How to Calculate Total Number of Blocks for Your Building;- What is the number of blocks required to complete this building/structure?
The most common question asked by many people who wishes to have their own home especially after the building design stage. Many Clients wishes to know exactly how much they are going to spend for building materials required for their proposed structure/building.
Calculate Total Number of Blocks for Your Building
For example, total number 8of blocks, total bags of cement required, and trips of sand required for the proposed building. Today we are going to show how to obtain the total number of block for your building. Firstly before we proceed it’s important for everyone to know the types of blocks, which are mostly used especially here in Tanzania. The blocks, which are mostly used, include 230mm x150mm x 450mm long and 150mm x 230mm x 450mm long concrete blocks.
So the blocks used mostly includes
- 450mm x 150mm x 230mm thick
- 450mm x 230mm x150mm thick
There are various steps to follow so that to confirm number of blocks required for your project. A simple one-bedroom house is used for this case
Step #1: Total Wall Area
To calculate total length of walls i.e. Internal walls + External Walls
Sometimes you may be given different thickness for internal and external walls. For many construction, mostly external walls appeared to have 230mm thick whereas 150mm thick for internal wall. In our case we have same thickness for internal and external wall (230mm thick wall).
Wall 1 = 15.00m (2Nr)
Wall 2 = 8.00m (3Nr)
Sum up all walls
15.00 x 2 = 30.00
8.00 x 3 = 24.00
Total wall length is 54m or 54000mm
Let assume height of the wall is 3000mm (3m)
Total wall area including openings = 54 x 3 = 162 square meters
Step #2 Deductions of all openings (door & window)
Total Number of Doors = 2nr (0.900 x 2.400)
Total Number of Windows = 5nr (1.500 x 1.500)
Total square meters (Door) = 4.32sm
Total square meters (window)= 11.25sm
Total square meters (openings) = 15.57sm
Also remember to deduct ring beam
Let 0.300m be height of ring beam
So 54 x 0.3 = 16.2sm
Total Deductions = (doors &windows) + Ring beam
= 15.57sm + 16.2sm = 31.77sm(to be deducted)
Then total wall areas = 162sm – 31.77sm =130.23sm
Area of Foundation Walls:
Also remember we have a foundation. The foundation area depends on the number of courses laid. For this building, we use four courses of block wall foundation, which is equal to 920mm high.
We simply multiply the perimeter of wall in superstructure with the foundation wall height. Area is still length x Height. But now height is 920mm.
Area of foundation Wall
54.00m x 0.92m = 49.68sm
Total wall area = Substructure walling + Superstructure walling
= 130.23 + 49.68 = 179.91sm
Step #3 Total number of blocks per 1 square meter ( For our case of 230mm thick wall)
1/0.460 x 0.16 = 13.59 blocks
Consider waste: Allow 2.5% of waste = 0.34
Total = 13.93 (14 blocks approximately)
Blocks/square meters = 14
Number of blocks = 179.91 x 14 =2518.74
Add; contingency sum 5% = 125.94
Total = 2644.67
= 2,650 blocks approximately
Therefore number of blocks is: 2,650 blocks
