Which coving should I choose — plaster, polystyrene or duropolymer?
Four materials with very different weights, prices, finishes and fitting methods, and an honest account of which one suits a period room, a rental, a bathroom and a first attempt.
- Difficulty
- beginner
- Time
- 20 min
- Read
- 4 min
Short answer
Gypsum plaster coving is the traditional, heavy, crisp-profiled option that fills and paints beautifully and needs proper support while it sets. Duropolymer and polyurethane are lighter, tougher and hold detail well, at a higher price. Polystyrene is cheapest and easiest but dents if you look at it and is a fire consideration. Paper-faced plaster coving is the middle ground and what most British rooms have.
Coving is one of the few products where the material genuinely changes both the look and the job. The weight decides how it is fixed and whether you can do it alone; the density decides how crisply the profile reads and how it survives a vacuum cleaner; and the material decides whether it can go in a bathroom.
Step by step
- Start with the room and its period.A plain 100mm cove suits almost any modern room. A Victorian or Edwardian room usually wants a deeper, more elaborate profile, and matching the original in adjoining rooms matters more than the material does.
- Check the profile against the room's proportions.Deep coving in a low room closes it in visibly. Measure the drop on the wall and mark it in pencil before buying — the difference between a 100mm and a 170mm cove is much larger on the wall than it looks in a shop.
- Decide by where it is going.Bathroom or kitchen: a polymer that does not care about moisture. Hallway, stairs and children's rooms: something dense enough to survive knocks. Spare bedroom: anything. Escape routes: not polystyrene.
- Decide by who is fitting it.Polymer and polystyrene are light enough to hold in place one-handed while the adhesive grabs. Plaster coving in long lengths needs support or a second person, and a 4m length of plaster cornice is genuinely awkward to carry up a stairwell without breaking it.
- Check the fixing method matches the material.Each type has an adhesive intended for it, and they are not interchangeable — polystyrene adhesive will not hold plaster coving, and gypsum-based coving adhesive does not bond well to polymer. Buy the adhesive with the coving.
- Compare on installed cost, not material cost.Polystyrene is a fraction of the price per metre but looks it. Plaster coving is inexpensive and looks right. Polymer costs several times as much and is only worth it where the toughness or the moisture resistance is doing something.
- Buy one length and hold it up before committing.Profiles look completely different at ceiling height in the room's own light than they do in a rack. This one step prevents most regret.
Tips
- Matching existing coving in an adjoining room is often impossible from stock, and a specialist can take a mould from a short piece of the original if it matters.
- Coving takes the ceiling colour by convention, but painting it the wall colour lowers a high ceiling visually and painting it the ceiling colour raises a low one.
- If you are overboarding a ceiling, the coving comes off first, and plaster coving rarely survives removal intact — factor replacement into the decision.
Alternatives
- Gypsum plaster coving: The standard British coving: a plaster core with a paper facing, in profiles from a simple cove to elaborate cornices. Crisp detail, takes filler and paint identically to the wall, heavy enough to need support while the adhesive grabs, and it will break if it is dropped. The default choice for most rooms.
- Duropolymer and high-density polyurethane: Moulded from dense foam polymers. Light, extremely tough, holds fine detail, does not absorb water, and can be used in bathrooms. Considerably more expensive, and it is fitted with its own adhesive. The best choice where the coving will get knocked or is in a damp room.
- Expanded polystyrene: Very cheap, very light, fitted with tile-style adhesive, and easy to cut with a knife. It dents under any pressure, the surface texture is visible under paint, and it is a fire consideration on escape routes. Reasonable in a spare room, a poor choice in a hallway.
- Timber and MDF cornice: Machined mouldings fixed mechanically. Very robust, suits some period and contemporary schemes, and joints have to be mitred and filled like any timber trim. Heavier and slower than coving, and the joints move seasonally.
- Run-in-situ fibrous plaster: Cornice formed on site or cast in a workshop by a specialist. This is what elaborate period cornices are, it can be matched exactly for a restoration, and it is priced accordingly. The right answer for repairing or extending original plasterwork.
Questions people ask
Is polystyrene coving a fire risk?
Expanded polystyrene burns readily and produces dense smoke. As a small decorative element it is not the same order of risk as a whole ceiling of polystyrene tiles, but on a stairwell or hallway — the escape route — a non-combustible or fire-rated alternative is the sensible choice.
Can I put coving in a bathroom?
Yes, with a polymer coving and a suitable adhesive. Plaster coving in a room that gets steamy repeatedly can soften at the joints and stain, particularly right above a shower.
What size coving should I get?
As a rule of thumb, larger rooms and higher ceilings carry deeper profiles, and a standard modern room with a 2.4m ceiling suits something around 100 to 127mm. Hold a length up before deciding.