Case Study: How to Calculate Number of Blocks Required to Fence a Plot of land


Just recently, a one of the numerous questions I got was “Richard please how can I know the number of 5 inch blocks required to fence my land? It is not 4 sided like other plots! This really means we will be doing another post on the topic How to Calculate Number of Blocks to Fence a Plot of land and here is my honest estimate
Well, I’m happy that it was possible to estimate the accurate number of blocks needed to accomplish the fencing of such a plot and today, I’ll share exactly how I did it.
Add Up the sides
You know when we estimate for blocks required for 2 bedroom or 3 bedroom flats, we made mention of external and internal girths.
Well, this time we have just external girths which is the same as the Distance covered by each of the sides of the plot…
This means we’ll need to add up all the 5 sides of the land and then know the number of blocks required on each course.
fence project for irregular plot of land
From the image above, we can calculate the total girth by adding up the dimension of all the sides that makes up the land.;
Side A – B = 25.16m
Side B – C = 12.48m
Side C – D = 37.57m
Side D – E = 17.46m
Side E – A = 19.99m
Total Girth = 112.77m
Divide the total Girth by length of 1 block
Total Girth = 112.77m
Length of 1 block = 0.45m
Total Block on each course = 112.77/0.45
Total Block = 251 Blocks
Now that we have divided the total Girth by the length of 1 block (0.45m), whatever value we got is the number of blocks required to cover the entire plot for 1 course.
Now depending on how many blocks high you want the fence to be, you’ll just need to multiply the value in (a) above by the number.
Let the fence be 8 Blocks high
Assuming you’ve decided to build a fence that us 8 Blocks high, all you have to to in order to get the total number of blocks required is multiply value (a) by 8
Total blocks required for this plot of land would be
Number of blocks on each course X height in Blocks
= 251 X 8 Blocks = 2008 Blocks
Let’s assume this is a farm, our wall is made with 5 inch blocks, we need some block pillars.
It therefore means we need to estimate the amount of blocks to be added for pillars
But you remember whenever we built a fence, there is need for pillars as these makes the wall firm, able to resist wind load as well as vibration due to settlement.
We we night want to work out the space required for this pillar and thus we shall be doing below!
In order for our fence to be strong, we must consider it’s closeness to the road.
From the survey plan, we understand that length E -A measuring 19.99 meters is facing a road which means we need to ensure the fence can withstand vibration resulting from vehicular traffic.
Thus, we provide Block fence at 2.7 meter intervals to ensure our fence walls are firm and would stand for a good number of years.

How many Pillars would be On this plot of land?

From our recent post on how many Blocks to fence a plot of land, we learnt how to map out the number of blocks required for block pillars. Please refer to that post to understand how we arrived at our number of Pillars required for this plot of land.
Pillars Arrangements
Side AB = 25.16m/2.7 = 9 pillars
Side BC = 12.45m/2.7 = 5 pillars
Side CD = 37.57m/2.7 = 14 pillars
Side DE = 17.60m/2.7 = 6.5 pillars (7 pillars approx.)
Side EA = 19.99m/2.7 = 7.4 pillars (8 pillars approx.)
In total, we have 43 pillars.
Total blocks required for Pillars Would be 43 X 3Blocks X Height of fence (in blocks)
What this means is that we have to provide 43 X 3 X 8 blocks and this gives a total of 1032 blocks
Therefore, for this irregular shaped plot of land, we would need a total of 2008 + 1032
Total Block = 3040 blocks + 10% Losses

Understanding the importance of Columns (Pillars) in a fence Project.

Fences are usually Walls built with sandcrete blocks. This means aside the foundation concrete, a sandcrete wall might as well be the weakest of walls. Well, we give thanks to the old engineers who saw the need for pillars which are strategically situated in order to serve as support to the walls, provide extra stability needed for the fence to withstand external forces.
It is important to erect a fence and ensure it has all the necessary support it needs to carry out it’s function as a barrier to unwanted access. This is Why we must consider pillars.

Marking out pillars in a Fence project

In order to mark-out pillars one needs to understand that a lot of factors determine where a pillar is erected And the type of pillar to be erected in a fence Project.
These factors includes;
Location of the fence
Fences located near a road way would always be more stable when there is a concrete pillar place at 2.5 meter intervals. These pillars would help the walls withstand vibration emanating from vehicular traffic. The most preferred could be sandcrete or normal reinforced concrete pillars
Environmental factors 
While sandcrete block pillars could be suitable in dry environment, they may not really be that effective in Swampy environment.
This is because it is a sandcrete block, its strength grows weak as it stays soaked in water most of the time and this really reduces the strength of the walls of the fence.
If your fence or plot of land is located around a Swampy terrain, you might consider a Reinforced Concrete Pillar as this offers more strength and stability to your fence.
Purpose of the Fence
For residential buildings located on dry environment or well drained soil, there might not necessarily be need for concrete pillars. But when the fence is to be built around large facilities or infrastructures, government establishments, hospitals, universities, Military Buildings, etc. A reinforced concrete pillar must be highly recommended and adopted and proper supervision must be in place to ensure proper execution of the project.
Well, it is actually possible to reach Richard to do and awesome job for your fence project. Quickly reach him by filling this contact form and ensure you drop your phone number as a message.

Conclusion: How to Calculate Number of Blocks to Fence a Plot of land

This is probably one of the most reliable estimate you are going to find on the internet about How to Calculate Number of Blocks to Fence a Plot of land especially as most of the experienced bloggers are busy and would never want to disturb themselves with these kinds of estimation. Feel free to consult with the admin whenever you have a question about this post!

Recommended:  What is the Cost of Fencing a Plot of Land (100 x 50 with pillars) - Complete Guide

Written by admin

Hi, I'm Richard Nwachukwu! It is my job to handle the content aspect of this great organization and I'm determined to ensure you get it all right as long as you're handling a construction project in Nigeria!

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