Everything You Need to Know About Installing a Laying Course for an Artificial Lawn
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?
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?
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?
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?
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?
It is possible to install artificial grass to existing surfaces such as concrete, paving slabs, block paving and decking.
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.