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Cutting porcelain paving slabs: which saw and which diamond blade?
Porcelain paving slabs are hard and usually 20 mm thick. You get the neatest cut with a water-cooled wet tile saw and a diamond blade made for porcelain or ceramic. For one-off cuts, curves and cut-outs, use an angle grinder with a diamond disc for porcelain or ceramic, preferably cutting wet and always with dust protection.
What will you learn in this article?
- What do you use to cut porcelain paving?
- Which diamond blade should you choose for porcelain?
- Step-by-step: cutting porcelain paving
- How to prevent chipping
- Cutting mitres and cut-outs
- Safety: silica dust and wet cutting
- Laying porcelain paving: get the base right
- Frequently asked questions about cutting porcelain paving
- In short: cutting porcelain paving
What do you use to cut porcelain paving?
| Tool | Good for | Advantages | Disadvantages |
|---|---|---|---|
| Wet tile saw (bench saw) | Straight cuts and mitres in lots of slabs | Clean cuts, little dust, cools the blade | Bulky, needs water and power |
| Angle grinder with diamond disc | One-off cuts, curves, cut-outs | Flexible, can be used in place | More dust, less precise |
| Manual tile cutter | Straight cuts, only if the model is rated for thick porcelain | Quiet, no dust | Not every model can handle 20 mm porcelain |
| Block splitter or bolster | Not suitable | Not applicable | Porcelain splits unpredictably |
For a whole patio, a wet tile saw is the most comfortable option, and you can often hire one from a tool hire shop. For a few cuts or infill pieces, an angle grinder is enough. A cordless angle grinder, for example from the Maxxpack 18V range, is then handy in the garden without an extension lead. Check the specifications of the grinder for its disc diameter and cutting depth. With a 125 mm angle grinder you can usually cut through a 20 mm slab in one pass, but it is neater to work in two passes.
Which diamond blade should you choose for porcelain?
Always use a diamond blade that the manufacturer specifies for porcelain, ceramic or tiles. A blade for concrete or block paving cuts too coarsely and makes the glazed top surface chip.
- Continuous rim: the best choice for porcelain. Gives the smoothest cut with the least chipping.
- Turbo rim: cuts faster, but slightly rougher. Fine for cuts that will be hidden under an edging or border.
- Segmented rim: designed for concrete and brick, not for porcelain slabs.
Also check whether the blade is suitable for wet or dry cutting, and that the bore size and diameter fit your machine.
Step-by-step: cutting porcelain paving
Using a wet tile saw
- Set the machine up level on a firm surface and fill the water tray.
- Plug the machine into a socket protected by an RCD. Water and electricity together call for extra care.
- Mark the cutting line on the slab with a pencil or marker.
- Place the slab face up on the sliding table and lock the fence.
- First cut a few centimetres in from both ends of the line. This stops the last bit from breaking off and the corner from chipping.
- Then make the full cut steadily. Feed the slab or the cutting head through the blade without forcing it.
- Rinse the slab with clean water so the slurry does not dry onto the surface.
Using an angle grinder
- Lay the slab flat and stable, for example on a sheet of insulation board or on two battens.
- Put masking tape along the cutting line and mark the line on the tape. This reduces chipping.
- First cut a shallow groove along the whole line.
- Then cut deeper in a second pass.
- Hold the grinder with both hands and keep the guard fitted.
- Smooth the cut edge with a sanding block or diamond hand pad if it is sharp.
How to prevent chipping
- Use a continuous rim blade made for porcelain.
- Let the blade reach full speed before it touches the slab.
- Cut from the glazed top surface down to the underside.
- Take care with the first and last part of the cut, or cut in from both ends.
- Replace a blunt blade. A blunt blade starts pushing and makes the edge break away.
Cutting mitres and cut-outs
For a mitre, for example on a step or low wall, you need a wet tile saw with a tilting head or table. Set the angle, make a test cut on an offcut and check that the angle is right.
Make a cut-out, for example around a drain or post, with an angle grinder. Cut the straight sides in up to the corners and form the curve with several short cuts. For round holes you can also use a diamond core drill bit for tiles.
Safety: silica dust and wet cutting
Porcelain contains crystalline silica. Dry cutting releases fine silica dust, which is harmful to your lungs. Stick to these rules:
- Cut wet wherever you can. Water binds the dust.
- If you have to cut dry, wear an FFP3 dust mask and work outdoors, with the wind behind you.
- Wear safety glasses, ear defenders and gloves.
- Keep bystanders and children well away.
- When cutting wet, always use an RCD and keep plugs and extension leads dry.
Laying porcelain paving: get the base right
Porcelain slabs are thin and hard. A poor base soon leads to cracked or loose slabs.
- Lay a stable, well-compacted sub-base using a plate compactor. Porcelain is often laid on a full bed of mortar, sometimes with a priming slurry on the back of the slab; follow the advice of the paving supplier.
- Fit edge restraints so the slabs cannot shift or sink.
- Use tile spacers for even joints.
- Do not run a plate compactor directly over porcelain slabs without a protective mat; check with the supplier whether this is allowed at all.
Frequently asked questions about cutting porcelain paving
Can I cut porcelain paving with an ordinary angle grinder?
Yes, with a diamond disc suitable for porcelain or ceramic. Work in two passes, cut wet if possible and wear an FFP3 dust mask. For lots of straight cuts, a wet tile saw is faster and neater.
Can I cut 20 mm porcelain with a manual tile cutter?
Only with a tile cutter that is specifically designed for it. Many standard tile cutters are made for thinner indoor tiles. Check the cutter's specifications for the thickness it can handle.
Should I hire or buy a tile saw?
For a single patio, hiring often makes sense. If you lay paving more often or work on several projects, your own machine can be worthwhile. Either way, get a good diamond blade for porcelain.
Why does my slab chip at the end of the cut?
The last part has less support and breaks off under the pressure of the blade. So first cut in a little from both ends, or support the slab well right to the end. A blunt or wrong blade makes it worse.
In short: cutting porcelain paving
Cut porcelain paving slabs with a water-cooled wet tile saw and a continuous rim diamond blade for porcelain. Use an angle grinder with a diamond disc for one-off cuts and cut-outs, work in two passes and cut wet where you can. Protect your lungs from silica dust and lay the slabs on a stable base with proper edge restraints.