Plaster Works Materials Quantity Measurement

Materials Quantity Measurement for Plaster Works

Below is a concise, practical guide with formulas, standard assumptions, material‑per‑volume rates, a worked example, and a ready BOQ table you can apply directly on site.

Key Steps and Formulas

• Measure area: total surface area to be plastered minus openings.
• Choose thickness: typical values — 12 mm for internal walls, 15 mm for external walls.
• Compute wet volume using:

Wet Volume=A×t

where A is area in m² and t is thickness in metres (e.g., 12 mm = 0.012 m).

• Convert to dry volume (allowing for bulking, voids, and wastage):

Dry Volume=Wet Volume×1.33

(Use factor 1.30–1.35 depending on sand moisture and site practice).

Typical Material Quantities per 1 m³ Dry Plaster Volume

Mix Ratio	Cement (bags 50 kg)	Cement (kg)	Sand (m³)
1:4	8.5	425	0.80
1:5	7.0	350	0.90
1:6	6.0	300	1.00

Values are standard practical estimates used by calculators and civil‑engineering references. Adjust for local material specific gravity and site wastage.

Worked Example

Given: A=100 m2, t=12 mm=0.012 m, mix 1:4.

• Wet volume:

Wet Volume=100×0.012=1.2 m3

• Dry volume (factor 1.33):

Dry Volume=1.2×1.33=1.596 m3≈1.60 m3

• Cement (bags):

Cement bags=1.60×8.5=13.6 bags≈14 bags

• Sand:

Sand=1.60×0.80=1.28 m3

These steps follow standard plaster calculators and field practice.

Ready BOQ Template (per 1 m² at 12 mm and for the Example 100 m²)

Item	Unit	Qty per 1 m² (12 mm)	Qty for 100 m²
Wet plaster volume	m³	0.012	1.20
Dry plaster volume (×1.33)	m³	0.016	1.60
Cement (1:4)	bags 50 kg	0.136	13.6 ≈ 14
Sand (1:4)	m³	0.008	1.28

(Quantities rounded for procurement; keep 5–10% extra for site wastage.)

Practical Notes and Assumptions

• Thickness: use project specification; ceilings often 10 mm, external 15–20 mm.
• Dry conversion factor: use 1.30–1.35 depending on sand moisture and grading.
• Mix selection: 1:4 for external or high‑strength finish; 1:5–1:6 for internal non‑critical finishes.
• Wastage: add 5–10% extra to final procurement quantities for handling losses and uneven surfaces.
• Site verification: measure actual surface area on site and confirm sand specific gravity before final ordering.