About This Calculator
This calculator estimates the amount of joint compound (mud) and tape needed to finish drywall joints and screw heads. Standard practice requires three coats: a bedding coat, a fill coat, and a finishing coat.
Finishing Process
- Apply bedding compound and embed paper tape into joints
- Apply second coat, widening the feathered edge
- Apply final skim coat and sand smooth once dry
- Fill all screw/nail heads with compound (3 coats)
Tips
- • Use paper tape for most joints; mesh tape for repairs
- • Allow each coat to dry fully before the next (typically 24 hours)
- • Feather edges wider on each successive coat for a smooth finish
- • Add 10% wastage for mixing losses and corrections
Ready to Calculate?
Enter the number of drywall sheets and screw pops to get compound and tape quantities.
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UKUK Building Regulations
References & Sources
Standards Cited
- BS EN 13963 — Jointing materials for gypsum plasterboards — Definitions, requirements and test methods
Defines requirements for plasterboard jointing compounds and tapes - BS 8212 — Code of practice for dry lining and partitioning using gypsum plasterboard
Guidance on joint taping and finishing techniques for plasterboard installations
Formulas Used
- Joint length per sheet:
jointLength = sheetWidth + sheetHeight (accounting for shared edges)
Source: BS 8212 — Approximation: ~3.5m per standard UK sheet (1200x2400mm) - Compound volume:
compound = (jointLength × jointWidth) / coveragePerLitre × numberOfCoats
Source: Manufacturer coverage data — Joint feathering width ~125mm (5 inches) - Screw pop compound:
screwCompound = numberOfPops × 0.005 litres × numberOfCoats
Source: Industry practice
Key Assumptions
- Jointing compound coverage ~1.6 m2 per litre per coat (Gyproc) — Manufacturer data (Gyproc, Knauf)
- Standard tape roll: 75 m — Gyproc / Knauf standard
- Standard plasterboard sheet: 1200 x 2400 mm — BS EN 520