this summer, and reap the rewards of this low-maintenance landscaping solution that requires no watering, weeding, or mowing. It’s a lifestyle investment for private residences, commercial premises, schools, and new project development sites. And with our top tips on how to choose the correct artificial grass sub-base for soil, concrete, and decking installations, you could have your new lawn ready by the weekend.

Installing synthetic grass is easy with modern landscaping materials, and with the right foundations, a single installation could last 10-years or more. But what are the right foundations, and how do you know which ones are right for your artificial turf? In this complete guide, we’ll provide full details on the different types of sub-bases available, along with advice on choosing the perfect match for your lawn.

What Is An Artificial Grass Sub-Base?

So what is an artificial grass sub-base, and why do you need one? Well, firstly a sub-base is a layer of material that sits above the soil or subgrade to create a solid foundation for synthetic turf installation. Also referred to as aggregate, this base material prevents weed growth, improves drainage, and protects against any settlement, which can lead to an uneven surface.

A quality sub-base not only provides structural stability, but it helps bear the weight of heavy garden furniture, so it is essential to have one when installing imitation grass on a malleable surface. See it as the foundations of a house. It is the groundworks of your new garden, and as such, you should invest in the best you can find.

Types Of Artificial Grass Sub-Base Available

Here is an overview of the most common types of aggregate used in artificial grass installation in the UK. If you are not sure which one is right for your garden, speak to your local landscaping professionals, who will be able to provide further guidance on the best sub-base for any terrain.

Compacted Ash

Compacted ash, also referred to as fly ash and bottom ash is a popular sub-base for artificial grass installations due to its excellent drainage properties. Commonly used in construction projects and highway maintenance as an alternative to earth or sand, it is a sustainable aggregate that is both cost-effective and exceptionally durable.

Compacted ash is ideal for synthetic grass installations on top of natural soil. It spreads with ease, it provides a superior level of stability, and a single application will last the lifetime of your artificial lawn.


MOT Type 1 Aggregate (Crushed Stone or Concrete)

Approved by the Ministry of Transport for the construction of roads and pavements, MOT Type 1 Aggregate is a crushed stone sub-base, made from various materials including limestone, granite, and concrete. It is one of the most robust foundations you can use for artificial grass installation, which is perhaps why it remains the most popular aggregate used in construction and engineering in the UK. But it is not suitable for all gardens.

MOT Type 1 is technically a non-porous sub-base, and so if you have drainage issues, or you have dogs that like to pee in your garden, it’s probably not the best choice for you. In this instance, we would recommend using a crushed stone aggregate made from limestone or granite chippings, which are slightly larger and allow improved drainage.

Granite Dust, Limestone Dust, and Sharp Sand

If you decide to use a crushed stone sub-base, you’ll need to use a top layer of granite dust, limestone dust, or sharp sand to create a smooth surface for installation. These fine-materials fill in the gaps between the sub-base, so you should look at using a top layer of around 15-20mm, and compacting it with a vibrating plate or heavy-duty roller.

The compacted sand/dust should sit level with any artificial grass edging you have used and must be completely smooth before you apply the second layer of weed membrane. Use too much or too little, and you’ll have lumps and bumps in your lawn, so leave it to settle for a few hours before securing the weed membrane, and go over it again with the roller if necessary.

Crushed stone, MOT Type 1, dust, and sharp sand sub-bases are suitable for all soil installations.

Foam Shock Pad Underlay

If you intend to install artificial grass on concrete, wooden decking, or a sound, existing surface such as paving, you won’t need an aggregate sub-base but, you will need a foam shock pad underlay to create a smooth, cushioned surface. This is especially important when you are installing imitation grass on children’s playgrounds or sports surfaces that need to comply with EN 1177:2008 safety standards and Head Impact Criteria (HIC).

As the name suggests, foam shock pad is a spongy underlay that creates a smooth, level surface on solid foundations. Made from perforated polyethene bonded foam, a 100% recyclable, environmentally friendly material, it comes in a choice of thicknesses to suit all landscapes.

Designed for fake grass installations; foam shock pad underlay is permeable and offers excellent drainage properties. It’s ideal for masking undulations in wooden decking and paving stones, and as it is non-absorbent, it doesn’t retain unpleasant odours. A single installation will last the lifetime of your synthetic lawn and put a spring in every step.

You can use foam shock pad underlay with an aggregate sub-base, but you should apply it on top of the second layer of weed membrane, to prevent damage from sharp stones or sand. It will sit nicely underneath your synthetic turf to cushion the impact of any trips and falls, so it’s ideal for family gardens.

Artificial Grass Sub-Base FAQs

If you haven’t found the answers to your sub-base questions above, you may find them below in our most popular FAQs.

Do I Need A Sub-Base For My Artificial Lawn?

If you are replacing real grass with synthetic turf, then yes, you need a sub-base to create solid foundations for your new lawn. You cannot install fake grass directly on top of ground soil. You do not necessarily need a sub-base if you are installing imitation grass on a structurally sound surface such as concrete but, a foam underlay will cover any imperfections and undulations while creating a softer surface underfoot.

How Much Sub-Base Do I Need?

We recommend installing a sub-base of around 70mm deep for domestic installations. Possibly more, up to 100mm for school playgrounds and commercial landscapes. To calculate how much you need, use an online calculator or contact your local artificial grass supplier for advice.

Which Sub-Base Is Best For Soil Applications?

We believe that compacted ash is the best sub-base for soil applications. It offers superior drainage to MOT Type 1 and Crushed Stone aggregates, and it is relatively inexpensive when compared to some of the alternatives. It creates a smooth foundation for artificial grass application, and will easily last as long as your lawn.

How Do I Level Sub-Base Materials?

The easiest way to level a sub-base material is with a rake, before compacting it with a heavy-duty roller or vibrating plate compactor. You can hire these from your local tool hire shop. Tying to install synthetic turf on an uneven surface will create all kinds of problems, and by renting the right materials for the job, you’ll save a great deal of time.

Do I Still Need A Sub-Base When Installing A Foam Shock Pad?

This depends on the type of surface that you are installing it on. If you are replacing your existing lawn with fake grass, then yes, you will still need a sub-base, but if you are installing it on a stable, solid surface, then no, you will not.

Where Can I Buy Artificial Grass Sub-Base Materials?

If you are having your synthetic lawn installed by a team of professionals, then they will provide the sub-base materials and include them in the total cost of installation. If you are laying your astroturf yourself, you can buy your sub-base materials at any aggregate supplier. Ask your artificial grass supplier for a recommendation in your local area.

How Much Do Synthetic Turf Sub-Base Materials Cost?

This all depends on the size of the area you are landscaping, the depth of your sub-base, and the type of material that you choose. As a rough guide, an 800kg bag of MOT type 1 or coarse sand will set you back between £40 and £50, while foam shock pad underlay can cost anywhere between £10 and £30 per square metre, depending on the thickness you choose.

For more information on artificial grass sub-base creation, speak to your friendly local installers at Artificial Super Grass, and together we’ll transform your garden into an evergreen oasis that you can use all year round.

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