Waterjet cutting of 120×120 tiles with a Jolly edge

An ordinary external corner is finished in one of two ways. Either a metal or plastic trim covers the edge, or one tile overlaps the edge of the other. Trims are practical, but you can see them. With the overlap, the side of the tile shows, including its body. A Jolly edge avoids both. Each slab is bevelled, the two are pushed together and the corner shows only a thin, almost invisible joint. With marble or stone-effect slabs, the pattern can even continue around the corner, which is a large part of why big formats are so popular.

Why waterjet? A straight bevel can also be made on a bridge saw with a tilting blade. A waterjet with abrasive, usually fine garnet sand, has several advantages. It puts no pressure or vibration on the slab the way a blade does, so it is gentler on thin, brittle material. It can do shaped cuts, curves and cut-outs in one setup, for example for a hob, a socket or a basin, along with the bevel. And the cut is computer-controlled from a drawing, so dimensions stay accurate even on long edges, where a manual cut would gradually drift.

The downside is that the machine is stationary. The slabs have to travel safely to the workshop and back, and everything depends on accurate measuring. A waterjet also leaves a slightly rough surface on the cut, and an angled cut can be a little uneven, so the edge is normally ground and finished afterwards.

Measuring and the drawing

Everything starts with precise measuring of the corner. The tiler or technician records lengths, heights and, most importantly, the real angles. In practice, wall corners and island carcasses are often not exactly 90 degrees, and then the Jolly bevel must be adjusted, otherwise the joint opens up. The measurements become a drawing that shows, for each slab, which edge is bevelled, where the cut-outs go and how the pattern should run. With strongly veined slabs, they are often laid out and numbered in advance so that the right pieces meet at the corner.

Collecting and transporting the slabs

A 120×120 cm slab is transported upright in an A-frame or on a framed pallet, never lying flat without support. For loading, a vacuum lifting frame is used, or at least a pair of suction lifters and two people. Before the workshop accepts them, each slab is checked for cracks, chipped corners and glaze defects. It helps if you are present for this check, or at least ask for photos.

The cut itself

The slab is placed on the cutting table grid so that it is supported over its whole surface and cannot sag. Straight and shaped cuts are usually done first, then the bevel. A Jolly edge is not taken to a knife edge at the face. A narrow flat, roughly 1 to 2 mm, is left on the face side. It protects the glaze from chipping and leaves room for the fine joint when the corner is fixed. An angled cut is slower than a square one because the jet passes through more material.

Finishing the edge

After cutting, the slab is rinsed of abrasive and the edge is worked with diamond polishing pads. This removes the roughness and small irregularities left by the jet, and the face flat is lightly eased so it is not sharp. On polished slabs the edge can be polished up; on matt slabs it is ground to match the matt surface. The slabs are then renumbered according to the drawing and packed with edge protection.

Return to site

The cut slabs go back to site. A bevelled edge is far more fragile than the original factory edge, so the slabs are carried in a way that keeps that edge off the floor and away from door frames. Fixing and joining the corner is done by the tiler who lays the slabs.

The costliest mistake in this job is cutting a slab to the wrong dimensions. At 120×120, a wrong slab cannot simply be replaced with an offcut. So the rule is simple: cut only once the substrate is finished.

• The substrate must be in its final state: plastered, levelled, with corner beads fitted, waterproofing done in the shower and chases for electrics finished.
• Corners to be tiled must be straight and plumb. If a corner is out, correcting it before measuring is easier than making up the difference with adhesive.
• The adhesive bed thickness must be known. Large slabs are fixed with adhesive on both the wall and the back of the tile, and the bed thickness moves the whole slab outwards, which shifts the position of the corner.
• Islands and furniture carcasses must be firmly fixed and complete. A kitchen carcass that can still move will crack a Jolly corner within weeks.
• The exact positions of cut-outs must be known: sockets, switches, taps, wastes, drains and appliances according to their installation sheets.
• Decide in advance where you want the pattern to run around the corner and where it does not matter to you.

If you live in a block of flats, think about carrying the slabs in. A 120×120 slab often does not fit into a standard lift and has to go up the stairs. It is sensible to let the building management or owners' association know in advance if common areas will be used or blocked for a while.

The price list also has a separate item for waterjet cutting of 60×60 tiles with a Jolly edge. The cutting principle is the same, but the size of the slab changes almost everything around it.

• Weight and handling: a 120×120 slab has four times the area of a 60×60 tile. At around 9 to 10 mm thick it weighs roughly 30 kg, and it is long and flexible. It needs two people with suction lifters or a frame. A 60×60 tile can be carried by one person.
• Risk of breakage: a large slab breaks if it is lifted wrongly, transported flat or cut without full support on the table. With 60×60 this risk is much lower.
• Edge length per piece: one 120×120 slab gives 1.2 m of edge, so fewer pieces and fewer setups on the table are needed for the same number of linear metres. Each cut is longer, though, and any angle error shows more.
• Angle accuracy: a bevel error that is barely visible over 60 cm becomes a joint that widens towards one end over 120 cm.
• Typical use: 120×120 is chosen when you want as few joints at the corner as possible, for example on island ends, tall niches and columns. 60×60 is more practical for small reveals, sills and floors with low skirtings.
• Replacing a damaged piece: a broken 60×60 tile is easily replaced from spares. With 120×120 the reserve is usually smaller, and buying more from a different production batch can mean a different shade.
• Transport: large slabs need an A-frame, a rack and a bigger vehicle, while small tiles travel in their boxes.

If you are unsure which format to bevel, the answer is usually decided by what you are laying. The corner should always be cut from the tile used on the surface. If the wall is in 120×120, the corner should be too, otherwise the look of the whole wall suffers.

How demanding the job is, and therefore what the whole order costs, depends on several things you can influence at the planning stage.

Makes it easier

• Straight edges without cut-outs, where the slab is simply bevelled along its full length
• An accurate drawing with numbered slabs that needs no additions
• Thicker, stiffer slabs that flex less when handled
• Through-body coloured slabs, where the colour of the tile body is not an issue
• Several identical cuts in one batch, so the machine setup is shared

Makes it harder

• Thin slabs of around 6 mm, which are very flexible at 120×120 and leave little material for the bevel
• Angles other than 90 degrees, and bevels combined with curves or cut-outs on the same slab
• Patterns that must match exactly around the corner, since specific slabs have to be selected
• High-gloss surfaces, where chipped glaze and uneven edge sheen show straight away
• Difficult site access: narrow stairs, no lift, parking far away
• Changes to dimensions after the drawing has gone to the workshop

One thing to watch in particular: on glazed tiles whose body is a different colour from the surface, a thin line of body colour appears at the Jolly corner. On a pale marble effect with a reddish body, you will see it. If you plan many Jolly corners, ask the supplier about through-body coloured slabs, or have a sample piece bevelled before you order the full quantity.

Waterjet cutting sits between measuring and tiling. It is closely linked to several trades, and most problems arise where their work meets.

• The plasterer or drylining installer prepares the corners and surfaces. Their accuracy directly decides whether the Jolly corner closes tightly.
• The electrician and plumber must have boxes and outlets in their final positions. Moving a socket after the slab has been cut means a new slab. Electrical work must be done only by a qualified electrician.
• The kitchen supplier provides the island carcass. Ask for exact dimensions and whether the carcass will have a rigid backing board under the tiles.
• The tiler fixes the slabs. Corners are usually fixed with a flexible, higher-class adhesive to EN 12004, and the joint itself is filled with a flexible grout or a colour-matched epoxy, depending on the situation. Decide how the corner will be joined before cutting, because it affects the width of the face flat.
• The stone workshop with the waterjet needs a drawing, not a verbal description. Agree clearly who makes the drawing and who is responsible for the dimensions.

It tends to work well when the same tiler who will fix the slabs does the measuring. They know their own adhesive bed and how they join corners, and there is no argument later about whether the workshop or the measurement was wrong.

As for time, the cut itself takes from several minutes to a few tens of minutes per slab, depending on edge length, thickness and the number of cut-outs. The overall time depends mostly on everything around it. Measuring and drawing usually take one site visit plus preparation. Workshops often have a queue, so several working days between handing over the drawing and getting the slabs back is normal, and longer for bigger orders. Build this gap into the schedule so the tiler is not waiting on site with no material.

After fixing, the adhesive must cure according to the manufacturer's data sheet, with standard flexible adhesives usually roughly 24 hours before grouting. Epoxy corner joints cure according to the manufacturer, and nothing should lean against the corner in the meantime. Do not load an island or niche until everything has hardened.

• A sharp edge with no flat. A bevel taken right to the face looks perfect in the workshop, but the glaze chips during fixing or at the first knock. Small chips remain on the corner that cannot be repaired without replacing the slab.
• Measuring before the substrate is finished. Once the wall is levelled, the corner moves by a few millimetres and the slabs no longer fit. The result is an open joint or one slab standing proud of the other.
• An overlooked angle. A 92 degree corner with edges bevelled at exactly 45 degrees gives a joint that is narrow at the bottom and wide at the top, or the other way round. On a 120 cm slab it is clearly visible.
• Poor handling. A slab carried flat by one edge often cracks later: a hairline crack appears after fixing. With large formats this is a frequent reason for complaints.
• A rigid joint on a moving substrate. If a corner on plasterboard or furniture is joined with a rigid material, a hairline crack appears in the joint over time or the edge comes loose.
• An unfinished edge. A rough edge left by the jet absorbs dirt and grout, and the corner looks greyish.
• Jolly on a walked-on edge. A bevelled corner on a stair nosing or step edge gets knocked and chipped over time. Ready-made step pieces or rounded edges suit stairs better.
• Mixed batches. A slab bought to replace a broken one differs in shade, and the difference is most visible exactly at the corner where two slabs meet.

Waterjet cutting is a workshop job, and handling 120×120 slabs needs two experienced people with proper lifting gear. What you can do yourself is make sure the corners and the information are ready, which prevents the most expensive mistakes.

1. Wait until plastering, levelling and waterproofing around the corner are completely finished.
2. Hold a long spirit level on both faces of each external corner and check that they are plumb along the full height.
3. Check the angle with a 3-4-5 triangle: mark 300 mm along one face and 400 mm along the other, then measure between the marks. At 500 mm the corner is square; note any difference.
4. Mark corners that are out of plumb or square and ask the plasterer to correct them before the tiler measures.
5. Confirm with the electrician and plumber that all boxes, outlets and wastes are in their final positions, and photograph them with a tape measure in shot.
6. Collect the installation sheets for the hob, sink, taps and other appliances that need cut-outs.
7. With a helper and suction lifters, stand the slabs upright side by side, choose the pieces whose pattern should meet at the corner and label them on the back with masking tape.
8. Store all slabs upright on a soft base, leaning against a wall, never lying flat.
9. Ask for one sample piece to be bevelled, check the body colour and edge finish, and only then confirm the full order.

Check twice: when you receive the cut slabs and again after they are fixed.

When the slabs arrive

Look along the edge against the light. It should be straight over its full length, with no chips on the face and an even face flat. Run a finger along it: it should not be sharp or rough. Compare the numbering with the drawing and measure the cut-out positions. Also look at the slab surface near the cut for scratches from the grid or traces of abrasive.

After fixing

The corner should show a thin, even joint along its full height or length. Place a long spirit level across both faces: the slabs should be in one plane and the corner should neither step back nor stand out. Tap lightly on the slabs near the corner; a hollow sound reveals areas without adhesive, where the edge can break off. With patterned slabs, check that the pattern continues as agreed.

Handover checklist

• All slabs are numbered and match the drawing
• The bevelled edge is straight along its full length with no glaze chips
• A narrow flat remains on the face side and the edge is not sharp
• The edge is finished and matches the surface in gloss or matt
• Cut-outs match the measured positions of boxes, taps and appliances
• Slabs show no cracks, chipped corners or machine scratches
• The fixed corner has an even joint along its full length
• Both faces at the corner are in one plane
• No hollow sound when tapping near the corner
• The pattern runs around the corner as agreed
• The corner joint is filled with the agreed, colour-matched material
• Leftovers and spare slabs are from the same batch and labelled