Ceiling cornice is the detail that finishes a room — and in older Australian homes, often defines its character entirely. This guide covers the different cornice types you'll find, how to choose for your home, and what's involved in installation and repair.
What is ceiling cornice?
Cornice is the decorative trim where your ceiling meets the wall. Functionally, it covers the join between two plasterboard surfaces. Aesthetically, it shapes how the whole room reads — from clean modern minimalism to ornate Federation-era period detail.
Why every ceiling needs cornice (or a shadow line)
The ceiling-to-wall junction is the trickiest joint in a room. Two flat surfaces meeting at 90 degrees, both prone to seasonal movement, both painted, both visible. Without cornice or a deliberate shadow line, you get visible cracking within a year as the building breathes.
Cornice solves this by covering the joint and giving the eye a defined line where the two surfaces meet. The seasonal movement still happens — it just happens behind the cornice, invisibly.
Types of ceiling cornice in Australian homes
Cove cornice
The most common modern cornice. A simple concave curve, usually 55mm or 75mm wide. Clean, neutral, suits almost any modern home. The default choice for new builds and most renovations because it's cost-effective, easy to install, and reads as intentional without drawing attention.
Square set / shadow line
Not technically cornice — instead, a deliberate recessed gap (typically 10–15mm) at the ceiling-to-wall junction with no cornice at all. Reads as contemporary and architectural. More expensive to install correctly because the framing behind needs to be exact. Increasingly popular in modern Australian builds.
Stepped cornice
A cornice with one or more rectangular steps in its profile. A common Art Deco and Inter-war style. Gives more visual weight than cove without going full ornate.
Ornate / decorative cornice
Federation, Edwardian, and Victorian Australian homes often have deep, sculpted cornice with floral, scroll, or geometric detail. Original profiles were typically run in plaster on-site by skilled tradesmen — modern versions are usually pre-formed sections in plaster, polyurethane, or polystyrene.
Picture rail cornice
A cornice that incorporates a horizontal rail intended to hang picture frames from. Common in Federation and Inter-war Australian homes. Aesthetically distinct even if you don't use it for hanging.
Cornice materials
- Plaster (gypsum) — the traditional and still most-used material in Australia. Cornice is sold in 3.6m or 4.8m lengths and cut to fit. Strong, paintable, and matches plasterboard ceilings cleanly.
- Polyurethane — lighter than plaster, doesn't crack, slightly more expensive. Often used in wet areas or large continuous runs where weight matters.
- Polystyrene — cheapest option but flammable and lower quality. Generally avoided in residential work for these reasons.
- Timber — uncommon in modern Australian homes outside of specific period restorations.
Cornice for ceiling height — choosing the right size
The cornice size should be proportional to the ceiling height:
- 2.4m ceilings (standard): 55mm or 75mm cove. Larger cornice on a low ceiling reads as oppressive.
- 2.55m–2.7m ceilings: 90mm or 100mm cove. Steps and feature profiles work well.
- 2.7m+ ceilings: 100mm+ cove, stepped profiles, or genuine ornate cornice. The room can take the visual weight.
Installing cornices for ceilings — how it's actually done
Cornice installation looks simple. Doing it well takes practice. The sequence:
- Measure and cut — accurate mitre cuts at every internal and external corner. A single sloppy mitre shows for the life of the room.
- Cornice cement — adhesive plaster compound applied to the cornice's bonding edges.
- Position and press — cornice held against the join, levelled, and pressed home until the cement squeezes through the joints.
- Tape and set — joins flushed with setting compound, taped where needed.
- Sand to paint-ready — three coats of set, full sand, ready for the painter.
Cornice repair — when it cracks or breaks
Cornice cracks at the wall or ceiling junction are extremely common. The cause is almost always the seasonal expansion and contraction of the building. Surface cracks can be re-tape-and-set; deeper cracking or detached sections need section replacement.
The challenge in older homes is matching the existing profile. Modern stock cornice covers most standard profiles. Period ornate cornice often needs to be sourced or, in rare cases, custom-run from a mould of the original.
Cornice cost in Australia
For a standard room, cornice installation as part of a ceiling replacement typically adds a few hundred dollars to the job. Standalone cornice replacement (existing ceiling kept, just cornice replaced) costs more per linear metre because the access and setup is fixed regardless of run length.
Period cornice matching costs more — both because the profiles are more complex to fit and because sourcing matching stock can require time.
Frequently asked
Possible for a single straight run with no mitres. Mitre cuts are the difficult part — bad mitres show for the life of the room. Most homeowners hire it out for any room with corners.
A specialist takes a profile rubbing or photograph of the existing cornice and matches it from stock. For rare period profiles, custom runs are possible but expensive.
Usually no. Hairline cracking at the cornice junction is almost always seasonal movement. Wide cracks combined with sagging ceiling or other symptoms can indicate something more.
Cornice is forgiving — small framing imperfections hide behind it. Shadow line needs everything dead-square or it shows. Cornice for older homes and budget jobs; shadow line for new builds and contemporary renovations done to a higher tolerance.
Yes — and traditionally cornice was often painted to match the wall, not the ceiling, in Federation and Victorian homes. Modern fashion is to paint cornice the ceiling colour for a cleaner read.
Need this work done in Perth?
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