How to calculate a number of blocks from foundation to DPC for your building project.

Looking at your house plan designs or drawings, the question or challenge facing most clients is “How many blocks do I need to complete this project”?

If you find yourself facing these challenges, don’t worry I am here to explain simple steps you can take to calculate a number of blocks required to kick start your house plan building project from foundation to DPC( damp proof course) level.

In my next article, I will be explaining how to calculate the number of blocks from DPC( damp proof course) to roof level. So please try as much as possible to subscribe to my newsletter to get new updates about tips required to execute your building projects.

THE GROUND FLOOR PLAN

The first thing you need to lay hold on in your house plan drawing is the ground floor plan. The ground floor plan contains vital information that will help you in calculating the number of blocks needed to complete your  DPC(damp proof course) level work.

If you find it difficult to interpret your ground floor plan please refer to my article on “How to read and interpret the ground floor plan of any Nigeria house plan designs”.

I will be using a one-bedroom apartment to explain the necessary steps needed to calculate the number of blocks required up to the damp proof course level. If you take time to look at the ground floor plan image below, you will notice that there is provision for total dimensions for the length and width of the house plan building project.

From the image, the total dimension for the length of my building is 11.1(meters) while the dimension for the width of my building from the image is 10.4(meters).

Having these in mind the next thing you need to do is………..   ……….    ……….

GROUP ALL SEMILLAR WALL LINES  ALONG THE LENGTH DIRECTION

To do these take a proper look at my one bedroom image below, see how I group my wall lines to make up the full lengths and widths in other to be able to get the total lengths of all the wall line in the one bedroom apartment.

From the image the length of the one bedroom apartment has four major wall lines numbered 1 to 4 and a minor wall line of about 2.6(meters).

Since you know the length of 1 major wall line to be 11.1(meters). the next thing is to multiply the wall lines by the length of one wall line. This becomes;

NUMBER OF MAJOR WALL LINES ALONG THE LENGTH DIRECTION = 4

LENGTH OF ONE MAJOR WALL LINE = 11.1M

TOTAL LENGTH OF ALL MAJOR WALL LINE = 11.1 X 4 = 44.4(meters)

Recall that we have a minor wall line length of about 2.6m
Adding the major and the minor wall line lengths together give us.

MAJOR WALL LINE LENGTHS = 44.4m
MINOR WALL LINE LENGTH  = 2.6m

therefore Total wall line lengths in the one bedroom apartment will be

MAJOR WALL LINE LENGTHS + MINOR WALL LINE LENGTH

that is,      44.4M + 2.6M = 47(meters)

Now, you know all the measurement for the lengths of all wall line along the length direction. Similarly applying the same method you can calculate for all wall lines along the width direction. Looking at the ground floor plan again but this time considering the wall lines along the width directions. The red arrows indicates the directions of the various wall lines, while the wall lines is being represented by the double thick black lines in the above ground floor plan. look at the above image carefully, you will observe that the wall lines in the width directions needs to be grouped.

GROUP ALL WALL LINES ALONG THE WIDTH DIRECTION

In other to do these correctly, check for the full length of the wall line along the width direction, from the image above the length is 10.4(meters). Now locate the first wall line, you will notice that the width is about half the full width but when you combine it the second wall line in the width direction it now make up a complete full width. So to get one full width I combine the first and second wall line together. You will do same thing for the rest wall line when grouping yours. see the image diagram below.

From the house plan ground floor image, you will notice I group all wall lines in the width direction to be four after combinations.

Now the length of one major full width is 10.4(meters), the next thing you need to do now is to multiply the full width length by the numbers of all major wall line along the width direction. This becomes;

NUMBER OF MAJOR WALL LINES ALONG THE WIDTH DIRECTION = 4

LENGTH OF ONE MAJOR WALL LINE = 10.4M

TOTAL WIDTH OF ALL MAJOR WALL LINE = 10.4 X 4 = 41.6 (meters)

NOTE , the number 4 wall line is not a complete full width but I consider it has
full width to compensate for any wall line width that is not consider during the grouping exercise. Now since we do not have any minor wall line along the width direction, it simply means the total width of all major wall line will be used as our total width length.

that is;

MAJOR WALL LINE WIDTH LENGTHS = 41.6 ( meters )

We are almost there, if you did not understand this first part of the calculation process, please feel free to comment below, I am willing to help you out again and again but If the first part is clear enough please follow me through the next calculation steps on how you can determine the number of blocks you need to kick start your house plan project from foundation to DPC level.

From our first result;

TOTAL MEASUREMENT OF WALL LINES IN THE LENGTH DIRECTION  =   47 ( meters )

TOTAL MEASUREMENT OF WALL LINES IN THE WIDTH DIRECTION  = 41.6 ( meters )

ADDING BOTH MEASUREMENT WE HAVE;

47m + 41.6m =   88.6 (meters )     (  This value represent the measurement for all wall lines both length and width direction in the ground floor plan image above  )

 DIMENSION OF A 9″ HOLE BLOCK WALL

Now lets consider the dimension of a 9″ hole block, from the image below you will see notice that the length, width and height of a 9″ hole block are 450mm, 225mm and 225mm. Since the laying of the block is usually by the “length side” we are going to use the dimension of the length to determine how many number of 9″ blocks will be enough to lay through the total length of 88.6(meters).

To do these,

Total measurement for all wall lines from my previous calculations = 88.6 (meters)

Length of  9″ hole block = 450mm = 0.45(meters)

Therefore;

No. of blocks needed for the first course will be;

Total measurement wall lines  / length of one block

= 88.6/0.45 = 196.88 = 197 blocks approx.

Since we have being able to establish the numbers of blocks that is needed to lay on the first course to be 197 blocks. The next thing you need to do is to determine the height of the DPC. Normally the height of the DPC can be found on the sectional part of the architectural drawing or can be given by the site engineer depending on the nature of the land.

From the house plan sectional drawing the height of the one bedroom DPC building is taken to be 1.05 (meters). Please study the image above to see the height of the DPC building project, If the height is not given in your own house plan section, you can deduce the height of DPC by simply adding the depth of foundation to the height of the number of blocks above foundation level and the thickness of DPC Slab concrete.

NO OF BLOCKS CONTAINED IN A DPC HEIGHT OF 1.05m

For a DPC height of 1.1m the number of blocks that will give you the height of 1.1m can be deduce by dividing the DPC height by the height of one block. 

That is;

DPC HEIGHT = 1.1m

HEIGHT OF BLOCK = 225mm = 0.23m

NO. OF BLOCKS  WILL BE = 1.1m / 0.23m = 4.78 = 5 Blocks approx.

Yes we are almost there, since I now know the total numbers of blocks that will be used for the first course to be 197 blocks and the total number of blocks needed for a DPC height of 1.1m is 5 blocks. To get the total number of blocks from foundation to DPC  becomes very simple.

That is;

No of blocks needed for first course = 197 blocks

No of blocks needed to get a DPC height of 1.1m = 5 blocks

Therefore;

TOTAL NO. OF BLOCKS NEEDED TO WORK UP TO DPC LEVEL WILL BE = 197 blocks x 5 blocks = 985 blocks.

This is just a simply way of calculating the number of blocks you need to achieve your DPC project work. if you are using a different house plan all you need is to study this process very well and apply it to your own ground floor plan and if there is any aspect of the calculation you will want me to explain more please don’t waste time to let me know. I am always available to help.

Thanks for spending your time with me, it my pleasure and I appreciate the quality time you spent going through this article and don’t forget to subscribe to my news letter to be the first  to get updates regarding house plan matters. Good luck.