Skim over existing walls / ceilings: calculator for UK builders
Answer the measurements this calculation needs and JobBosh works out the materials with wastage and pack rounding, the labour hours by role, the plant, the waste and the site needs - then prices them from your own figures, a supplier's quotation or a dated price you record. Free, no account needed to start.
What it works out
- Material: Finish plaster (25 kg); PVA / bonding agent
- Labour: Two-coat skim
The questions it asks
| Question | Unit / choices | Required? | Help |
|---|---|---|---|
| Area to skim | m2 | required | |
| Existing surface | one of: sound plaster, painted, artex, uneven | optional - default sound_plaster (labelled assumed) |
The norms behind it, with their sources
Coverage, productivity and wastage defaults you can edit; each carries where it comes from and is shown as assumed until your own benchmark replaces it.
| Norm | Value | Source | Tier |
|---|---|---|---|
| Finish plaster per m2 | 2.6 kg/m2 | typical manufacturer figure | assumed |
| PVA / bonding agent coverage | 6 m2/L | typical manufacturer figure | assumed |
| Two-coat skim per m2 | 0.3 hr/m2 | trade practice | assumed |
| Scratch / bond painted surfaces | 0.1 hr/m2 | trade practice | assumed |
| Scrape high spots / bond artex (asbestos test first) | 0.3 hr/m2 | trade practice | assumed |
A worked example
Answers used: Area to skim 20 m2; Existing surface sound plaster. These are the recipe's own quantities for those answers - the prices are yours, the supplier's or a quotation's, never a figure typed on a web page.
| Kind | Line | Quantity | How it is worked out |
|---|---|---|---|
| material | Finish plaster (25 kg) | 54.6 kg 3 x bag - 25 kg bags | 20 m2 x 2.6 kg/m2 |
| material | PVA / bonding agent | 3.33 L 1 x tin - 5 L | 20 m2 / 6 m2 per litre |
| labour | Two-coat skim | 6 hr | 20 m2 x 0.3 h/m2 |
Labour on this example: about 6 hours across the roles; at your rates it becomes money.
Site questions this work raises: Protection and cleanliness, Utilities and welfare.
Then what
Price the lines from your crew rates and your material prices (each with its source and date), answer the site questions (parking, skip, welfare, power, water, protection), let JobBosh draft the supplier enquiries you approve, and issue a branded quotation your customer accepts on a secure link. Guest work is kept for 14 days; a free account keeps it for good.