Planning to plaster over existing surfaces? Accurate quantities depend on the wall's size, condition, plaster type and the manufacturer's coverage data. This calculator uses your numbers rather than pretending every house is the same.
Estimate materials required
How to measure
- Measure each wall's height and width in metres, then multiply the two figures for its area.
- Add all wall areas together and deduct the actual sizes of windows and doors.
- Inspect irregular patches, damaged or uneven plaster and areas that might need additional depth or separate repair.
- Enter the resulting net area in square metres.
Which coverage figure should you use?
Use the actual product label or the manufacturer's technical data for the proposed plaster and coat thickness. Coverage differs between bag sizes, products and application thickness. If the data provides a consumption rate in kg per square metre instead, first convert it to square metres per bag using the bag weight.
Check adhesion, the cause of damp, incompatible existing materials and structural movement. Covering loose or damp plaster may hide defects rather than solve them. Seek appropriate specialist advice where necessary.
What the estimate does not include
Primer or bonding agents, mesh, corner beads, patch repairs, substrate preparation, tools, scaffolding, labour, transport, and additional coats are not included. This is a planning aid, not a professional material specification or quote.
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