How much does it cost to plaster a room?
Enter the wall (and ceiling) area to plaster and we'll work out the bags of plaster, labour and total cost — showing exactly how many bags of Multi-Finish your area needs and why.
Tip: a wall is roughly length × height. A 4 m × 2.4 m wall ≈ 9.6 m².
| Multi-Finish plaster | 3 × 25 kg bag | £39 |
- 1Area to plaster: 30 m²
- 2Skim plaster: 30 m² ÷ 10 m² per 25 kg bag = 3 bags of Multi-Finish
- Multi-Finish covers ~10 m² per 25 kg bag at a 2 mm skim.
- Assumes a sound, flat background to skim onto.
How plastering quantities are worked out
- 1Measure the area to skim
Add the wall areas (length × height) and the ceiling (length × width) if it's being done. A typical bedroom is ~30 m² of wall plus ~12 m² of ceiling.
- 2Skim coverage
One 25 kg bag of Thistle Multi-Finish covers about 10 m² at a 2 mm skim. Bags = area ÷ 10, rounded up.
- 3Add a backing coat if needed
Bare brick or where you're building up thickness needs a bonding/undercoat first — about 3 m² per 25 kg bag at 11 mm — before the skim.
- 4Add labour
A plasterer skims roughly 35 m² a day. Labour = area ÷ 35 × the day rate.
Plastering quotes vary wildly, which makes it hard to know if you're being overcharged. Knowing the material side — a bag of Multi-Finish covers about 10 m² — lets you sanity-check a price. A 30 m² room needs only ~3 bags of plaster (under £40 of material); the rest is skilled labour. The calculator separates the two so you can see where the money goes.
Typical cost to plaster a room (indicative)
| Room | Wall + ceiling | Indicative cost |
|---|---|---|
| Small bedroom / box room | ~28 m² | £350 – £550 |
| Average double bedroom | ~42 m² | £500 – £750 |
| Living room | ~55 m² | £650 – £950 |
| Ceiling only (avg room) | ~12 m² | £180 – £300 |
Skim onto sound backgrounds. Boarding out or two-coat work costs more. Indicative — confirm with quotes.
Frequently asked questions
How much does it cost to plaster a room?+
For an average double bedroom (walls and ceiling ~42 m²), expect roughly £500–£750 to skim, including materials and labour. Smaller rooms are less; living rooms and two-coat work are more. The calculator gives a figure for your exact area.
How many bags of plaster do I need?+
One 25 kg bag of Multi-Finish covers about 10 m² at a 2 mm skim, so divide your area by 10 and round up. A 30 m² room needs 3 bags. The calculator shows this calculation and adds bonding if you choose a two-coat job.
Is it cheaper to plaster or plasterboard?+
Skimming an existing sound wall is cheapest. If the wall is in poor condition, dot-and-dab plasterboard then skim ('board and skim') can be quicker than patching and re-plastering — the calculator's 'plasterboard & skim' option estimates both.
How long does plastering take to dry?+
Fresh plaster typically takes 2–7 days to dry fully depending on thickness, ventilation and the weather. Wait until it's a uniform pale colour before misting and painting.
Related tools & guides
Cost figures shown are indicative estimates, not quotations. You are responsible for verifying all costs (obtain contractor quotes) and any figures submitted to a lender. ScopeWise is a documentation tool, not financial, tax, structural or planning advice. HMO compliance prompts are guidance only — confirm requirements with your local council, as standards and licensing vary by authority.