What Is the Best Way to Cut 20 mm Porcelain Paving?
The cleanest and most controlled way to cut 20 mm porcelain paving is normally with a suitable wet bridge saw or wet tile saw fitted with a diamond blade specifically rated for thick porcelain. The slab should be fully supported, the blade allowed to cut at a controlled speed and water supplied continuously where the blade and machine are designed for wet cutting.
Can You Cut 20 mm Porcelain with an Angle Grinder?
Yes. An angle grinder fitted with a suitable porcelain-rated diamond blade can be used for shorter cuts, curves, notches and detailed work. However, it gives less guidance and support than a bridge saw, so long straight cuts generally require more skill and can show greater edge variation.
Do You Have to Wet-Cut 20 mm Porcelain?
Wet cutting is normally preferred for accurate repeated cuts because it cools the blade, suppresses dust and can improve cutting consistency, but specialised dry-cutting blades for 20 mm porcelain also exist. The blade and machine must always be used according to their manufacturer's wet- or dry-cutting specification.
What Blade Should Be Used for 20 mm Porcelain?
Use a high-quality diamond blade specifically designed and rated for thick porcelain or porcelain stoneware. Do not assume a general masonry or natural-stone blade will give an acceptable result. Blade design can include continuous-rim, turbo or specialist segmented configurations depending on the cutting machine and manufacturer.
How Do You Stop Porcelain Paving Chipping When Cutting?
Use the correct blade, support the complete slab, maintain a steady cutting speed and avoid forcing the blade through the material. Good machine alignment, adequate cooling where required and careful treatment of the blade exit edge also reduce chipping.
Cutting principle: 20 mm porcelain is much less tolerant of unsuitable tools than many paving stones. Blade specification, slab support and controlled cutting are more important than applying additional force.
Why Is 20 mm Porcelain Difficult to Cut?
Outdoor porcelain is fired to produce a dense, highly vitrified body with very low water absorption.
That density contributes to:
- high surface hardness;
- strong abrasion resistance;
- good outdoor durability;
- low water absorption.
However, those same characteristics make 20 mm porcelain paving demanding to cut.
The material is hard but also rigid. If the slab vibrates, the blade is unsuitable or too much pressure is applied, the cut can develop:
- edge chipping;
- broken corners;
- wandering cut lines;
- local cracking;
- excessive blade wear.
Best Tools for Cutting 20 mm Porcelain Paving
Wet Bridge Saw
A suitable wet bridge saw is normally the preferred tool for repeated straight cuts.
It provides:
- stable slab support;
- a guided cutting path;
- controlled blade movement;
- continuous water cooling;
- good repeatability;
- better control over long straight cuts.
This is particularly useful for large-format slabs such as 900 × 600 Porcelain Paving.
Angle Grinder
An angle grinder fitted with a porcelain-rated diamond blade is useful for:
- small straight cuts;
- notches;
- curved cuts;
- corner details;
- adjustments around drains and obstacles.
It is more portable than a bridge saw but less mechanically guided, so the installer controls alignment, depth and feed rate by hand.
For long exposed straight edges, a bridge saw will normally provide a more consistent result.
Track or Rail Saw
Some specialist rail-guided cutting systems are also designed for thick porcelain.
These provide greater portability than a large bridge saw while using a guide rail to improve straight-line accuracy.
The machine and blade must both be specifically suitable for 20 mm porcelain.
Choose the Correct Porcelain Diamond Blade
The blade is one of the most important parts of the cutting system.
Look for a blade specifically stated by the manufacturer to be suitable for:
- porcelain or porcelain stoneware;
- approximately 20 mm thickness;
- the intended machine;
- the required wet or dry cutting method.
Do not select a blade solely because it is labelled "diamond".
Diamond blades are manufactured for different materials and cutting characteristics. A blade intended for concrete, brick or general masonry may cut porcelain poorly even though both products use diamond abrasive.
Follow the blade specification. A wet-cutting blade should be used with the specified water supply. A blade specifically approved for dry cutting may be used dry where the machine and working method are also suitable.
Continuous-Rim vs Turbo or Segmented Porcelain Blades
There is no single blade geometry that is correct for every 20 mm porcelain cutting system.
Fine continuous-rim blades are commonly associated with controlled tile cutting because they can produce a clean edge.
However, modern specialist thick-porcelain blades can also use:
- turbo rims;
- very narrow segmented designs;
- specialised cooling slots;
- reinforced blade bodies.
The important distinction is therefore not simply "continuous good, segmented bad".
The correct question is whether the blade manufacturer specifically rates the product for thick porcelain and for the selected machine.
How to Make a Straight Cut in 20 mm Porcelain
Step 1: Measure Carefully
Measure the required cut from more than one point where necessary.
Include:
- joint width;
- edge detail;
- wall clearance;
- direction of the finished cut.
Check the measurement before cutting. A finished porcelain slab offers little opportunity to recover from a major measurement error.
Step 2: Mark the Cut Line
Use a visible waterproof marker, suitable wax pencil or another marking system compatible with wet cutting.
The line should remain clearly visible until the blade has been aligned.
Step 3: Support the Entire Slab
The slab must remain stable during cutting.
Large unsupported areas can vibrate or flex as the blade progresses, increasing the risk of cracking near the end of the cut.
Use the manufacturer's support tables or suitable additional support for large-format slabs.
Step 4: Check the Blade and Water Supply
Confirm:
- the blade is suitable for 20 mm porcelain;
- the blade is installed in the correct rotational direction;
- it is not visibly damaged or excessively worn;
- the machine is correctly aligned;
- water reaches the blade properly where wet cutting is required.
Step 5: Start the Cut Slowly
Introduce the blade into the porcelain smoothly.
Do not force the blade simply because the material is hard.
The diamond abrasive should remove the material progressively.
Step 6: Maintain a Controlled Feed Rate
A steady feed is generally more effective than repeatedly accelerating and slowing the slab or cutting head.
Excessive force can increase:
- blade deflection;
- vibration;
- heat;
- edge chipping;
- motor loading.
The exact feed rate depends on the blade, machine and slab rather than one universal speed.
Step 7: Control the Exit Edge
The final section of the cut deserves particular care because the remaining porcelain becomes progressively less supported.
Slow the feed where necessary and ensure both sides of the slab remain supported.
Some experienced installers make a short relief cut from the exit edge before completing the main cut. Whether this is appropriate depends on the machine, blade and cut geometry.
Step 8: Finish the Cut Edge
Minor micro-chipping can be refined with a suitable diamond hand pad or polishing pad.
For visible edges, progress carefully rather than aggressively grinding the surface.
The objective is to remove sharp micro-chips without changing the dimensions or creating an obvious bevel unless the design requires one.
How to Cut L-Shapes and Notches in Porcelain
L-shaped cuts are more demanding because the internal corner can concentrate stress.
Typical applications include cutting around:
- walls;
- door thresholds;
- posts;
- drainage channels;
- inspection covers.
Mark both cut lines precisely and avoid forcing the blade beyond the intended intersection.
For detailed work, an angle grinder with an appropriate porcelain blade can provide better manoeuvrability than a large bridge saw.
Avoid creating unnecessary sharp internal stress points where the design can be adjusted.
How to Cut Curves in Porcelain Paving
Curved cuts are normally completed with a suitable grinder rather than a conventional bridge saw.
Work progressively rather than attempting to force the entire curve in one aggressive pass.
The tighter the radius, the greater the difficulty of producing a smooth finished edge.
Where the cut remains visible, final dressing with appropriate diamond finishing pads can improve the appearance.
How to Make Holes in Porcelain Paving
Holes for pipes, lighting or other services generally require a suitable diamond core bit rated for porcelain.
Support the slab properly and follow the drill manufacturer's requirements for:
- cooling;
- drill speed;
- entry angle;
- maximum operating RPM.
Ordinary masonry drill bits are not a substitute for appropriate porcelain drilling equipment.
Should 20 mm Porcelain Be Cut Wet or Dry?
For repeated high-quality straight cuts, wet cutting is normally preferred.
Water provides several advantages:
- it cools the diamond blade;
- it reduces airborne dust;
- it helps remove cutting debris;
- it can extend blade life;
- it can improve cutting consistency.
However, some specialist grinder blades are specifically manufactured for dry cutting thick porcelain.
Dry cutting should therefore not be described as technically impossible, but it requires the correct blade, suitable equipment and effective dust control.
Silica Dust and Cutting Safety
Powered cutting, drilling and grinding of ceramic and mineral-based construction materials can generate harmful fine dust.
Where wet cutting is practical, effective water suppression is an important method of reducing airborne dust.
Anyone carrying out powered cutting should also follow the relevant tool, blade and workplace safety requirements and use appropriate:
- eye protection;
- hearing protection;
- protective footwear;
- hand protection;
- respiratory protective equipment where required.
Do not assume that cutting outdoors makes uncontrolled dust harmless.
Dust control matters. Dry cutting with grinders and other powered tools can generate high concentrations of fine airborne dust. Use wet suppression or suitable extraction where applicable and follow UK workplace dust-control requirements.
Why Full Slab Support Matters
A good blade cannot compensate for an unstable slab.
During cutting, the porcelain should remain:
- flat;
- properly supported;
- free from rocking;
- clear of debris beneath the cutting area.
If one side drops or vibrates as the cut nears completion, the remaining porcelain bridge can fracture suddenly.
This is particularly important with 900 × 600 mm and other large-format slabs.
Why Does a Porcelain Blade Start Cutting Slowly?
A blade that initially cut well but begins to slow can have several causes:
- diamond segments becoming glazed;
- blade wear;
- incorrect feed pressure;
- insufficient cooling;
- machine misalignment;
- using a blade unsuited to thick porcelain.
Some diamond blades require periodic dressing or sharpening using the method specified by the blade manufacturer.
Do not automatically increase pressure when cutting becomes slower. That can increase blade deflection and chipping rather than solving the underlying problem.
Common Porcelain Cutting Problems
Chipped Decorative Surface
Common causes include:
- unsuitable blade;
- worn or damaged blade;
- excessive feed pressure;
- poor slab support;
- insufficient cooling where wet cutting is specified;
- blade or machine vibration.
Slab Cracks Before the Cut Is Complete
This is commonly associated with:
- unsupported slab sections;
- excessive vibration;
- forcing the blade;
- stress around complex cuts;
- poor control at the blade exit point.
Blade Wanders Away from the Cut Line
Possible causes include:
- blade deflection;
- excessive pressure;
- worn blade;
- machine alignment problems;
- poor guidance when using a handheld grinder.
Cut Edge Is Rough
A rough edge may result from an unsuitable blade, excessive cutting speed or aggressive blade geometry.
Where the edge remains visible, it may require careful finishing with an appropriate diamond pad.
Do Visible Porcelain Edges Need Special Treatment?
Most cut edges disappear within patio joints, but exposed edges occur around:
- steps;
- raised patios;
- copings;
- wall caps;
- exposed boundaries.
These cuts require greater attention because ordinary printed porcelain can have a body colour different from the decorative surface.
Where exposed cut edges form an important part of the design, a suitable coloured-body or Full-Body Porcelain Paving product can provide a more coordinated appearance.
How Much Extra Porcelain Should Be Allowed for Cutting?
Cutting increases wastage, particularly on patios containing:
- many corners;
- steps;
- curves;
- inspection chambers;
- drainage channels;
- diagonal layouts;
- narrow perimeter pieces.
For many straightforward projects, approximately 8–10% extra material is a practical allowance.
Small or more complicated layouts can require approximately 10–15%.
Accurate setting-out before cutting can reduce avoidable waste.
Cut Porcelain Before Applying Slurry Primer
Complete measuring, cutting and dry fitting before the slab is primed.
This allows the installer to:
- check the fit;
- inspect the cut edge;
- make small adjustments;
- clean the slab;
- avoid contaminating cutting equipment with wet slurry primer.
Once the piece fits correctly, apply slurry primer to the complete underside and install it onto the fresh mortar bed.
For the complete laying sequence, see How to Lay Porcelain Paving Slabs.
Porcelain Cutting Mistakes to Avoid
- Using a general masonry blade instead of a porcelain-rated blade
- Ignoring the blade manufacturer's wet or dry cutting requirement
- Forcing the blade through the slab
- Cutting large slabs without adequate support
- Using a damaged, worn or glazed blade
- Attempting long precision cuts freehand where a guided saw is available
- Applying excessive grinder pressure around internal corners
- Ignoring dust control during powered cutting
- Failing to dry-fit the cut slab before installation
- Leaving sharp micro-chipped edges where they will remain exposed
For other installation failures, see What Should You Avoid with Porcelain Paving?.
Final Advice for Cutting 20 mm Porcelain
Clean porcelain cutting depends on matching the blade, machine and technique to the material.
For repeated straight cuts, a well-set-up wet bridge saw with a specialist 20 mm porcelain blade is usually the most controlled method.
Angle grinders remain useful for curves, notches and detailed work when fitted with a compatible blade and used by an experienced operator.
The most important principles are:
- use a blade specifically rated for thick porcelain;
- support the slab completely;
- use water where the cutting system requires it;
- control cutting dust;
- do not force the blade;
- slow down around corners and cut exits;
- finish exposed edges carefully.
Cutting 20 mm Porcelain FAQs
What is the best tool for cutting 20 mm porcelain paving?
A suitable wet bridge saw fitted with a diamond blade specifically rated for thick porcelain is normally the preferred tool for repeated straight cuts. An angle grinder with an appropriate porcelain blade is useful for curves, notches and detailed work.
Can you cut 20 mm porcelain with an angle grinder?
Yes. A suitable angle grinder can cut 20 mm porcelain when fitted with a blade specifically rated for porcelain and the intended wet or dry cutting method. It is particularly useful for short cuts, curves and notches.
Does 20 mm porcelain have to be wet-cut?
Not in every case. Wet cutting is normally preferred for repeated clean straight cuts because it cools the blade and suppresses dust, but specialist dry-cutting blades for 20 mm porcelain also exist. Always follow the blade and machine manufacturer's specification.
What diamond blade should be used for porcelain paving?
Use a high-quality diamond blade specifically rated for thick porcelain or porcelain stoneware. Depending on the manufacturer and machine, suitable blades may use continuous-rim, turbo or specialist segmented designs.
Why does porcelain chip when it is cut?
Chipping can result from an unsuitable or worn blade, excessive pressure, slab vibration, poor support, insufficient cooling where wet cutting is required or loss of control as the blade exits the slab.
How do you smooth a cut porcelain edge?
Minor micro-chipping can be dressed using an appropriate diamond hand pad or polishing pad. Visible edges should be finished carefully so the slab dimensions and intended edge profile are not altered unnecessarily.
