Internal Plastering Quantities Estimator (UK & USA)

This calculator helps you estimate the quantity of plaster needed for internal walls and ceilings. Whether you're working on a home remodel in Leeds or drywall refinishing in Los Angeles, this tool gives you an accurate starting point.

Technical Guidance

• 🇬🇧 UK: Typical coverage is 11m² per 25kg bag at 2mm thickness.
• 🇺🇸 USA: Estimate using coverage per square foot; 1 bag = approx. 125–150 ft² at 2mm.
• Recommended thickness: 2–3mm for skim coat, up to 10mm for base + finish coat.

Plaster Coverage Table

Material Density

Pro Tips

• Apply in two layers for better finish—scratch then skim.
• Always allow for 10% wastage when ordering materials.
• Use bonding agents on difficult surfaces for better adhesion.

Common Mistakes

• Overmixing reduces workability and bonding strength.
• Applying thick layers causes cracking on drying.
• Skipping surface prep leads to poor adhesion.

FAQs

• How many bags of plaster for 20m² wall?
  Roughly 2 bags for 2mm skim thickness.
• What type of plaster is best for old walls?
  Use bonding or browning plaster before finishing.
• Can I paint directly on fresh plaster?
  Wait until it's fully dry and apply mist coat first.