Construction material calculator
Quantities for blockwork, plaster, reinforcing steel, floor tiles, paint and roofing sheets from your own dimensions. Every assumption is shown and can be changed. For concrete, use the concrete calculator.
Result
- Plaster (wet), with waste
- 0.825 m³
- Cement
- 308.9 kg
- Cement bags to buy
- 7 bags of 50 kg
- Sand
- 0.858 m³
Plaster on uneven blockwork is thicker than its nominal thickness in places; measure a few spots before ordering.
No cost is estimated: the site has no verified material price observations yet, and it does not estimate a cost from an unverified figure.
What this is for
The cement and sand to plaster a wall or a ceiling to a given thickness. It is an estimate for ordering and checking, not a design or a bill of quantities for a contract.
How it works
- Wet volume = area × thickness × (1 + waste %).
- Dry volume = wet volume × the dry volume factor.
- Cement = dry volume ÷ (1 + sand parts) × bulk density; sand = the rest of the dry volume.
Assumptions
Each one is an input above. None of them is a legal or standard requirement.
| Assumption | Value used | Where it comes from |
|---|---|---|
| Plaster thickness | 0.015 m | Your choice. About 12 to 15 mm inside and 15 to 20 mm outside are usual targets. |
| Mix, sand parts to one of cement | 4 | Your choice. 1 : 4 and 1 : 6 are common plaster mixes; follow the specification. |
| Waste allowance | 10 % | Site rule of thumb. Droppings and uneven walls. Rough blockwork takes more plaster than the nominal thickness. |
| Dry volume factor for mortar | 1.3 | Site rule of thumb. Dry cement and sand take more room than the wet mortar they make; factors between about 1.27 and 1.33 are used on site. |
| Cement bulk density | 1440 kg/m³ | Material property. The loose bulk density of ordinary Portland cement, commonly taken as 1,440 kg per cubic metre for estimating. |
| Cement bag | 50 kg | Product size. Change this if your supplier sells a different bag. |
Worked example
50 m² at 15 mm with 10% waste is 0.825 m³ of plaster. At 1 : 4 and a factor of 1.3 that is 1.073 m³ dry: 308.9 kg of cement (7 bags of 50 kg) and 0.858 m³ of sand.
Limitations
- Plaster on uneven blockwork is thicker than its nominal thickness in places.
- Additives, bonding coats and finishing coats are not included.
- Quantities only: no labour, transport or cost.
Related guides
- EU and government reopen renovated school in Mogadishu
- Goobjoog: South-West State Palace Inaugurated in Baidoa, 2015
- Somaliland inaugurates Phase II of Kuwaiti-funded complex
- Telesom backs Hargeisa Group Hospital emergency ward
More in Engineering and Methods.
More tools and data are listed on the Data Hub.