Fit tile trim on external corners

Fit plastic or metal trim onto an external tiled corner for a neat, safe finish that suits your wall type.

AB-01Clear the area and check the cornerLay a dust sheet and clear the worktop or floor below the corner you're trimming. If you're refitting old trim, prise it off and scrape away old adhesive or silicone. Check the corner is plumb with a spirit level and run your hand over it for high spots or bumps that need sanding or filling flat first.

1 each · Dust sheet

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1 each · Torpedo spirit level

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1 small tub · Multi-purpose filler

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AB-02Work out your wall type before you startSolid brick or block feels hard and cold and gives a dull knock all over — trim and tiles go straight on with standard adhesive. Plasterboard on timber or metal studs sounds hollow between fixing points and has a slight spring to it; this is fine to tile, but use a flexible tile adhesive so grout doesn't crack as the board flexes. For dot-and-dab, tap the wall in a grid — large hollow, drummy patches mean the dabs have failed behind the board, and that needs re-fixing before you tile, not just a stronger adhesive. Lath and plaster feels soft and may flex or crumble under gentle pressure; don't tile straight onto it — board over with plasterboard or tile backer first.

AB-03Choose the right trim and adhesiveBuy PVC or metal external corner trim in the size that matches your tile thickness (commonly 6mm, 8mm, 10mm or 12.5mm) — check the pack, as the wrong size leaves tiles sitting proud or recessed. Pick a flexible tile adhesive for stud walls or dot-and-dab, and a standard adhesive for solid brick or block. For wet areas like showers, choose a waterproof or flexible adhesive and grout regardless of wall type.

1 each · PVC external tile trim (2.5m length)

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1 tub · Flexible tile adhesive (5kg tub)

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AB-04Measure and cut the trim to lengthMeasure the height you need to cover and mark the trim. Cut it with a mitre box and fine-toothed saw, or tin snips for thin PVC trim, cutting slightly long so you can trim to a snug fit. File or sand the cut edge smooth, then dry-fit the trim in the corner before mixing any adhesive.

1 each · Mitre box and hacksaw

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AB-05Bed the trim into the cornerSpread a thin bed of adhesive up the corner with a notched trowel, covering the width the trim's back flange will sit on. Press the trim in firmly, check it's plumb with your spirit level, and tape it in place with masking tape so it doesn't slip while you tile.

1 each · Notched adhesive trowel

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1 roll · Masking tape

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AB-06Tile up to the trimButter adhesive onto the back of each tile and slot its cut edge under the trim's lip, working up the wall row by row. Use tile spacers to keep joints even and check each tile sits flush with the trim's face. Wipe any adhesive off the trim as you go — it sets hard and is much harder to remove once cured.

1 pack · Tile spacers

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AB-07Leave the adhesive to cureLeave the adhesive to cure fully before grouting — check the tub for the time, usually around 24 hours. Don't remove the masking tape or knock the trim during this time.

AB-08Grout up to the trimRemove the masking tape, then apply grout to the tile joints right up to the trim's edge without grouting over the trim itself. Wipe off excess with a damp sponge before it dries, then polish the tiles once the grout has hazed over.

1 tub · Tile grout (2kg)

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1 each · Grout sponge

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AB-09Finish and tidy upWhere the trim meets a bath, shower tray or worktop, run a bead of flexible sanitary silicone rather than grout, as this joint needs to move without cracking. Give the trim and tiles a final wipe, check everything is aligned and flush, then clean your tools and dispose of packaging.

1 tube · Sanitary silicone sealant

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