Installation of Mitred Tile Edges (Jolly Edges)

The job looks simple, but fractions of a millimetre decide the result. The usual process goes like this.

Checking the corner and the background

The wall corner must be straight and square. If the plaster on the corner is wavy or leans off true, the tiles will not meet along their full length and a gap will open up. So the tiler first checks the corner with a spirit level and a square and corrects it where needed. The background should be firm, dry and free of dust. In wet areas it also needs waterproofing (tanking).

Cutting and grinding

The cut is made on a wet tile saw with a tilting table and a diamond blade, or on a dedicated mitre machine. The tile is cut from the back. One detail matters a lot: the edge is not ground to a knife point. A thin strip, usually around one millimetre, is left on the face so the glaze does not chip. The angle is often set just under 45 degrees, so the tiles touch at the face and leave a little room behind for adhesive.

Smoothing the edge

After cutting, the edge is dressed with a diamond hand pad or a fine blade. This removes small chips and rounds the sharp edge slightly, so you cannot cut yourself on the corner and it copes better with knocks.

Fixing

The tiles go on with a flexible adhesive, usually back-buttered (adhesive on the wall and on the back of the tile) so there are no voids behind the corner. Both sides of the corner are fixed at the same time or straight after each other, and the tiler keeps checking that the faces sit flush. Any adhesive squeezed into the joint is removed straight away.

Grouting and cleaning

Once the adhesive has cured according to the manufacturer's instructions, the fine joint on the corner is filled with grout in the same colour as the other joints. In showers, epoxy grout is often chosen because it takes up less water and dirt. Finally the surface is cleaned and the corner is checked along its full height.

A Jolly edge looks neat, but it does not suit every corner. A metal or plastic trim protects the corner. A Jolly edge only closes it off visually. A ceramic corner is also more sensitive to a hard knock than an aluminium profile.

• A Jolly edge suits places where you want a clean look and the corner is not knocked often: window reveals, niches, shower shelves, corners of bathroom tiling.
• A trim is more practical in busy spots: hallways, corners where furniture or a pushchair goes past, stairs, public areas.

The material matters too. On a glazed tile with a white or reddish body, the ground edge will show a strip of a different colour. Through-body porcelain, where the colour runs through the whole tile, gives much better results because the cut matches the surface. Glass mosaic and very thin tiles are poorly suited to a Jolly edge.

How demanding the job is, and therefore what it costs, depends mainly on the number and type of corners, not on the tiled area. The job gets harder with:

• large-format tiles, where a long cut is harder to keep straight and the tile is awkward to handle,
• hard porcelain and thick tiles, which cut more slowly and wear the blade faster,
• an out-of-true wall corner, which has to be corrected first,
• short pieces and fiddly details such as niches, where three edges meet at one point,
• a pattern or veining that has to carry on around the corner.

A straight corner, a medium tile size and through-body material make the work much easier. In practice a few tiles usually crack during cutting, so it pays to have spare tiles from the same production batch.

• Edge ground to a sharp point. The glaze chips during cutting or later when the corner gets knocked.
• A void behind the corner. If adhesive does not fill the space behind the joint, the corner cracks on impact.
• Exactly 45 degrees on both pieces. The tiles may then touch at the back and leave a gap at the front.
• Wall corner not checked. The joint opens and closes along its height.
• Jolly edge in the wrong place. On a busy hallway corner it will chip sooner or later.

If you already have tiling experience and a wet tile saw with a tilting table, you can try a Jolly edge on something small such as a niche or a window reveal. Wear safety glasses, gloves and ear protection, and practise on offcuts first.

1. Check the corner with a spirit level and a square, and correct any unevenness.
2. Set the saw table just under 45 degrees and make a test cut on an offcut.
3. Cut from the back of the tile and leave a thin strip of about one millimetre on the face.
4. Hold two test pieces together and check that they touch at the face along the whole length.
5. Smooth the edge with a diamond hand pad.
6. Spread flexible adhesive on the wall and on the back of the tile.
7. Fix both sides of the corner, line them up and clear excess adhesive from the joint.
8. Once the adhesive has cured, grout the corner and clean the surface.

For large formats, hard porcelain or highly visible corners in living areas, it is wiser to leave the work to a tiler.

• The corner joint has the same width along its full height
• Both tiles sit flush and neither stands proud of the other
• The edge has no chips, cracks or sharp spots
• The ground edge does not show a distracting colour difference
• Tapping lightly on the corner does not give a hollow sound
• The grout is fully filled and matches the rest of the tiling
• Any pattern or veining continues around the corner
• The surface is clean, with no adhesive or grout residue