How to Calculate the Number of Blocks for Fence

You have a fencing work to do for your site, and you are wondering how many blocks you need to handle the fencing? Here is a simple way to calculate it.

Take for instance the imaginary site plan measurements we have in the image above.

The site has four sides measuring 20m, 20m, 35m and 15m.

First, get the perimeter of the site which is the addition of all the existing site measurements.

20 + 20 + 35 + 15 = 90metres.

Don’t want to do the calculation yourself, use our simple excel calculator below.

Supposing the height of the fence you want is 3 metres high, to get the surface area of the entire block wall on the site, we will multiply the perimeter by the height of our wall,

which is 90m x 3m = 270m2.

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That gives us surface area but not the number of blocks we need; to get the actual number of blocks, we work with standard rule.

The standard rule for this type of calculation states that 1m2 of wall contains 10 blocks (including the mortar joints between blocks).

The surface area we have is 270m2. So, the number of blocks for our area is 270m2 x 10 blocks = 2,700 blocks.

Now we must consider that in the lifting and transporting of blocks, breakages can occur, also there could be possible errors in site measurements. For this reason, we include what we call safety factor.

A reasonable safety factor is between 5-10%, you can go as high as you wish.

Using 10% as our safety factor, we have to find out what 10% of 2,700 blocks and add it back to the 2,700.

10÷100 x 2700 = 270

270 + 2,700 = 2970 blocks.

That is the total number of blocks you need to make financial provision for on site, to be able to fence a site of such measurement.

Note that calculation applies for 9 inches, 6 inches and 4 inches blocks because the calculation is taken from the length and height of a block as opposed to the thickness (9, 6 or 4 inches).

Read Also: How to Effectively Read a Floor Plan like a Pro

 

Using our Excel Template

Enter the perimeter and height of your fence wall in the green-coloured boxes.

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