How do I cut internal corners for coving?

Use a mitre box or mitre saw. For internal corners, place the coving upside down in the mitre box with the ceiling edge flat on the base. Cut at 45° — the left piece gets a right-hand mitre and vice versa. Many manufacturers provide paper templates that can be held against the coving for marking. Test-fit before applying adhesive.

What adhesive should I use for coving?

Use a proprietary coving adhesive such as Gyproc Coving Adhesive for plaster/polystyrene coving. Apply generously to both the ceiling and wall edges. For heavy plaster cornice, use additional support pins (panel pins driven through the coving into the wall) until the adhesive sets. Grab adhesive is an alternative for lightweight coving.

Should I remove old coving before fitting new?

Yes, always remove old coving. Use a wide bolster chisel and mallet to carefully prise it away. Score along the edges with a Stanley knife to prevent tearing the plaster. Remove all old adhesive residue and make good any damaged plaster. New coving will not bond properly over old adhesive or uneven surfaces.

What size coving should I choose?

For standard 2.4 m ceiling height rooms, 100-127 mm coving works well. For rooms with higher ceilings (2.7 m+), use 127-150 mm or larger. Small rooms look better with smaller coving profiles. The coving should be proportional to the room — too large overwhelms a small room, too small looks mean in a large room.

How do I deal with uneven walls or ceilings?

Apply a generous bead of coving adhesive and push the coving firmly into position. The adhesive will fill small gaps up to 5 mm. For larger gaps, apply extra adhesive or use decorators caulk after fitting. If the wall or ceiling is severely uneven, skim the area first or use flexible coving which accommodates irregularities better.

How to Install Coving

Tools and Materials

Tools Required

Mitre box or mitre saw
Fine-tooth saw (for clean cuts)
Tape measure and pencil
Step ladder
Filling knife or small trowel
Sponge and bucket of water
Caulk gun
Sandpaper (120 grit)
Panel pins and hammer (for heavy cornice)

Materials Required

Coving or cornice (add 10% for cuts/waste)
Coving adhesive
Decorators caulk
Fine surface filler
Paint (emulsion to match ceiling)

Before You Start

Remove any old coving and clean the wall and ceiling surfaces
Mark the coving line on the wall and ceiling by holding a piece in position and drawing along both edges
Score along the marked lines with a Stanley knife — this helps the adhesive grip
Plan your starting point — begin at the wall opposite the door for the best visual impact
Practice mitre cuts on offcuts before cutting the actual pieces

Step-by-Step Installation

Step 1 — Mark the guide lines. Hold a piece of coving in position in the corner and draw along the bottom edge (wall) and top edge (ceiling) with a pencil. Repeat at each corner to create continuous guide lines around the room.
Step 2 — Score the surfaces. Score the wall and ceiling between the guide lines with a Stanley knife or old screwdriver to create a key for the adhesive. Remove any loose paint or wallpaper within this area.
Step 3 — Cut the first corner pieces. Cut the internal corner mitres for the first corner using a mitre box. Remember: the coving sits upside down in the mitre box. Cut a left and right mitre and test-fit them in the corner before applying adhesive.
Step 4 — Apply adhesive. Apply a continuous bead of coving adhesive to both the ceiling edge and wall edge of the coving. Apply generously — excess can be wiped away.
Step 5 — Fix the first piece. Press the coving firmly into position, aligning with the guide lines. Slide it gently into the corner. Wipe away excess adhesive with a damp sponge. For heavy cornice, drive a few panel pins through the coving to hold it while the adhesive sets.
Step 6 — Continue around the room. Work around the room, cutting mitres for each corner. For straight joins, cut both pieces at a slight angle (scarf joint) rather than butting square ends together. Apply adhesive to both the wall/ceiling edges and the joint faces.
Step 7 — External corners. For external corners (chimney breasts, box-outs), cut external mitres — the opposite direction to internal corners. Glue the mitre faces together for a strong joint.
Step 8 — Fill and finish. Once the adhesive has set (typically 4-6 hours), fill any gaps at joints and along the edges with fine filler or caulk. Sand smooth when dry. Apply paint to match the ceiling — coving is usually painted the same colour as the ceiling.

Common Mistakes

Putting the coving the right way up in the mitre box — it must sit upside down with the ceiling edge on the base
Not scoring the surfaces — adhesive does not grip well on smooth painted surfaces
Skimping on adhesive — use plenty; it is much easier to wipe away excess than fill gaps later
Not supporting heavy cornice with pins — it will slide down before the adhesive sets
Rushing the corner joints — take time to test-fit dry before applying adhesive

Cost Estimate (2026)

Item	Typical Cost
Polystyrene coving (per 2 m length)	£2-5
Plaster coving (per 2 m length)	£5-15
Decorative cornice (per 2 m length)	£15-40
Coving adhesive (per tub)	£5-10
Total (average room 12 m perimeter, plaster coving, DIY)	£50-120

Related Calculators

Use the Coving Calculator for lengths and adhesive quantities, or the Cornice & Coving Calculator for more detailed specifications.