Plenty of good plots around Nairobi slope, and plenty of buyers hesitate over them. The hesitation is usually about cost, and it is not wrong: a sloping site does cost more below ground. What it buys you above ground is often worth more than the difference.

The instinct is to flatten. Cut a level platform, build the house you would have built on flat ground, and retain the difference with a wall at the back. It works, and it wastes the site. You have paid for the excavation and the retaining and got nothing back except a flat plot you could have bought elsewhere for less.

The alternative is to let the house step. Put the garage and the plant at the low end where the ground is already cut, take the living floor in at the natural level so it opens straight onto the garden, and let the bedrooms sit above. The slope does the work that a staircase would otherwise do, and every floor gets a different relationship to the ground.

What this asks for is that the substructure is designed rather than assumed. Foundations stepping down a gradient, retaining where the cut is genuinely retained, and drainage that takes water round the building rather than into it. On a slope, water is the thing that will find you. Every season it runs the same way, and if the building is in that path, no amount of finish will fix it.

The sequencing matters too. Substructure on a sloping site is slow, unglamorous and expensive, and it all happens before there is anything to look at. Clients who are watching progress photographs find those weeks discouraging. It is worth saying at the start that the site will look like a quarry for a while, and that this is the part that decides whether the house is still sound in twenty years.