The maximum size of house for a plot of land

By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

22 October 2017

I made a fundamental error in last week’s article: I multiplied the numbers instead of dividing them! I still can’t believe that I made such a mistake, all I can say is I am sorry. I was trying to find out how far one would need to be in order to see the planet earth in its entirety.

I did an experiment and established that I need to be one unit of length away to see an object that is 3 units tall. Thus, since the earth is 12,800km “tall”, I would need to be 12,800km divided by three = 4,267km away for the entire planet to fit in my field of view.

This idea of the field of view can also be applied in the design of buildings. A few years ago, I asked an architect how to determine the right size of a house for a given piece of land. My concern was that many houses appear to be too large for their plots.

The architect told me that a person should be able to see the entire building while standing inside the plot of land. He pointed out that this is one of the reasons why the Kenyatta International Convention Centre (KICC) in Nairobi appear so “majestically beautiful” – his words, not mine!

You can view the whole 28-storey tower while standing inside its compound without moving your head to “scan” the height. For that reason, the KICC appears more “imposing” than the taller, 36-storey Times Tower.

With this in mind, what would be the appropriate size of a house built on the common “50x100” plot? The gate is usually along the shorter (50-foot) side. So the question is: once you enter the compound, how far should the house be in order for you to see its entire width?

Last week I found the when standing one unit of length from a wall, my field of view if five units wide (horizontally). Now the “50x100” is usually surveyed in metres: it is 15m x 30m. So, to see the entire width of the plot, I would need to be 15 divided by 5 = 3m away. Thus, the house should be located at least 3m from the gate.

That takes care of the width; what about the height? The vertical field of view is three times the distance away. When standing facing forward, my eyes are 1.6m above the ground. One half of the field of view is above eye-level and the other is below.

The upper field of view is 1.5m high for every 1m away. Thus when I am 3m from the house, the maximum height I can see without tilting my head upward is 3 x 1.5 = 4.5m above eye-level. Thus the tallest house visible should be 1.6m + 4.5m = 6.1m from the ground to the highest point on the roof. Anything taller than that would appear too big for the plot.