How to cut paving slabs: three ways to get a precise finish

Knowing how to cut paving slabs is essential to getting a crisp, clean finish. It’s a relatively simple DIY job, but you really need to have the right tools and some necessary know-how, which you can find in this guide.

You might have great patio ideas lurking in your head or on paper, but to make sure it looks like you imagine you need to choose the right technique and tools to do the job, or alternatively call out a professional. 

Here we take a look at a basic hand powered technique alongside a power tool technique and tell you how it's done.

How to cut paving slabs: what are my options?  

There are effectively two options when cutting paving slabs for laying a patio: cut by hand or cut with a power tool. The basic – and cheaper – option is too cut with a hammer and chisel. But this doesn’t offer the crisp, clean cuts you would get with a power tool. So you need to decide which is the best option for the job you are taking on.  

Whatever option you choose, make sure that you have the right protective gear. At the very least you need a pair of safety goggles to protect your eyes from shards of concrete or stone that may splinter off the slab. A pair of protective gloves is not as essential but still a useful addition especially if you are doing a lot of cutting.

Cutting paving slabs with a hammer and chisel 

For this technique you will need a lump hammer, a chisel and a rubber mallet to complete the job. This method isn’t ideal if you need a sharp, clean edge but will work well if you are working on patio edging ideas.

1. Measure and mark

The first step is to measure the gap you have from the edge of the last full slab to the edge of the space you need to fill, typically the edge of the patio. Measure the gap on both the left and right edge of the slab. This helps give a more accurate cut. 

Now mark the two measurements – one on the left and one on the right – on the slab to cut and use a straight edge such as a spirit level to join the two marks together and ensure you get a straight line.

2. Cut the patio slab

For the next step you'll need a lump hammer and a cold chisel or bolster chisel like the OX Trade Brick Bolster with Guard from Amazon. Make sure that the patio slab is placed on an even and secure surface.    

Place the chisel just outside the line you made and hit with the hammer. Move along the line and repeat until you have a 1mm or 2mm deep cut. Depending on the depth of the slab, the slab may break or not. If not, use a rubber mallet and hit the side of the slab you are not using. If needed, create a deeper cut with the hammer and chisel. 

Once cut, clean up the edge with the chisel.  

Cutting paving slabs with a power saw

For this option you will need a power saw like the Evolution 230mm Concrete Saw with a diamond-tipped blade suitable for cutting through masonry. 

1. Mark the cut line

First thing you need to do is get out your tape measure and mark where you need the cut with chalk or a pencil. Use a long straight edge to mark the top and bottom of the paving slab to be cut.

2. Secure and cut paving slab

Ideally you want to secure the slab on a workbench with clamps. But if this isn’t possible, place it on a solid, secure surface with towels or a foam mat under the slab. Before you start, wet the slab to help keep down the dust levels.

Start by making a deep cut along the line on one edge and then the other edge. Now go from one side to the other, gradually cutting through the slab until the cut is complete.

If you have a thick slab, you might need to turn over the slab and cut from the other side until you reach the top cut.

How do you achieve a straight line when cutting a paving slab?

The first thing to do is measure up and create a straight line with a pencil or chalk, using a straight edge that is longer than the cut to mark the line. 

If using a power saw, place the slab on a level surface with a thick towel underneath to hold in place and absorb vibrations.

Line up the blade and create a shallow cut along the line and wipe away any dust and debris. Now start on one edge and create a cut that is around 3 inches long and goes all the way through the slab. Use a subtle sweeping motion going back and forth to ensure a clean cut. Repeat at the other end of the slab. 

You now have two top to bottom cuts on both edges of the slab. This helps ensure that you get a clean, straight cut, and if the slab does break it should still be a straight break. Now cut the remaining slab along the line.

Once your patio slabs are cut and in place it's all about pointing patios to get that final finish. 

How to cut patio slabs with a block and slab splitter 

The pros use a tool known as a block and slab splitter. These are an ideal choice if you have dense paving slabs or stones and also work well with concrete paving slabs. 

These are far more expensive to buy than the other options, but luckily you can hire one for a reasonable price. Daily rates are typically around £40 a day and a little more for a weekend.

They are easy to use. Simply place on a sturdy flat surface, mark out your cut with chalk and place the slab in the machine in line with the cutting blades of the slab splitter. To make the cut, pull down the lever and it will cut the slab from above and below. 

Can you use an angle grinder to cut paving slabs? 

Yes you can. An angle grinder is a popular choice for cutting paving slabs as they are relatively cheap to buy, versatile and simple to use. Like other powered cutting tools you will need the right blade to cut through a paving slab. A diamond blade like the GRAFF Diamond Disc found at Amazon is a good choice. 

Make sure to wear safety goggles and a dust mask as an angle grinder can throw up a lot of debris and dust.   

What's the best tool for cutting paving slabs? 

This depends on what type of paving slab or stone you are using and how fine a finish you are looking for. But, as a general rule the best tool for cutting paving slabs is a power saw equipped with a diamond blade. This gives cleaner and more precise cuts and is ideal for porcelain paving, granite paving and concrete paving slabs