Case Study residential house in Ngong

Use of beam and block in Ngong for a residential house in Ngong, a black cotton-dominated area, 90% of the area is covered in black cotton. This means extra costs in excavating and backfilling to achieve stable ground during construction. As much as this process is a tussle for many, one cannot escape if the slab in question is the traditional one that entirely lies on the ground.

The beam and block slab is fully suspended and rests on the ground beam, trench excavation for foundation walls only and suspend your slab above the ground. This allows massive savings on excavating and backfilling, as well as formworks bearing in mind the fluctuating steel prices and other construction materials.

About the project

The project is about a residential house in the interior parts of Ngong town, Kajiado county. On half an acre piece of land, the residential building sits on approximately 300 m2 on the ground floor and upper floors. It has four bedrooms all ensuite, a fitted kitchen, a TV entertainment room, and an extended foyer that leads to the rest of the house.

Construction began in early February 2023 and is set to be completed by the end of September 2023.

Clients dilemma

Ngong being an area with predominantly expansive soil, the contractor aimed to use a solution that would circumvent the tedious and expensive process of excavation and backfilling to achieve stable ground for the residential house.

Site visit

Solution by Ecoconcrete

Based on the client’s dilemma we provided a solution that was cost-effective on black cotton soil, saving up to 40% of the overall ground floor slab cost.

No mass excavation was done, thus no backfill was needed, only the trench foundation was do done and the beam and block slab suspended above the ground resting on the ground beam. Fast easy and cost-effective solving the client’s dilemma.  


Building on black cotton soil is made easier with the beam and block-suspended precast slab.

  • No mass excavation and backfilling
  • Quality product as it is factory produced. 
  • It conforms to international standards.
  • Fire/sound resistant.
  • Fast and easy to install.
  • Use of minimal unskilled labor.

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