How do I calculate the "net wall area"?
Multiply the full length of the wall by its height, then subtract the area of doors and windows (a standard door is about 2.2 m², and each window per its actual size). Example: a wall 10m long and 3m high = 30m², minus a 2m² door and two 1.5m² windows each = 30 − 2 − 3 = 25m² net.
What block size does this calculation assume?
The standard cement block commonly used in Saudi Arabia (20×20×40 cm), at a rate of 12.5 blocks per square meter of wall — the most commonly used standard in contractor estimates.
Why are there two types of cement in the result (mortar and plaster)?
"Mortar" cement is used to bond the blocks together during construction, while "plaster" cement (rendering) is used later to cover the wall surface with a smooth layer in preparation for painting. These are two separate needs that are added together in the final total.
Does the quantity include a waste allowance during construction?
Yes, we automatically added 5% waste to the block count only (the common rate for breakage and cutting waste), while cement and paint are calculated at theoretical precision with no extra margin — it's still a good idea to buy a small extra amount of cement as a buffer.
How many liters of paint do I actually need?
It depends on the paint type and surface smoothness, but the common rate in approved paint specifications is coverage of 10m² per liter per coat. The calculator uses this rate multiplied by the number of coats (two coats is most common for water-based paint) and the area of the sides you chose to plaster/paint.
