Everything You Need to Know About Installing a Laying Course for an Artificial Lawn

Everything You Need to Know About Installing a Laying Course for an Artificial Lawn


granite dust laying course

We’re frequently asked a whole host of questions surrounding laying course installation, so we decided to dedicate an entire blog post to the subject.

In this article we’ve hopefully answered many of the burning questions you have when it comes to installing the laying course for your artificial lawn.

Correctly installing an adequate laying course is fundamental to success, when it comes to long-lasting artificial turf.

It is a vital part of the installation process; you can have the best artificial grass that money can buy, but if you don’t get the laying course right, it won’t perform as it should.

It will also make a big difference to how your finished lawn will look, as an uneven or poorly compacted laying course will result in a lumpy looking fake lawn.

So, let’s start by first explaining, for those who don’t know, exactly what a laying course is.



What is a laying course?


Within the artificial grass industry, what is known as the ‘laying course’ is the final layer of aggregates that is installed directly underneath the artificial grass, and on top of the sub-base.



Why should you install a laying course?


The purpose of the laying course is to provide a flat, smooth surface on which to lay your fake turf.

Prior to installing the laying course, you’ll need to install a 50mm–100mm sub-base, consisting of either MOT Type 1 or granite chippings.

You cannot lay artificial turf directly on top of the sub-base material, as it would not provide a smooth, flat finish to the turf.



What should the laying course consist of?


Granite Dust Laying Course

Granite Dust Laying Course

For the laying course, we recommend that you use either limestone or granite dust, which is sometimes known as ‘grano’ – short for ‘granolithic’.

This dust, or grano, is 0–6mm in diameter.



What depth should a laying course be?


We recommend that you install your laying course to a depth of 25mm, or 1 inch.



How much aggregate will I need for the laying course?


Granite or limestone dust is typically supplied in ‘bulk bags’, or ‘ton bags’, as they are also known.

Contrary to their name, ton bags typically weigh around 850kg, rather than a ton, so please ask your supplier for the approximate weight of the bulk bags prior to purchasing to ensure you order the correct quantities.

To help you calculate how much you need, enter the total square meterage of your lawn area in the calculator, below.



Where can I get hold of granite or limestone dust?


You can normally buy it from your local aggregate supplier, builders’ merchant or DIY store.

Depending on where in the UK you are based, you may find that granite is easier and/or cheaper to source than limestone, or vice versa.

We recommend that you choose whichever is most cost-effective locally, as both forms of aggregate are equally suitable.



Can you use sharp or building sand as a laying course?


We do not recommend that you use any type of sand to form the laying course.

Several years ago, using sharp sand was the standard procedure for many artificial grass installers. However, sharp sand will lose its compaction over time, causing it to move underfoot.

Bear in mind that there are perforations in the backing of artificial turf, to allow rainfall to drain through, and this can cause the sand to gradually wash away, too.

Granite or limestone dust is a coarser material that binds together far better than sand, thereby providing a stronger, more resilient laying course.



How do you level the laying course?


The laying course is levelled using a rake, to a depth of 25mm (1 inch) across the entire lawn area, and then thoroughly compacted.



How do you compact the laying course?


Virbating Plate Compactor (whacker plate)

A granite dust laying course being compacted with a vibrating plate compactor

The laying course should be compacted using a vibrating plate compactor, which can be hired from your local tool hire shop.

To ensure adequate compaction, guide the plate compactor both up and down, and from side to side, across the entire surface of your lawn.

Prior to using the plate compactor, we recommend that you lightly spray the aggregates using a garden hose. This helps the dust bind together, whilst also helping to prevent the dust becoming airborne.

For further information on compaction, please see ‘The Importance of Adequate Compaction When Installing an Artificial Lawn’.



How do you compact the laying course in small areas, such as between two stepping stones, where a vibrating plate compactor can’t fit?


For areas that the plate compactor will not reach, such as between stepping stones, narrow strips of turf or tight corners, we recommend that you compact the aggregates using a hand tamp.



Should there be anything underneath the laying course?


Edging & Sub-Base

Granite chipping sub base with treated timber edging

Yes. A sub-base consisting of either MOT Type 1 or, if you have drainage issues, 20mm granite or limestone chippings should be installed, both to a depth of 50mm–100mm, depending upon the expected volume of foot traffic.



What should I use to retain the laying course?


When installing artificial grass, it is very important to have an edge restraint in place.

The edge restraint will retain the aggregates and prevent them from collapsing at the sides of your lawn.

The edging may also provide something to secure the perimeter of your lawn to.

For further information on the types of edging system you can use, and how to secure the perimeter of your artificial lawn, please see ‘6 Types of Edging System for Artificial Grass’.



Should I place a weed membrane on top of the laying course?


Weed Membrane Applid to Laying Course Prioer To Artificial Grass Installation

Yes. Although it’s not essential, we strongly recommend that you do so for two reasons. Firstly, it’s an extra line of defence against potential weed growth and secondly, it will help to protect the backing material of the fake grass.



I am installing a foam shockpad underlay; do I still need to install a laying course?


Yes. We recommend that you follow the standard installation procedures and lay your foam underlay on top of the laying course.

This is because the larger stones found in the sub-base material could potentially puncture the foam underlay.



Can you install a laying course over an existing surface, such as paving slabs?


Artificial Grass on Concrete - Step 4

Artificial grass installed on to existing block paving, using a 20mm foam underlay

It is possible to install artificial grass to existing surfaces such as concrete, paving slabs, block paving and decking.

However, in those instances, rather than installing a laying course, we generally recommend that you use either a 10mm or 20mm foam underlay.

The foam underlay will provide a sufficiently smooth surface to lay the grass on to. The foam will both provide a soft feel underfoot and cover up any undulations in the underlying surface – for example, the ridges in decking – which, without the presence of the foam, would be visible through the finished artificial lawn.



My lawn was installed several years ago; sharp sand was used for the laying course and it has now sunk in places. Can I just add a layer of granite dust on top of the existing sharp sand and then recompact it?


We recommend that you remove the existing sand entirely, and then add either granite or limestone dust to form the new laying course.

If the existing sand laying course was deeper than 25mm, we would recommend ‘topping up’ the existing sub-base with Type 1, to leave 25mm for the new granite/limestone laying course.





Installing an adequate laying course is a vital part of the artificial grass installation process.

Get it wrong and you may be disappointed both with how your finished lawn looks and the way in which it performs.

However, by following the advice laid out in this article, you should find that installing your own laying course is a breeze.

If, however, you are still not sure, you can contact us directly or leave us a comment below.

If you would prefer to use the services of a professional, then why not get in contact with your nearest NeoGrass Approved Installer? Our network of experienced installers will take care of the entire process, from start to finish, leaving you to sit back and enjoy the amazing transformation that takes place.

You can request your free samples from our range of artificial grass here.

Have we missed anything from this article? Do you have a burning question that we’ve not answered? Then why not leave us a comment below? We’ll gladly answer any queries you have and add your question to our article.

As always, thanks for reading.



15 Responses to “Everything You Need to Know About Installing a Laying Course for an Artificial Lawn”

  1. Annemarie Natarajan

    I am hoping to install a small Astro football pitch for my boys in the garden
    I have read about the subbase and laying course so would I need a 5 cm granite 10 to 12 mm subbase and a granite dust laying course plus the shock pad underlay …so overall I would need to dig to a depth of 9.5 cm approximately?
    I understand weed membrane is go on top of the subbase and on top of the laying course… even with a shock pad underlay?
    Please can you advise if this is correct thank you as I would like to order the shock pad underlay from you

  2. Michael King-Taylor

    Good morning. I’ve just read through this install guide which is brilliant, my question is regarding the “grano” dust. You state 0-6mm but I can only find 0-3mm in my area, will this allow drainage when compacted?

  3. Hi there, firstly your website is brilliant for information for us grass laying novices out there like myself, so thanks firstly for that!! I’m looking to install artificial grass over a paved/slabbed area with potential drainage issues. I plan to use granite/limestone chippings and 50 to potentially 75 mm sub base (due to the drainage issues) and then granite or limestone dust for the laying course. I also read that its recommended to wet the laying course before compaction to help with the compaction? What may seem a silly question, do I need to complete the sub-base/laying course to a slight ‘downhill’ for drainage, or will the aggregates do all that and the sub-base/laying course completed level to ensure a level lawn end product?! Am I to assume that the laying course will adhere or fix to the sub-base somehow to form one thick layer?! When it comes to fixing the grass, other than fixing/glueing the grass to the timber edging I propose to use, is the compacted laying course hard enough to be able to put glue on also to help with adhesion, or should this be avoided due to draining through the grass for water. My last question!…as I plan to use timber edging, am I best fixing this to the wall it is going against, or securing from the top down into the existing patio slabs? I would rather fix it to the wall! And what screws would I be best using given that they’ll be exposed to moisture. Many many thanks in advance!

    • Neo Grass

      Hi Michelle,
      Firstly, when you apply the sub base followed by the granite dust layer and ensure that both levels are compacted well, then this negates the need to slope the levels slightly, unless you know you have extremely poor drainage, then of course this would aid it.
      When it comes to fixing the edges you can use standard artificial grass pins which you can get on Amazon i believe at quite a good price. When fixing the edging it’s not a good idea to then glue anything down in the middle area.
      The wall would make a good strong structure for the timber edging.
      Kind regards,

  4. Hi, i’ve had my fair share of advice off you recently, but just a couple of things I’d appreciate your help on. Information advises of a 25mm laying course, can this be increased at all? I will be covering a drain cover and whilst I realise a laying course’s purpose is to make the surface smooth I was wondering if there would be any issues in increasing it to 38 mm to ensure sufficient clearance over the drain cover! (38 mm as this is the next size timber to 25 mm for the frame!! – if you recommend 25 mm then that’s no problem! Secondly, jointing tape, i’ve noticed this isn’t attached to the laying course, and most I have seen are self adhesive. Can I add glue to this for extra security when sticking the grass to it?…and lastly (!) i will be tacking the weed membrane to the wooden frame, however I would rather glue the grass to the wooden frame than pin it. The grass adhesives claim they have an excellent bond with wood, so is this a viable option considering the grass needs to be pulled slightly to be fix into place. Thanks in advance!

  5. I intend laying artificial grass over an area of slate crazy paving, the mortar between the slate has deteriated,can I just lay foam underlay 20mm or do I need sub base and to what depth?

    • Neo Grass

      Hi Matt,
      The problem with decorative chippings is that they probably won’t compact down very well.
      You need to bear in mind that you then need to apply a layer of Granit Dust or Grano as it is sometimes known and compact that down as well.
      Kind regards,

  6. Hi, I have just had a piece of astroturf laid (12x4mtrs). We used MOT as the sub base. For the laying course my builders merchant suggested 2-6mm lime dust. My gardens had problems compacting this to any sort of dust. They used water and spent time using a whacker. It still looked a bit like cat litter. Anyway, they laid the Astro turf on top. It’s a little crunchy when walking on it, but that got better after apply sand to the fake grass. It does feel quite solid under foot. Will it last? Thanks

  7. Hi, we are installing fake grass in our garden due to the dog wrecking the natural lawn with lawn burns. My questions is about the quality of the soil. After removing our turf it seems that the soil is more like clay and just will not dry out. Is this likely to cause problems to the finished fake lawn? The surround is a paved pathway around 3 sides and secured fencing around the 4th so it’s pretty solid but I just want to make sure it won’t affect the quality of the finish. Thanks.

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