How to install the groundworks for an artificial grass lawn
By Gavin Hall
Professionally installed artificial grass groundworks
Having chosen a high quality artificial grass I will now walk you through how to install the groundworks for an artificial grass lawn
You have performed the difficult task of choosing the perfect artificial grass for your lawn from the hundreds available on the market. I will now give you a step-by-step guide on how to install a perfectly level artificial grass lawn that drains well and is free from weeds. This guide is a little more technical than other blogs I have written and may require some extra manpower but see it through to the end and you will get a long lasting, great looking artificial grass lawn.
To prepare your groundwork’s here is a shopping list of items that you will need:
- A Wacker plate
- Turf lifter or spade
- Mot Type 1 aggregate
- Granite dust
- A screeding tool (3″ x 2″ timber cut to 1.5 metres long)
- Cement and ballast for the concrete
- Bricklaying trowel
- Wheelbarrow or concrete mixer
- 3″ x 2″ timbers
- 4″ x 2″ timbers if laying on a slope
- A rake
- Thick weed membrane
- Padding for knees
- Spirit level
- Measuring tape
- Shovel for moving the aggregate
- Timber baton for pegging timbers in place
- Hammer and 4″ nails for fixing membrane
- A skip
- A stiff brush to clear up
…and a friend or two’s help
Assess the area and your requirements
Take a look at the area where you want to install the artificial grass and ask yourself these questions:
What is the current drainage like?
If there is a boggy area which is prone to puddles you will need to improve your irrigation. The best way to do this is to dig a pit 2 to 3m² and fill it with rubble. These pits are often called soakaways and are fine for lawns with minor drainage problems. If you have a major drainage issue in your garden I suggest you call in a drainage expert and install something like a large sunken tank.
Is there a severe slope in your garden you want to flatten out?
If this is the case I will position some 4″ x 2″ timbers (set in concrete) at the top of the slope which I will later fix the artificial grass to it so it can’t slide or add a small retaining edge ie railway sleepers so it can be slightly raised at one end to reduce the slope. Here I have written an indepth article on fitting artificial grass on a slope.
Do you have a bad weed problem?
This should be addressed weeks before by using a systemic weed killer like Round-up to reduce the issue. If you do not eliminate the weeds at an early stage, weeds and real grass will eventually grow through the artificial grass. We have found that doing this reduces weeds by approximately 90%.
How much Type 1 aggregate will I need for the job?
As a rule of thumb the way I calculate how much aggregate I need: 7sqm = 1 tonne at 2 inches. If the lawn has particularly poor drainage I will double the depth of aggregate.
How much Granite dust will I need for the job?
To calculate how much I need: 14sqm = 1 tonne at 1 inch.
How much timber will I require for the perimeter of the artificial grass lawn?
I simply measure the distance around the perimeter with a measuring tape.
Clear the ground
To have nice clean, smooth foundations on which to lay your artificial grass remove the turf, soil, vegetation and any large rocks or stones until you reach your natural sub base. This will generally require between 0 and 6 inches of excavation depending on your location. You will know when you have reached your substrate as the ground will be firm when you stand on it. A turf lifter can be hired for the day to speed this step up or now is the time to recruit a friend or two with large shovels!
… Relax with a nice cup of tea before moving on to the next step.
Install the perimeter fixings
Once the area is clear you will need to lay 3×2 timber fixings around the perimeter of the new artificial lawn. To secure them I dig a trench a little wider than the timber. I then add concrete to the trench and set the timbers in it. Remember the more concrete you use the longer the life of the timber however, you can now buy plastic timber, which will last forever but it is five times more expensive than wood! The timber needs to sit just below the level you wish the grass to be cut to.
… and another cup of tea maybe with a digestive
Prepare the sub-base
Add 2 to 4 inches of Mot Type1 aggregate
Just like in the preparation of roads professionally installed artificial grass requires a good sub-base so that the grass remains nice and flat. I start by either using a 2-inch layer of Mot type1 aggregate (crushed stone) to a depth of 2 inches or 10mm granite chippings (both of which can be purchased from your local builders merchant or garden centre).
I then make sure the aggregate is evenly spread and compact it with a Wacker plate (can be hired daily from an equipment hire shop) to just below the perimeter timbers.
Add 1 inch of Granite Dust
Next I add 1 inch of granite dust which I compact and level. Granite dust is a great product to use as it bings together beautifully when slightly damp. It then goes rock hard once dry but still allows water through. (Sharp sand is an alternative if you can’t get your hands on granite dust but it doesn’t bond as well). A quick self-promotion: I was the first person in the UK to use granite dust.
Screed the area
I now get down on my hands and knees and with a piece of timber screed the whole area to make it as smooth as possible. I work around the edge so the base it completely level with the timbers and drag the sand back making sure it is left in a nice hard but smooth shape. I generally go in semi circular motions. The reason you want to screed is because the artificial grass will mirror what is beneath it. You have lumpy groundworks and your artificial lawn will be the same.
Install a weed barrier
You don’t want grass and weeds growing through your artificial grass. To prevent this I add a thick weed membrane once I have cleared the soil ,so it is out of the way and under the aggregate. If the lawn owners have dogs it is an absolute must for the weed membrane to be under the aggregate to prevent the urine trapping on the top. There are other actions I take if the owners have dogs and want to make sure there is no urine odour issues in the summer months.
Always make sure to take the membrane right to the edge of the lawn. I use galvanised nails to fix it in place.
Hopefully by following my guide you will now know how to install the groundworks for an artificial lawn. I can’t stress enough the longer you spend on the ground works the better your artificial grass lawn will look.
In my next Blog post I will give you a guide on how to professionally fit the artificial grass on to your prepared ground works.
Need help with installing your artificial grass lawn or for a no obligation quote please call me Gavin Hall on 020 81664168 or fill out this form for your free sample