Good Day All..... I wish I could open a lot more thread on the Property Section but I also gat to pay the bill....
Often
times I get people asking me this question "HOW MANY BLOCKS WOULD I
NEED TO COMPLETE THIS BUILDING" immediately after handing their design
to them; I do not think it's bad to plan and budget but I always
encourage they start and not let the fear of the unknown kill the dream.
Today,
I would be breaking it down so you can actually calculate this
quantities yourself...... but, we need a plan to work with
(I have attached a simple plan & elevation for this purpose).
FOR THE PURPOSE OF THIS CALCULATION WE WOULD BE USING THE STANDARD FORM OF ARCHITECTURAL MEASUREMENT; THE MILLIMETER (mm)
DESIGN:- A GATE HOUSE.Lets
use the attached simple gatehouse design with one 900mm x 2100mm door, a
1200mm x1200mm window and a 600mm x 600mm toilet window plus a 750mm x
2100mm toilet door.
(I have done the elevation to ensure all possible elements are visible on the elevation).
OK - This is it.
Our
1st task would be to find the linear length of the entire building line
i.e. how long is the block if we put them in a single line; we would
achieve this easily by taking one grid-line after the other.
Grid 1 = The linear length of blocks on grid-1 is 4500mm (its that simple), now lets take for others.
Grid 2 = 4500mm also (now you'll notice i omitted the windows and door opening on grid-2, we would come back to deduct those.
Grid A = 3000mm
Grid B = 3000mm
Grid C = 3000mm
Now,
lets add to get the total linear length of building = (4500x2) +
(3000x3) = 18,000mm [its important to group similar dimension especially
when dealing with larger drawings to safe time].
Now that we
have the linear length remember the block works are divided into 2. The
Foundation Blocks (Sub-Structure) and The Building Blocks
(Super-Structure)
NOTE: The length of a standard block (in Nigeria) is 450mm and the height is 225mm for both 6" and 9" blocks....
A. BLOCKS NEEDED FOR FOUNDATIONQuestion: How many courses of blocks are you planning for your foundation? I would use 4 courses for this calculation.
Number
of Blocks needed per course of block = [TOTAL LINEAR LENGTH / LENGTH OF
BLOCK] = [18,000 / 450] = 40 blocks per course but remember I'm using 4
courses hence; TOTAL BLOCKS NEEDED TO COMPLETE THE FOUNDATION = 40
blocks x 4 courses =
160 blocks (whether 6" or 9"
Note:
We didnt need to deduct for openings, obviously in the foundation - we
have none. (If your design has a foundation drawing, then use the
foundation drawings to calculate the nos of blocks needed for in the
foundation and the ground floor plan for the super-structure quantities)
B. BLOCKS NEEDED TO ROOF LEVELQuestion:
What is the height of the structure I'm building? In this design I have
used a building height of 2700mm; this means that the number of courses
I'll have would be = [HEIGHT OF STRUCTURE / HEIGHT OF 1 BLOCK] = [2700 /
225] = 12 courses of blocks.
Number of Blocks needed per course
of block = [TOTAL LINEAR LENGTH / LENGTH OF BLOCK] = [18,000 / 450] = 40
blocks per course but here we have 12 courses of blocks to go. (If you
plan to tie your lintel all round the structure because its a small one,
then minus 1 course taken by the lintel and use 11 courses BUT I don't
advice that, so I'll use 12 courses and use my lintels only over
opening), so;
TOTAL BLOCKS NEEDED TO COMPLETE THE WALLS = 40 blocks x 12 courses =
480 blocks (whether 6" or 9"
BUT,
there are opening where blocks wont be needed so we MUST deduct those out.B(ii). DEDUCT OPENINGS IN B ABOVEOpening in drawing:
a. 750mm x 2100mm
b. 900mm x 2100mm
c. 600mm x 600mm
d. 1200mm x 1200mm
There are no half blocks, so every numbers would be rounded to the nearest whole number.
a. 750x2100
{where 2100 is the height of door; see elevation}Nos of blocks needed per course = 750 / 450 = 1.6667 = 2 blocks
Nos of courses in door = 2100 / 225 = 9.3333 = 10 courses
Number of blocks in 750x2100mm door = 2 x 10 = 20 blocks.
b. 900x2100.
Nos of block needed by course = 900 / 450 = 2 blocks
Nos of courses = 2100 / 225 = 9.3333 = 10 courses
Number of blocks in 900x2100 door = 2 x 10 = 20 blocks
c. 600x600
{where 600mm is the height of window}Nos of blocks needed per course = 600 / 450 = 1.333 = 2 blocks
Nos of courses in door = 600 / 225 = 2.6667 = 3 courses
Number of blocks in 600x600mm window = 2 x 3 = 6 blocks.
d. 1200x1200
{where 1200mm is the height of window}Nos of blocks needed per course = 1200 / 450 = 2.6667 = 3 blocks
Nos of courses in door = 1200 / 225 = 5.333 = 6 courses
Number of blocks in 1200x1200mm window = 3 x 6 = 18 blocks.
TOTAL BLOCKS CALCULATED INTO OPENINGS (in this design) = 20+20+6+18 =
64 blocksNow lets deduct B(ii) from B = 480 blocks - 64 blocks = 416 BLOCKS NEEDED
TOTAL BLOCKS NEEDED TO BUILD THE STRUCTURE (Foundation + Main building) = 160 + 416 = 576 Blocks.But we should consider waste and broken blocks right? - lets add
10% for waste and broken blocks = 576 + 58 =
634 blocks.IMPORTANCE OF THIS CALCULATION:You could use this calculation to:
i) Calculate how much you would spend on blocks by multiplying quantities above by the price of 1 block.
ii) You could also use it to estimate approximately, how many bags of cement would complete the block-works
iii) You could use it to negotiate and have an idea of how much to pay the bricklayer
iv) Plan your budget
Thanks for following; please feel free to ask your questions or share your reservations.... or request any info.