Architraves and cornices both frame a room, but they sit at opposite ends of the visual story. One hugs the door; the other crowns the ceiling.
Knowing which element you are looking at saves money, time, and design mistakes. This guide shows how to tell them apart, when to use each, and how to combine them without visual clutter.
Core Identity: Where Each Element Lives
An architrave wraps the perimeter of a door or window opening. It is a border, not a lid.
Cornice rides the junction between wall and ceiling. It projects outward, casting a shadow that softens the hard corner.
Because they occupy different planes, they rarely compete for attention; instead, they bookend the room’s vertical space.
Visual Cue Checklist
Stand at the doorway. If the trim touches the casing and runs down to the floor, it is architrave.
Look up. If the moulding hovers above your head and turns the corner like a miniature roof, it is cornice.
Historic Roots and Style DNA
Architrave comes from the Greek “main beam,” the lintel resting on columns. Its ancestry is structural; today it remains a symbolic frame.
Cornice began as the top slab of a classical entablature, designed to throw rain away from the façade. Interior cornice borrowed that protective overhang and shrunk it into a decorative lip.
Knowing the origin helps you pick profiles that feel authentic rather than randomly ornate.
Period Snapshot
Georgian homes used flat, square-edged architraves and modest cornice dentils. Victorian houses went wild with layered cornices and deep architrave bolection moulds.
If you live in a 1930s semi, a bold Victorian cornice will look like costume jewelry; choose a stepped Art Deco profile instead.
Function Beyond Decoration
Architrave hides the shrinkage gap between timber frame and plaster. It also stops door edges from chipping when furniture bumps them.
Cornice masks the hairline cracks that appear where ceiling meets wall. The shadow line it creates tricks the eye into seeing a higher ceiling.
Both pieces save repainting time by shielding vulnerable edges from knocks and dust.
Hidden Services
Cornice can hide a run of LED uplighting or speaker cables. Architrave can conceal a door-reed switch for security systems.
Plan the cavity before the joiner arrives; retrofitting wires into hardwood is expensive.
Size and Proportion Rules
Wide architrave in a tiny room swallows the door. Thin architrave in a grand hall looks apologetic.
Measure the door height first. For standard 2 m doors, 70 mm architrave suits most interiors; push to 95 mm only if the skirting is equally deep.
Cornice width should echo the ceiling height: 100 mm for 2.4 m, 150 mm for 3 m, but stop at 200 mm unless you own a ballroom.
Quick Ratio
Add the room length and width in metres, then divide by ten. The result gives a sensible cornice width in millimetres for everyday homes.
Adjust up one step if the décor is lavish, down one step for minimalist schemes.
Material Landscape
Softwood architrave is cheap, paint-ready, and easy to sand when the door swells. Hardwood resists dents but costs more and needs priming on all faces to stop moisture twist.
MDF architrave has no grain, so knots cannot bleed through gloss paint. Choose moisture-resistant grade for bathrooms or the edges will puff like cereal.
Polyurethane cornice is light, pre-primed, and DIY-friendly. Plaster cornice is authentic and seamless once painted, but one dropped nail can snap a run.
Hybrid Strategy
Use MDF architrave for cost and stability, then fit a plaster cornice for authenticity. The eye reads the ceiling first, so spend the premium there.
Installation Order and Workflow
Fit architrave after the door is hung but before the skirting. The mitres sit flush on the legs, and any floor unevenness is hidden by the skirting later.
Cornice goes up after plastering and before flooring. Scaffolding boards scratch new floorboards, and plaster dust is easier to sweep off bare subfloor.
Paint cornice before final coats on walls; cutting in along a textured edge is faster than taping a freshly painted wall.
Sequence Snapshot
Door hanging → architrave → skirting → ceiling plaster → cornice → floor sanding → final paint.
DIY Mitre Mastery
Architrave legs are cut with 45° mitres at the head, but the butt joint at the sill hides uneven floors. Mark the reveal plus 5 mm, then scribe the leg length off the floor itself.
Cornice mitres are compound: the ceiling spring angle changes the cut. Make a template from off-cuts and test in the corner before wasting the full length.
Glue and pin both joints; expanding adhesive fills small gaps in polyurethane, while plaster cornice needs two-coat joint filler and a wet brush feather.
Tool Tip
A 254 mm sliding mitre saw handles architrave up to 95 mm deep. For cornice, use a fine-tooth blade and support both ends to stop the lightweight foam from snatching.
Paint and Finish Choices
Gloss on architrave bounces light and hides fingerprints near the handle. Satin on cornice softens the ceiling glow and hides hairline cracks.
Keep the architrave one shade lighter than the wall to enlarge the doorway visually. Keep cornice the same colour as the ceiling to lift the lid upwards.
Contrasting both elements in dark charcoal works only if the room has generous natural light; otherwise the borders shrink the space.
Colour Bridge
Pick a white with matching undertone for both elements. A warm white on cornice and cool white on architrave will clash even if the difference looks tiny on the swatch.
Repair and Retrofit Tactics
Split architrave can be glued and clamped if the crack is along the grain. If the corner mitre opens, inject resin, clamp, then repaint the whole leg to avoid flashing.
Missing plaster cornice sections require a latex mould taken from an intact run. Cast a replacement in situ with casting plaster, then blend with joint compound.
Polyurethane cornice snaps can be fixed with construction adhesive and a single screw sunk into a timber noggin; fill the depression with lightweight spackle.
Quick Patch
For small dents in painted architrave, melt a wax repair stick and level with a plastic card. Cornice chips can be filled with flexible caulk if the area is above eye level.
Cost Reality Check
MDF architrave runs cheap per metre, but the cost jumps when you upgrade to engineered oak. Factor in the priming time you save with pre-finished oak if your labour is billable.
Plaster cornice looks upscale yet costs less than ornate polyurethane once you add the price of a specialist fitter. DIY polyurethane avoids that labour line item entirely.
Measure every doorway and ceiling perimeter twice, then add 10 % waste for mitres. Returning to site for one missing length costs more than the material itself.
Budget Hack
Use plain MDF architrave and a simple stepped cornice. Paint both in the same high-quality gloss; the unified finish reads custom even though the profiles are stock.
Combining Both Elements Harmoniously
Let the cornice set the style tempo. If it is ornate, keep architrave quiet; if cornice is a sharp square edge, echo that flat face in a squared architrave.
Repeat the width ratio: a 70 mm architrave pairs with 100 mm cornice, while 95 mm architrave can carry 150 mm cornice without the ceiling feeling heavy.
Never match decorative motifs exactly; the eye prefers siblings, not twins. A dentil cornice and a plain stepped architrave feel related yet avoid theme-park excess.
Transition Trick
Where an architrave almost meets a cornice in a tight hallway, stop the cornice 20 mm short on both sides. The gap frames the doorway like a quiet reveal.
Common Pitfalls and Fast Fixes
Installing architrave before laying hardwood floors leads to height gaps after sanding. Slip a temporary spacer under the legs, then remove and cover the gap with a matching shoe mould.
Nailing cornice into plasterboard alone causes sagging overnight. Always find the joists or add noggins during the rough-in stage.
Painting cornice with wall paint instead of ceiling paint highlights texture differences under natural light. Buy the correct tin the first time; touch-ups on porous plaster leave flashing.
Rescue Move
If you mis-cut an architrave mitre, flip the damaged piece upside down and re-use it on the opposite side of the door. The tiny width difference is invisible at floor level.