How to prepare the base for paving

Here is a short guide to the groundwork before you lay paving. It is very important to build a proper base with gravel and sand before you finally lay your concrete or granite paving slabs.

If the base is not good, the paving can sink and end up uneven. That is why it is essential to build a proper base for paving, so your paving looks good for many years.

Groundwork before building the base

The first and very important step is to assess your project based on the following questions:

How many kilos must your new paving be able to withstand?
Will only people walk on the paving?
Will cars drive on the paving?
Must it be able to withstand lorries driving on your paving?

The load that the paving – and therefore also the base – must be able to withstand determines how much road base is needed underneath.

Here is an explanation of 3 types of base for paving:

The first base for paving is the least durable. This type is good for terraces or footpaths, where only people, prams and wheelbarrows will put weight on your paving. Here we recommend a total base of 10 cm. You will need 6-7 cm of road base and 6-7 cm of paving sand / paving gravel. The reason you need a little more than 5 cm of each is that both the road base and the gravel on top will be compacted when tamped with a plate compactor.
The medium base is the one that can withstand ordinary cars, car trailers and caravans. Here you need a total base of 20 cm. You will use approx. 17 cm of road base and 6-7 cm of paving gravel or paving sand.
The last and most durable base for paving is 30 cm in total. This is the type you need if lorries may drive over the paving, or if you simply want the best base that you can be sure will hold whatever the load. Here you need approx. 28 cm of road base and 6-7 cm of paving sand or paving gravel on top.

So you need to dig out the area for your paving according to which base you choose.

Building a base for paving

When you have found the base that best suits your project, dig out accordingly. Remember to include the thickness of the paving slab itself.
In other words, if you need a 20 cm base and your slab is 7 cm thick, you must dig out 27 cm before you can start building the base.

First, spread the road base and compact it several times with a plate compactor. For a 10 cm base for a terrace or footpath, a smaller plate compactor of 40-70 kg is fine.
If, on the other hand, you are building the base for a driveway, we recommend getting a larger plate compactor that can compact it properly.

When the road base has been spread and compacted well, you can spread sand or gravel on top. This is spread and compacted well.
Finally, screed the sand / paving gravel so that the paving can be laid in it.

Remember to screed it so that it is completely level and has a fall in the right direction, so your paving can drain rainwater the right way.

Good luck with your project.